Multisplit fault

[back2space]

Guys,


Another fault now it seems... having had the return air sensors replaced sensors to remote sensors on the LG multisplit of mine there is now a new problem come to light.

The bedroom unit seems to have developed a problem in that when the living room is switched on and is at thermostat on & when the bedroom unit is thermostat off the unit should sample the air by running the fan every minute for 10-20 seconds or so until the heat is cleared from the coil and the coil sensor detects the coil is cooler again it goes off again sampling the air again later.

Obviously only if the coil is upto temp otherwise it doesnt do this... All good so far. However after the first 10minutes of the units being turned on its doing the air sampling correctly, fan on for 20seconds then fan off for another minute but after a while the bedroom unit seems to stick on air sampling mode and the fan continues to run blowing warm air continuiously (despite thermostat off) due to EEV valves being opening slightly continual blowing of warm air is heating the room up .

If I put the set point to 16C from 22C this doesnt make any difference. Its as if the coil being warm is causing the fan to run continuously and the coil is staying above the cold air prevention point. Set point of 18C room temp is reaching 25C with the constant fan running air sampling.


Its not the remote sensor i installed as if I have the bedroom unit only switched on cuts in and out fine. Also if I change the fan speed from high to low the fan stays on low which if the unit was calling for heat the fan would switch to high so I know its not the sensors. We have also swapped sensors round to the living room and problem stays with the unit.

I am wondering why the fan is continually running on the bedroom unit even after thermostat off. This is more than the air sampling its just continually running. If I turn the lounge unit off though the bedroom unit then goes off and as the coil goes cold the fan shuts off then. Its as if due to the coil being warm the fan is running all time despite unit being in thermostat off.

Normally in air sampling the fan starts and you can feel a blast of warm air but after 10seconds or so you feel the air start to get cooler then cold air prevention kicks in due to low circulation of refrigerant and then the fan cycles off again till the next air sample is due a minute later this is causing lots of residual heat to be released into the room with the room temp continually rising unless I turn the unit off.

The air blowing during the air sampling does not get cooler so its as if there is higher than normal refrigerant circulating inside the unit? Could the EEV be opening too far allowing more refrigerant to circulate and a higher coil temp?

The bedroom unit if switched on its own works fine and cuts out on thermostat off.

The unit is not on High Ceiling mode nor does the compressor seem to speed up when this is happening.

I can never get any response from the installer and no other engineers will work on another installers install as its under warranty so I dont know what to do.

Any ideas?

[back2space]

Has been fine all day then when I go back in the bedroom tonight room temp is 23C and fan is just constantly blowing luke warm air. Set point is 20C.

Living room unit is at 20C and seems to be struggling to heat.

Notice hendrag hasnt been in touch again and also I have emailed LG and no response from them!

WIsh I had never got this equipment a bloody fan heater would have been better control

[back2space]

*********************

[airefresco]

You´ve probably already tried this, but have you switched the power off to the unit (everything) for a minute or so, then restarted. Worth a shot.

Another thing to try. again unlikely to be this, but swap the sensor from the two rooms around, to prove it´s not a faulty sensor.

[al]

Backspace

Bit off the wall, but have you accidently activated the emergency heat/cool option?? i used to do this when first installing high walls, previous suggestion of power off should clear this but of course it's an lg!!

Al

[back2space]

You´ve probably already tried this, but have you switched the power off to the unit (everything) for a minute or so, then restarted. Worth a shot.

Another thing to try. again unlikely to be this, but swap the sensor from the two rooms around, to prove it´s not a faulty sensor.

Yes power has been switched off this morning for half an hour the powered up, ran fine all day but tonight is playing up.

Did the same last night.

Will be working ok again tmrw during the day and then come night time will mess up again.

There are no fancy controls its just an infra red controller.

ITs deffo not the sensor as this has been swapped over with the lounge unit and the fault stays with the unit.

The thing is the unit is thermostat off because when the unit is thermostat off the fan speed will go down to low from high and will sample the air occasionally from whatever its set at.

I have put the fan speed back to high and the fan speed is staying on low.

Living room unit doesnt have this fault.

[back2space]

Backspace

Bit off the wall, but have you accidently activated the emergency heat/cool option?? i used to do this when first installing high walls, previous suggestion of power off should clear this but of course it's an lg!!

Al

HI Al

Unit is not on emergency operation. I have been asleep all day (im a night worker) so system has just been left turned on and then I woke up and room was really warm.

You see the air sensing operation only works if the coil is warm and because less refrigerant is circulating on units that are thermostat off, fan cycles on for about 20 seconds and when the little bit of heat in the coil is blown out and the coil cools the fan cycles back off to avoid cold air prevention unit is then in standby until it samples the air again. THis works during the day but the last two nights fan is staying on its as if the coil is staying warm or too much refrigerant is flowing through the coil meaning it isnt cooling down enough for cold air prevention mechanism to kick in.

If i switch off the lounge unit that is always on a higher set point the outdoor unit switches off and the bedroom unit then goes onto standby as the coil has no refirgerant circulating then due to outdoor unit being off. OBviously if this unit was calling for heat and it was a problem with the return sensor it would not go onto standby when i switched the lounge unit off.

Have also noticed that if only one unit out of the 2 is switched on the wattage drawn is higher than if I have both units switched on & one of the units is in standby the wattage drawn goes down.

Have still had no response from LG to my email.

