Some beginner questions on split units.

[raz5]

for a small split install you should be getting below 500 microns after 30 mins with a good pump and new oil using 1/4 and 3/8 lines. how long is it taking to get down to 300 ?? have you any schrader valves uncapped on your gauges ??

[Reptile]

for a small split install you should be getting below 500 microns after 30 mins with a good pump and new oil using 1/4 and 3/8 lines. how long is it taking to get down to 300 ?? have you any shrader valves uncapped on your gauges ??

Yeah - about half an hour to get there I guess. 350-400 across all installs. Not sure what a Shrader valve is !? Got a 1/4" to 5/8" adapter onto the service valve

I'm not being an ass, but can you confirm that I'm not doing anything wrong?

I really think the lines of my manifold gauges that I have to use to vac are leaking at deep vacuum?

[raz5]

schrader valves are used a lot in splits and fridges on the service ports . they are the valves you have on tyres for want of a better description but they hate a vacuum as they work on positive not negative pressure . Some manifolds have these little buggers on the ports so make sure if you have em on yours the caps are on and tight .. yep they have caught me out in the past during a vac

[Reptile]

My manifold has 3 ports at the bottom, and 2 at either side that have no holes (guessing a higher model of same unit might have these open?) Also one in the middle with a metal cap. The ones at the bottom have plastic covers which I dont imagine would keep a vac, but they are never active as the high side port is always closed, and the low and middle are always in use.

What about the 'schrader' vales on the other 2 unused ports of the vac pump? they seem a likely candidate as a weak link... mind you I isolate these by winding in the pump handle don't I?

[raz5]

My manifold has 3 ports at the bottom, and 2 at either side that have no holes (guessing a higher model of same unit might have these open?) Also one in the middle with a metal cap. The ones at the bottom have plastic covers which I dont imagine would keep a vac, but they are never active as the high side port is always closed, and the low and middle are always in use.

What about the 'schrader' vales on the other 2 unused ports of the vac pump? they seem a likely candidate as a weak link... mind you I isolate these by winding in the pump handle don't I?

the 2 ports on the side of the manifold are used to attach the floating ends of your hoses to prevent contamination while not in use
What is model is your vac pump ?? any exposed schrader under vac will be a source of failure . Cap the blighters as they will stuff your vac up

[nike123]

Not sure on most of those, but its a modern house and it is not tripping the RCD. It is a UK pump, new.

Changed the oil (even though it had only done 1 evac), and it was still doing it later on when the sun had gone. Tripped after 15 mins, shut down, obviously reduced vac as the line was still open, and then restarted itself after 5 mins! Was too hot to touch.

Is that knackered too? Still confused about the vacuuming. Exactly the same symptoms on all 3 of mine.

I don't think I'm doing anything wrong, but for the sake of it, I'll detail it. Not that I expect any responses, either that or I'll make an utter berk of myself - maybe Brian will reply then

I always start by opening the little knob thing for 2 mins, then closing. Vac for 1 hour or so. Using the 1/4" port on the pump that fits my pipes... other 2 capped with plastic cap things... winding handle fully open... Using various pipes - tried them all, mainly pipes from my manifold / nitrogen kit. All installs fully pressure tested.

Using any of the following:

Method 1: Vac pump to centre port of manifold, high side closed, low side open. Low side port to "vac" port of VG64. "aux" port of VG64 (inline) to service valve of outdoor unit.

Method 2: Vac pump to centre port of manifold, high side closed, low side open. Low side port to service valve of outdoor unit. VG64 "vac" port connected to extra port on centre port of manifold (not inline).

Method 3: Vac pump to VG64 (inline) to service valve of outdoor unit.

All methods get down to 300-400 microns and then stop. But wind the pump in, with it still running, and it shoots up to 1000-1200 microns, no matter how long its been going. Then it rises very slowly - 50 microns every few mins.

How on earth do people get it to hold 500 microns?

As I say, tested my pump just to the "vac" port of the VG64, and it does exactly the same, so nothing to do with my installs I'm guessing.

Done now anyway.... but would still like to know.

Regards



Monkeyspanners, I would suspect heat, but it happened later on too, in the shade. Don't fancy another forum battle now, its done anyway. Whenever it happened it vac'd right back down to circa 350 anyway... :s

You got answer to these questions 3 days ago:

http://www.refrigeration-engineer.co...07&postcount=5

[Reptile]

Raz - not sure what you mean by exposed - sorry. They are covered right now by the screw on plastic caps attached to to the vac pump. Kinda like the valves on car tyres. Are you saying I should replace these with metal caps? Doesn;t explain why my vac would jump up even when these are isolated with the wind in handle though !?

Its a mastercool 142lpm pump.

You got answer to these questions 3 days ago:

http://www.refrigeration-engineer.co...07&postcount=5

Nike - thanks again for your response... you are the most consistent helper of newbs on here !
I did read these links, not that they made much sense... and if you notice I have consistently referred to the fact that the pipes not being up to a vac is the most likely cause... (?) ... but still, trying to make sure I've not RS'd it up!

Read so may posts about people vac'ing with manifold gauges, so me using these lines surely can't explain it? Or can it? If so, everyone else must not be using a micron gague !? Or my manifold is particularly crap!

ps. why's it cutting out?

[nick uk]

hi reptile is vac pump set for the correct voltage ?

[Reptile]

Hi

There is nothing on it that I can change - no switches or anything, so guess so.

Cheers

[raz5]

Its odd that the pump keeps cutting out . I have left mine running for hours on big systems and triple vac without any probs as long as there is sufficient airflow around the pump , they do get warm like all motors but they are designed to run for a while