[Mac1]

HI Al

You see the air sensing operation only works if the coil is warm and because less refrigerant is circulating on units that are thermostat off, fan cycles on for about 20 seconds and when the little bit of heat in the coil is blown out and the coil cools the fan cycles back off to avoid cold air prevention unit is then in standby until it samples the air again. THis works during the day but the last two nights fan is staying on its as if the coil is staying warm or too much refrigerant is flowing through the coil meaning it isnt cooling down enough for cold air prevention mechanism to kick in.

If i switch off the lounge unit that is always on a higher set point the outdoor unit switches off and the bedroom unit then goes onto standby as the coil has no refirgerant circulating then due to outdoor unit being off. OBviously if this unit was calling for heat and it was a problem with the return sensor it would not go onto standby when i switched the lounge unit off.

Have still had no response from LG to my email.

Your email was received yesterday, we spoke on the matter this morning.

As discussed, in heating mode the LEV's in any off cycle units remain slightly open to assist Oil return, this is true with all manufacturers Multi-Split Systems.
I believe the Lounge unit is under-sized and the Bedroom unit may be oversized for the room loads. Given the very cold weather this past week, the Lounge unit is not achieving set-point and the hot gas passing through the Bedroom unit is sufficient enough to raise the coil temperature and keep the fan running. The fan will not switch off until the coil heat is dissipated.

I hope our discussion has given you a better understanding on the way the system operates. I don't understand why your last blog states you've had no response from LG, when quite clearly we spoke first thing this morning.

[back2space]

The last blog was written at 12:25am half an hour after midnight.

Having just spoke to you on the phone... The lounge unit is very much so struggling. The lounge unit is 3.5kw and is in a smaller room than the bedroom, bedroom is 22C at present with set point of 18C... you have explained the reason for this which is risidual heat so thats ok.

I am at a loss as to why you say its undersized, as per the combination tables with an indoor ambient of 20C and outdoor of 0.5 I should have 3.52kw of heat coming from the unit. At 7C outdoor temp it has 3.90kw rated capacity, surely a drop of 452watts is not enough for the unit not to be able to heat above 20C

Previously before getting the a/c installed a 2kw fan heater was used in this room to heat it up and with an outdoor temp of -3 this was still sufficient.

This managed fine and temps could be raised to about 24C any higher and it was too hot.

I do not think a response of "take it all out and install electric storage heaters" is what LG should be promoting. Especially when you cant explain why the unit is failing to heat a room up but a 2kw fan heater is managing it no problem.

Its strange as having just turned the bedroom unit off at the remote control which has been in standby (thermostat off state) all day and the fan coming on occasionaly to get rid of heat from the coil as you explained. The air off temp from the lounge unit has increased by about 5C and wattage drawn has also gone up from 1067watts to 1402watts when only 1 unit is operating. Air off temp with only 1 unit switched on is 43C. However if both units are switched on but only 1 unit is calling for heat the air off temp drops to 36, its this drop in air off temp where the performance seems to be getting lost. WHy would the outdoor unit slow down if 2 units are switched on and only one is in standby but speed up if only one unit is physically switched on?

WHat could the reason be for this?

Please explain...

[back2space]

No dedication to customer service whatsoever!

[p_p]

Send Hendrag a pm, see if you get a response then.

PP:mad:

[back2space]

Have done. The reply above was from Ken who works in the helpdesk.

Not heard anything else after my last request, only that I should pull the system out and put in electric storage heaters!!!

[p_p]

You should have gone for mitsi electric from day one, we install lots of it, install it correctly and it will give years of trouble free service.
Its a shame HENDRAG never got back to you himself, he's actually a top guy in the industry and very well respected.


Good Luck


PP

[back2space]

Yes I know begginning to regret it!

To get one of LGs engineers out costs £300!!!

I think under circumstances they should send one to me anyway since installer gone AWOL.

[p_p]

That would be a good gesture on LG's behalf, who knows maybe hendrag might pick up these posts and take the bull by the horns so to speak.


PP

[p_p]

If these units are in warranty, surely there is some comeback on the distributor, most have there own tech support now aswell as the manufacturers, thats of course if you know who the distributor was.
Just a thought!

PP

[back2space]

If these units are in warranty, surely there is some comeback on the distributor, most have there own tech support now aswell as the manufacturers, thats of course if you know who the distributor was.
Just a thought!

PP

yes I know who the distributor was, they quoted me £40 for each remote sensor when I got them for £18 through lgcomfort cooling.

Got someone coming tmrw to clean the coils hes going to check everything for me and speak on my behalf to LG as im going to put everything to him.

[back2space]

That would be a good gesture on LG's behalf, who knows maybe hendrag might pick up these posts and take the bull by the horns so to speak.


PP

Doubt it very much! It was a fleeting visit from him last week to the forum I think... hes ran for the hills!

What gets me is how he bangs on in a/c magazines about "getting it right for the customer" and how extra time with the customer sorting issues out and concerns goes a long way in customer service. Well its true it does but LG clearly are wrong about this as they have not come out to discuss problems etc.

[l'robot]

Hendrag is too busy writing blogs titled "Oh stop complaining" to reply!
http://www.heatingandventilating.net/blog/view_entry.asp?id=77

[p_p]

Hi Back2space

How did you get on?



PP

[back2space]

Hi Back2space

How did you get on?



PP

With LG... Non existant

With the units... waiting for a competent engineer to arrive any time, someone old style who is going to actually look into my problem.

I am getting comms errors cominig up a lot as well even if the units are turned off.

So hes going to look into it all for me as well asgive the units a clean on the outdoor coil.

[p_p]

Lat us know how you get on, what/If they find anything wrong.
Are you an engineer yourself.

Good Luck



PP

[back2space]

Will do! Keep you all posted!

[p_p]

Back2space.

Check you pm.


PP

[back2space]

Have replied mate!

[back2space]

Oh and im not an engineer I work in a facilities helpdesk.

[AbsoluteWDJ]

Hi back2space...I haven't read the whole history of your problem and i just quickly browsed this issue but at any point after installation did you receive a commission report from the installer? Or has anyone since worked on the refrigerant...(reclaiming or adding) I apologize if this has been discussed and i'm personally not a fan of LG. Have you been having issues from day one of install? If so, I would probably start with reclaiming and measuring, nitrogen test, deep vacuum or triple and recharging the correct amount into the system. Are you on speaking terms with the installer?

[back2space]

No the installer is avoiding me, I have had to have him back out a few times each time he denies any problem and just wanted to be off.

However I have since had 3 diff engineers from diff companies all who agree its not behaving correctly.

On cooling it seems to be fine but on heating is where we develop the problems.

The latest engineer who has come out to look at it is a member on here p_p and he spent 2 hours looking at the system.

he says the system is not controlling correct... refrigerant charge etc is fine. He is going to ring LG technical tmrw and request they send one of their engineers, could be a PCB fault in outdoor unit.

[AbsoluteWDJ]

No the installer is avoiding me, I have had to have him back out a few times each time he denies any problem and just wanted to be off.

However I have since had 3 diff engineers from diff companies all who agree its not behaving correctly.

On cooling it seems to be fine but on heating is where we develop the problems.

The latest engineer who has come out to look at it is a member on here p_p and he spent 2 hours looking at the system.

he says the system is not controlling correct... refrigerant charge etc is fine. He is going to ring LG technical tmrw and request they send one of their engineers, could be a PCB fault in outdoor unit.

First i would question why the installer is avoiding you...If you have a problem with what they've supplied and installed...It shouldn't just be your problem it's theirs as well....They hold any warrenty. Did you receive any commission report? The situation your in is a middle man predicament....The installer will point to LG and LG will point to the installer! If you can get an LG engineer out to you with out charge then go for it....If you can get the LG and installation engineer together then even better...Remember...You've paid!! It's either bad design/install or a problem with the equipment but you've got to make sure it's not design/install otherwise the LG engineer will walk all over it! Like I say, in my experience LG sometimes defy all logic but if they (the engineer) represent the product, they are hardly going to admite to their employers to be the problem.....Have some evidence my friend!

[back2space]

Ive had someone very reputable out who has checked all that over.

He said it wasnt the best installation but it is functional and no crossed wires/pipes etc.

So the problem is with the outdoor unit for sure.

The installer did it as a favour for me in exchange for me to put their name round my work due to me working in facilities manamagent we look after a/c and refrigeration etc.

SInce then due to the wash out of summer we had he either got no work etc. But he did it as a favour and as result made no money on the install. SO for him being a director of company he wont keep coming out.

I ring and ring and ring and leave messages, promises to call back but never does.

[AbsoluteWDJ]

Ive had someone very reputable out who has checked all that over.

He said it wasnt the best installation but it is functional and no crossed wires/pipes etc.

So the problem is with the outdoor unit for sure.

The installer did it as a favour for me in exchange for me to put their name round my work due to me working in facilities manamagent we look after a/c and refrigeration etc.

SInce then due to the wash out of summer we had he either got no work etc. But he did it as a favour and as result made no money on the install. SO for him being a director of company he wont keep coming out.

I ring and ring and ring and leave messages, promises to call back but never does.

Who brought the system?

[back2space]

He did from distributor Dean & Wood.

[AbsoluteWDJ]

If you are sure its a problem with the outdoor unit....control side, then by all means get LG to investigate. I would have the installer there though because they are the people who hold the warrenty that you are entitled too

[back2space]

When i rang installer i left message and rather than him call his secretary rang and she said that the parts warranty can be dealt with by any contractor and not just him however i would have to pay contractor for their labour.

[Electrocoolman]

Perhaps you've 'cried wolf' too often?

[back2space]

Perhaps you've 'cried wolf' too often?

No I woudnt say that at all. I have repeatedly rang him about the same fault since i got the system he thinks im imaginging it or something as he came out and spent about 5minutes checkin system and said it was ok. But the guy who came out off the forum spent 2 hours testing it and agreed from start that the system is not working correctly as have the other engineers who attended.

The very first time i called him out was over one of the return air sensors, it was out of calibration by about 2C. So if i set 21C it reached 19C First response from LG when i contacted them was it is not close control you will have to adjust the temp. SO if you want 21, YOu have to set to 23! What a load of tosh, i complained and the installer then rang LG and was told the sensor needed replacing, so the sensor was replaced and cooling mode works fine on said unit.

Its simply not good enough im really getting stressed by it all it seems to be is excuses after excuses they need to listen as the LG reputation is going to be dirt otherwise,, especially on a forum.

Now with all the problems above i cannot believe i was told by ken at lG technical "YOU SHOULD RIP THE UNITS OUT AND PUT STORAGE HEATERS IN"

Perhaps that should be said to every customer wonder how long that will last for.

This apauling service that I have receieved from LG has been passed onto friends and other engineers who all agree that there is a fault and that its discusting how this is being dealt with.

I would never reccomend LG to anyone in fact the forum is riddled with complaints about LG equipment and service etc. So I dont think its a one off is it.

They will always be Lucky Goldstar with service as it is.

P_P off the forum who visited is speaking to LG tmrw as he received an email from Graham Hendra saying " to contact technical support who will be abe to help"

So lets see how far he gets with it!

[RedEye]

LOL, Ken used to be the tech guy for Dean & Wood!

[back2space]

Its bloody rediculous, there saying it falls back on the installer but ive had 2 independant engineers out who all agree there is a control problem. Ken says that there poss maybe a problem but its upto the engineer to diagnose the problem!

IM A FUMING at the mo, companies just passing the book!

WORST COMPANY I HAVE EVER DEALT WITH!

[back2space]

removed as in talks with installer at present.

[nike123]

It appears that you promised some contract, that you are unable to ensure, to guy who acquired you AC unit below market price and made instalation for no compensation except for expected contract.

You get what you pay for! In this case you got something for nothing.

You did not pay full price, and you did not get full service.
He thinks (with right) that you did not complete your part of agreement and you are left without support, which is, by me, civilised minimum what he could do.

I think you should stop being scanty (you should afford it, since you saved at instalation and purchase price), and pay for new part and labor, to establish with certainty, that you have faulty control (as suggested by two technicians) and, if that is the really the case, ask for reimbursement as proposed by that guy Mark.

If that is not the case, you should live with badly designed product like many, many other customers of al kinds of products around the world, or you could sue LG at court that he sells products that are not conforming to their specifications.

[airefresco]

You´ve not removed the company name, they are in the reply to you, second line and last line of the first paragraph. :) Or is that deliberate?

[back2space]

Airefresco have amended now thanks!

Nike123, whatever I have paid for a system its still under warranty, i never promised a contract and it was a case of I would pass details onto the direct people rather than having to go through the long way round to get in through the doors of our company.

[superswill]

pass me my tin opener,for these worms

[Brian_UK]

Sorry back2space but you still left both company names in your post.

I have edited them out as we do not want public airing of dirty washing.

You have now, unfortunately, come up against the problem of "doing a deal verbally".

Both sides are in disagreement with what was originally said or agreed and I don't believe your paths will cross again.

[back2space]

Sorry back2space but you still left both company names in your post.

I have edited them out as we do not want public airing of dirty washing.

You have now, unfortunately, come up against the problem of "doing a deal verbally".

Both sides are in disagreement with what was originally said or agreed and I don't believe your paths will cross again.

Sorry Brian i should have edited on computer not on PDA as it doesnt looked to have sent request...

[back2space]

pass me my tin opener,for these worms


How very dare you superswill!!! WOuld you rather not have a can opener for a tin of beans or some cat food or something? Much more edible than worms!

:confused:

[nike123]

Nike123, whatever I have paid for a system its still under warranty, i never promised a contract and it was a case of I would pass details onto the direct people rather than having to go through the long way round to get in through the doors of our company.


The supply and installation of this equipment for you was part of a deal, suggested by you and accepted by me, with the aim of getting $&%$^ onto the ****** sub-contractors list, I supplied the plant at less than cost and installed it at a loss to me, all of this was acceptable to us only with the view of getting us on with %^$&£, this has not happened.
That looks to me as deal and promise.
From his point of view, he has hanged!

Regarding your "erratic unit" and waranty, I did not found it 100% as such in these hundred posts, mostly because there is no systematic approach and measurements made and recorded of qualified person and then published here. It appears that that is also the case with your partner in deal who is carrying waranty.
Someone said "this" and someone said "that" is no way of dealing with complex control logic of unit. That is why I cannot accept these opinions made by you or anyone else in that case as something not disputable.

Since bad deal put you in this situation I proposed you that solution in my previous post as one which is most likely to bring end to this saga.
And, if hapened that you are right, you will be covered for parts.
Labor costs is something what you will probably have to live with.

[back2space]

That looks to me as deal and promise.
From his point of view, he has hanged!

Regarding your "erratic unit" and waranty, I did not found it 100% as such in these hundred posts, mostly because there is no systematic approach and measurements made and recorded of qualified person and then published here. It appears that that is also the case with your partner in deal who is carrying waranty.
Someone said "this" and someone said "that" is no way of dealing with complex control logic of unit. That is why I cannot accept these opinions made by you or anyone else in that case as something not disputable.

Since bad deal put you in this situation I proposed you that solution in my previous post as one which is most likely to bring end to this saga.
And, if hapened that you are right, you will be covered for parts.
Labor costs is something what you will probably have to live with.


Ok well perhaps the engineer may post on here when he has read this to back up that the system not working correctly.

He had pressure gauges, manifolds and measured air off temps and his conclusion was it is not working properly.

But I will leave it for now and see what I hear back from the installer to my response.

Thank you.

[frank]

As I'm sure Abe will confirm, legally, your contract is with the installer who took your money. You do not have any contract with the manufacturer and therefore, they are not obliged to honour any warranty problems that you have.

The warranty is issued by the manufacturer to the installer. Any assistance you are getting from the manufacturer is in good faith only.

If I were you, I would tread carefully when 'calling' or 'slagging' or constantly complaining about the manufacturer on here. They just might wash their hands of you and then you will be in 'stuuck'.

While I sympathise with your situation, it doesn't sound like the installing company have done the best by you, and from what you say the arrangement was based on, it must be asked 'did you keep your part of the bargain?'

Getting peoples backs up is not always helpful and more times than not it leads to a broken working relationship.

I look forward to p_p posting his findings on here.

Good luck with the problem by the way as this type of situation is never nice.

[p_p]

Hi All

I popped in to look at this problem last tuesday as I was working literally down the road.
When the lounge is set to 25c and the bedroom 20c both units are heating fine, air off 40c however when the bedroom reaches setpoint, there appears to be too much refrigerant still entering the coil ( LEV staying open to much )thus keeping the fan running so it keeps heating the room and the air off temp is actually higher 36c than the lounge that is still calling for heating air off 32c.
The outdoor unit winds down to 360psi and the lounge unit struggles to make setpoint, turn the bedroom unit off and outdoor ramps up to 450psi and air off back up to 40c even though room is near setpoint at 24c.
It will continue operating in this manner until the lounge reaches setpoint. Hence bedroom temp 25c
It operates like this on both systems which ever unit is set to the higher setpoint this is the temp both systems will attain, there doesn't appear to be any individual control.
If the bedroom is set to fan only and the lounge to heating, again the bedroom temp will start to rise giving an air off higher than the lounge.The only way to stop this is turn the unit off in the bedroom . ( coil still warms up but fan will not run ).
Another independant engineer has looked at this and agreed the system is not operating correctly.
I have spoken to LG on this matter and they agree there 'appears' to be problem with the system, and I am of the understanding they are now going to investigate.
However as I have stated to Back2space if Lg say this is how our system works then you will just have to live with it ?
We installed 3 multisplit Mitsi's 3 weeks ago and whatever the set point is to each room that is the temp that is maintained so why should Lg be any different.
I think there could be a software problem but we will wait and see what LG come up with.

Regards

PP

[back2space]

UPDATE:

Email received from installing contractor last week 21st March saying he was going to speak to LG and ring me back on the 23rd with update.

Still nothing from him but have heard from Graham Hendra via email on Thurs 26th who advised the following:

Today I spoke with the installing contractor

He will be in contact about your machine together some resolution will be found

regards

Graham Hendra
General Manager Airconditioning LGEUK

Still waiting to hear from the installer yet though.

[Mr Memory]

Has been fine all day then when I go back in the bedroom tonight room temp is 23C and fan is just constantly blowing luke warm air. Set point is 20C.

Living room unit is at 20C and seems to be struggling to heat.

Notice hendrag hasnt been in touch again and also I have emailed LG and no response from them!

WIsh I had never got this equipment a bloody fan heater would have been better control
As Frank mentioned, quit slagging off manufacturers and maybe someone will want to help you.

Firstly in your OP you provided not one model number! If you try to contact LG (or one of their distributors), you will be required to provided this as a minimum, or it is unlikely that you will get any help.

LG make very good equipment now (compared to the bad old days), and any AC system can and will need some sort of attention during it's lifetime!

Try e-mailing your question (WITH model numbers) to airconhelpuk@lge.com or call their technical helpline, and they WILL help you out - don't be telling anyone otherwise, because it is simply not true!

[back2space]

As Frank mentioned, quit slagging off manufacturers and maybe someone will want to help you.

Firstly in your OP you provided not one model number! If you try to contact LG (or one of their distributors), you will be required to provided this as a minimum, or it is unlikely that you will get any help.

LG make very good equipment now (compared to the bad old days), and any AC system can and will need some sort of attention during it's lifetime!

Try e-mailing your question (WITH model numbers) to airconhelpuk@lge.com or call their technical helpline, and they WILL help you out - don't be telling anyone otherwise, because it is simply not true!

Revival of old post or what... feb 09!

yes no model numbers were given but anyone who looks at my postings or regular on the forums will probably know the model numbers.

Emailing LG... done this many times, over many different problems... (currently failing to start when the timer is used) but no resolution in place... just passed back to the installer (who now is bankrupt and no longer in business but apparently owes lots of monies!)

I would say a single lg split might be ok, but a multisplit is just asking too much for the lg equipment to work... control strategy is shoddy and all over the place.

Because I have spent a small fortune on engineer visits all agreeing it is not operating properly lg still dont want to know.

I since email them myself now as cannot afford any more call outs!

The point about slagging off manufacturers. Im sure you would be doing the same if your new plasma tv wasnt working and u was getting no where with customer services etc. Its freedom of speech and the view of most engineers is that LG is cheap tat and they would avoid.

My experience probably just backs that up. If LG wants a good reputation then they need to build on that and sort the issues out with their equipment.

[cadillackid]

back2space: if you are still having these issues with your system you might look into seeing if LG will replace the PCB's in that system for you..

that Multi-split had not been out for a real long time when you purchased it.. they have likely since upgraded the software in the indoor and outdoor boards and that may just fix the issue..

since you are in a facilities helpdesk i think you are more than qualified to R&R the PCB's in the outdoor and indoor units...

the other thing that crossed my mind is that the LEV for the bedroom unit could possibly be bad.. causing an invalid position signal sent back to the PCB.. basically the vale would report its open at 10% when the physicval valve might be at say 20%.. allowing more refrigerant flow through the bedroom unit.. and either warming the coil up too much or causing condensation in the liquid line which might cauyse a warmer than normal liquid line reported back to the main PCB telling the system to ramp down on the compressor....

I know this an old post but it sounds like the issue was never resolved...

the other thing I find with many of the chinese made multi-splits is that the outdoor unit does not have the capacity to handle all of the indoor units operating at the same time..

to avoid excessive defrost calls or the possibility of condensed refrigerant in the outdoor coil during cold outside temps these units will ramp down the compressor even when multiple indoor units are calling.. this is done to keep the outdoor coil temperature up a bit..

in my opinion thats not right.. if I buy a 12+12 system I should be able to run both indoor units and expect the outdoor to run flat out but many do not have the outdoor coil area to support both indoor units in heat esp at lower ambient temperatures...

-Christopher

[back2space]

back2space: if you are still having these issues with your system you might look into seeing if LG will replace the PCB's in that system for you..

that Multi-split had not been out for a real long time when you purchased it.. they have likely since upgraded the software in the indoor and outdoor boards and that may just fix the issue..

since you are in a facilities helpdesk i think you are more than qualified to R&R the PCB's in the outdoor and indoor units...

the other thing that crossed my mind is that the LEV for the bedroom unit could possibly be bad.. causing an invalid position signal sent back to the PCB.. basically the vale would report its open at 10% when the physicval valve might be at say 20%.. allowing more refrigerant flow through the bedroom unit.. and either warming the coil up too much or causing condensation in the liquid line which might cauyse a warmer than normal liquid line reported back to the main PCB telling the system to ramp down on the compressor....

I know this an old post but it sounds like the issue was never resolved...

the other thing I find with many of the chinese made multi-splits is that the outdoor unit does not have the capacity to handle all of the indoor units operating at the same time..

to avoid excessive defrost calls or the possibility of condensed refrigerant in the outdoor coil during cold outside temps these units will ramp down the compressor even when multiple indoor units are calling.. this is done to keep the outdoor coil temperature up a bit..

in my opinion thats not right.. if I buy a 12+12 system I should be able to run both indoor units and expect the outdoor to run flat out but many do not have the outdoor coil area to support both indoor units in heat esp at lower ambient temperatures...

-Christopher


Hi Christopher

The indoor units are MV12AH x 2 and the outdoor is an FM25AH. So perfectly matched with both units running.

If only one indoor is calling for heat then full output should be achieved by that unit that is switched on. Instead it drops off unless both indoors are calling for heat we then see good output with air offs off 45C or so.

The issue was never resolved... about a year ago the outdoor PCB was replaced with a new one, this never corrected the issue and it still behaved the same.

You mention the issue of the LEV on the bedroom unit. We observed the same issues if it was the lounge unit at thermostat off and the bedroom unit calling for heat. It does exactly the same, so it could be coincidence that both LEV's are bad? I think not... read on lol...

In October 09, we had a 3rd unit fitted onto the outdoor... a wall mounted unit for our spare bedroom which we rent out. This is also a 3.5kw unit... so of course I understand that if all 3 units are calling for heat this then puts the total of indoor units over capacity for the size of the outdoor unit... and thus it shares its capacity out across all three.

However when all three are calling for heat we get fantastic air off of about 42-44C, if 2 are calling for heat, again good air offs, if only 1 is calling for heat (the new wall mount in the back room) we get air off of 32C. This is if the other two are switched on but at thermo off. In summary when all indoors are calling for heat they work great when only one is, performance is terrible.

Switch all other units off and leave the wall mount on... air off 44C within 5minutes and compressor ramped up further than it would if the other 2 were left on at thermo off. When units are physically switched off I do believe the EEV's shut down to 10% as the coils go noticeably cooler, however they dont seem to follow suite at thermo off.

The wall mount also will not go onto high fan speed, unless the other 2 units are turned off or at least one is calling for heat as the coil never gets above 38C.

Pipe and coil sensors were replaced on the indoor to see if the coil sensors were at fault... they were fine but unit will still not go onto high fan speed under the above conditions... this results in a room that never gets warm because we cant increase fan speed unless the other units are turned off.

So it seems that too much refrigerant is sent to the units that are at thermo off when this refrigerant should be going to the unit that is calling for heat.

So yes to me the eev stays open the same % on all units that are turned on whether at thermo on or thermo off as when the fan comes on periodically to clear the heat build up the air off is the same as on the unit that is thermo on 32/33C.

LG state that it should be 10% on units that are thermo off/off state, however I think if they are turned on or thermo off they remain open the same value they were when they were thermo on/calling for heat. (they dont close down)

Meaning outdoor unit is ramped down to match the load conditions on the system (1 unit operating) but the eev positions do not match.

Obviously I have put a lot of thought into this, a lot of engineer visits who agree, 1 member off the forum visited also. Yet LG still dont want to listen... and try pushing it back onto the installer or the engineer.

As I say the PCB was replaced early last year, the system was installed the year before that so unless they have changed the software on the PCBS since I suspect that things will still be the same.

Really not sure what to do next... you guys agree it isnt controlling right... we all do in fact yet trying to get LG to listen without kicking off is another thing.

I agree LG should be coming out to look at this problem but £300 for an engineer visit and they may just say... its how it was designed to work... im then out of pocket.

There are different versions of this outdoor unit. Mine is the FM25AH UE1 there are version that go upto UE3. If I was to get a UE3 PCB I dont know if the software would be any different or whether it would even work.

There is even a long pipe mode setting which LG advised to switch on yet this does absolutly nothing, engineers have said the pressures dont even increase and the compressor does not step up when this mode is turned on? LG say it increases the frequency for longer pipework which my wall mount is on.

By all means if someone wants to come visit or try to take this up with LG then it would be much appreciated. LG view me as not being an engineer and will not entertain me. Engineers who visit, do not rate LG so when they speak to them they just feel fobbed off by LG.

All in all a pile of $hite! With no ends of problems. The multisplit method is best for me due to outside space and living in a flat etc but NOT LG's multisplit!!! They dont work very well at all.

I await your comments...

Regards
Richard.

[cadillackid]

I totally agree that this is a controls issue.. esp since you can demonstrate that an indoor unit turned completely off does allow the EEV to close correctly... my guess is LG must have some sort of "hot keepalive" feature and that is why the valve stays open more than 10% for units in a thermo-off state....

like others have said 10% is normal for oil return on these... (why they dont just do a periodic oil return cycle I dont know)..

trouble is im across the pond in the USA so im not going to be of much help in this regard....

sure seems to me this is not the way a system would be designed to operate.. in fact the CHigo based multis I have worked on were the opposite of yours.. when all the indoors were calling the system would give mediocre air-off temps....

in your case my guess is that they only allow a certain compressor frequency for a single indoor unit.. not the way I would run a control.. as personally if it were my design I would allow the compressor to run as much as it needed for a single indoor unit to maintain the desired middle pipe temperature on the indoor coil...

when you have just one indoor unit running what is the difference in temp from inlet to outlet (suction to liquid) on the indoor unit?

trouble is if we are fighting a controls issue the only way to fix that is different software.. and I have yet on any of these LG or chigo units to be able to kipe the software from the micro in such a way that I could edit it and burn it back in....and trust me Ive tried as I really hate the control algorithms used on many of these.....

-Christopher

[back2space]

I totally agree that this is a controls issue.. esp since you can demonstrate that an indoor unit turned completely off does allow the EEV to close correctly... my guess is LG must have some sort of "hot keepalive" feature and that is why the valve stays open more than 10% for units in a thermo-off state....

like others have said 10% is normal for oil return on these... (why they dont just do a periodic oil return cycle I dont know)..

trouble is im across the pond in the USA so im not going to be of much help in this regard....

sure seems to me this is not the way a system would be designed to operate.. in fact the CHigo based multis I have worked on were the opposite of yours.. when all the indoors were calling the system would give mediocre air-off temps....

in your case my guess is that they only allow a certain compressor frequency for a single indoor unit.. not the way I would run a control.. as personally if it were my design I would allow the compressor to run as much as it needed for a single indoor unit to maintain the desired middle pipe temperature on the indoor coil...

when you have just one indoor unit running what is the difference in temp from inlet to outlet (suction to liquid) on the indoor unit?

trouble is if we are fighting a controls issue the only way to fix that is different software.. and I have yet on any of these LG or chigo units to be able to kipe the software from the micro in such a way that I could edit it and burn it back in....and trust me Ive tried as I really hate the control algorithms used on many of these.....

-Christopher

Hi Chris

Thanks for your response. The unit also does an oil return cycle every five hours in heating mode, (reverse cycle with compressor at full pelt) for 5 minutes then reverts back to heating.

Not sure of the difference in temperature from inlet to outlet but engineers have assured me it is in range.

The inlet temp is usually the same as those at thermo on as those that are thermo off. But units that are physically off have a lower inlet temp... or whichever way you look at it.

[lomb]

Ive gone for 6 single MHI splits to heat and cool a building with 6 condensors outside (probably a seventh soon). From everything from compressor burnout taking out all the indoor units and pipework to leaks , oil return, control, fault finding, expense with downtime if anything goes wrong i chose this option and im glad i did.
Bsck2Space could you not have just stacked the oudoor units one on top of another? There is generally plenty of space on buildings if gets over the boxy look of the machines and they dont actually look too bad kind of cool actually!

[back2space]

Ive gone for 6 single MHI splits to heat and cool a building with 6 condensors outside (probably a seventh soon). From everything from compressor burnout taking out all the indoor units and pipework to leaks , oil return, control, fault finding, expense with downtime if anything goes wrong i chose this option and im glad i did.
Bsck2Space could you not have just stacked the oudoor units one on top of another? There is generally plenty of space on buildings if gets over the boxy look of the machines and they dont actually look too bad kind of cool actually!

Yeh that could have been an option and yes I would have had better control of the system but the whole thing was done on a budget so installation costs would have been higher if I had gone for 3 separate units.

The system has never broken down touch wood its just the control strategy that seems to be so poor.

Have you any pictures of your installation?

[cadillackid]

I also have installed multiple units.. I originally thought of a multi-split but had also didnt want to lose the whole system if i had issues.. (and i have had issues).. plus in effect i can ramp my house all the way from 5000 BTU all the way up to 51,000 BTU... (on a humid day)... so i can have my quick cool downs AND still keep control of the humidity....

I know ive shown pics of the indoor installs as i was prototyping out my system but i can post a pic of my outdoor units if you like....

of course in my case since I customized the indoor system and have it all integrated into my basement and through the ducts i do not even have the "wall warts" on the inside of the house and no "linehide" going up the outside walls for the high wall mount units...

I know in europe its unusual to have ducted air systems in homes and is normal for people to have splits on the walls.. but it hasnt quite caught on in the USA yet as many people here seem to consider wall mounts or cassettes as "ugly"...

my guess is also that running a Multi-split may be more economical on the budget as each inverter does have some Loss in it so perhaps running 1 compressor might be better than running 3 or 4 even at low speed.. albeit my compressors rarely ever ramp up very high... although yesterday was an exception... it was 86 outside and the dewpoint was 73.. the house was open windows all day and then i got warm and decided to run the air-cond.. for a short while i could hear all 3 compressors whirring away unti it started to bring down the indoor temp and humidity...

I honestly think it is a design fault on the part of LG as it seems all of the OP's hardware is functioning properly.. or it may be an unforeseen fault in the way oil returns to the compressor so they leave the EEV open to keep a flow going...

one of the things im finding out about all of these chinese units is that the manufacturer in china does not typically also make their board-sets.. it is out-sourced... and to keep the costs down low they order thousands and thousands of board-sets from the board-house..

so if there is a software change mid-stream they do not stop the lines, update the software and go, they run out current stock on boards and then go...

they are also very aware of the volatility of the situation as well... say a board house named "FTL" sells 50 thousand boards to Chigo who makes splits for 15 different name plates... first the customers begin complaining to their installer that a unit is wacky... the installer calls the brand name (not chigo).. the brand name tries to shoot the trouble and cant nail it, send new boards, replace parts, etc... finally they contact Chigo about the issue.. the barrier of western-world to china is a bit tough to deal with...

langauge barriers.. an overall fact that china doesnt hold quality to as high standards as western world...

Chigo is not likely going to ever admit that there is a design flaw in their software... why?? because they produce these things so cheaply already there is no $$ left in the deal to open up the flood-gates to all kinds of people that want new board-sets for free.. so they quietly nudge the board maker.. the changes are made, the issue fixed in future production....

my point by thius long boring post?? unloess its a huge MAJOR flaw that makes the unit fail to operate or allows springs and spragues to fly.. you will likely never hear about the fix and it takes a LONG time to make it into the stream.. and thats only if they get enough complaints to warrant getting the board-house to make changes...

that said.. I *am* finding that china is not very good with their software security and that they leave the JTAG port on their ATMEL micros Wide open so chances are the code could be disassembled, reverse engineered and the issue fixed... but I dont guess you or anyone else on this board would want to buy me a unit and then pay my hourly rate to reverse engineer and fix the code... by that time you could fit a mitsi...

-Christopher

[lomb]

Yeh that could have been an option and yes I would have had better control of the system but the whole thing was done on a budget so installation costs would have been higher if I had gone for 3 separate units.

The system has never broken down touch wood its just the control strategy that seems to be so poor.

Have you any pictures of your installation?


Sure, il post when i get a chance. To be honest i think installers prefer multisplits as thats what customers demand and they demand that becase they dont know better and want as few condensers as possible. Efficency wise ive worked out the single splits are cheaper to run. Even vrf units arent as efficient as single splits except when all internal units are running which is rare in the real world. Part of the reason is the compressor is oversized for full load and is thus operating less efficently at part load. Just look at the COPs and how they go down when less internal units are connected(or switched on!)

[back2space]

Efficency wise ive worked out the single splits are cheaper to run. Even vrf units arent as efficient as single splits except when all internal units are running which is rare in the real world. Part of the reason is the compressor is oversized for full load and is thus operating less efficently at part load. Just look at the COPs and how they go down when less internal units are connected(or switched on!)


Really... when I did my sums I worked out that if only one indoor was operating then separate splits was cheaper to run but as soon as you run more than one indoor unit the multi then becomes the more efficient.

As there are certain margin's that each units can ramp down/up to.

If the multi is ramped right down and all indoors are running at minimum duty then you will save more with the multi as you are only running one compressor but if your only running one indoor and the outdoor is ramped right down the larger compressor cannot ramp down as far as a single 1-1 split.

For me separate splits would probably have been the better option as very often I only have one indoor running. Only in the depth of winter do all 3 indoors run at the same time or in the state of thermostat on.

[cadillackid]

here is how I have my units set up outside the back of my house.. they look closer to the house in the pics than they really are.. the spec in the docs for them was 8".. I have them 20" from the back of the house and have killed all the vegetation behind them.. there is plenty of room to work on them...

one of the things I would say against stacking them, is that to service them you usually have to remover the top panel before you can take the front or back off.. and also the electrical box inside often as screws on top that need removed to access the circuit boards...

-Christopher

[lomb]

Really... when I did my sums I worked out that if only one indoor was operating then separate splits was cheaper to run but as soon as you run more than one indoor unit the multi then becomes the more efficient.

As there are certain margin's that each units can ramp down/up to.

If the multi is ramped right down and all indoors are running at minimum duty then you will save more with the multi as you are only running one compressor but if your only running one indoor and the outdoor is ramped right down the larger compressor cannot ramp down as far as a single 1-1 split.

For me separate splits would probably have been the better option as very often I only have one indoor running. Only in the depth of winter do all 3 indoors run at the same time or in the state of thermostat on.

exactly.. but my figures show that if one has a four unit split then the efficency is low even if three internals are running. single splits are definately more efficent than the best VRF systems never mind the day to day multisplits. Also take into account that unless one has a true vrf then one cant heat and cool in seperate rooms at the same time.
Here are some links to COPS on multis as an example
http://www.airconwarehouse.com/acatalog/Monozone-Multizone.pdf
page 30ish. Additionally note hitachis basic single split gives a cop of nearly 4. I remember looking at a daikin multi 5MXS90E and the difference was even more stark.What was A efficency with all the inners running turned out to be D or E with 1 connected .

[lomb]

The only efficency disadvantage of seperate splits is the standby current and crankcase heaters but this is only about 50 or so quid a year versus say 20 with 2 multis on 6 splits a small price to pay for the advantages.

[cadillackid]

I also like having multiple units because of the true 'variable speed" i can get in my house... in the setup I showed above.. I have 5000 BTU all the way to 51,000 BTU at my disposal all inclusive...

oh and the fact if one dies my whole house is not down.. i still have 2 others that can really make up the difference... with my systems being centrally ducted I can tell the computer to re-direct the electronic dampers such that it pushes conditioned air from one room to the other in the event of a failure....

the only thing I cannot d is close the supply damper of an operating unit.. thats a very bad thing....
-Christopher

[back2space]

sorry ive ben a bit busy, changed my name im no longer hendrag but still doing the blogs

hope you like em

graham

Hope we like what? LG no!

[back2space]

I know this is an old post but just to highlight how long these problems have been going on for as I am sending an email to LG requesting that they send one of their engineers.

I cant believe this has gone on for nearlly 3 yrs.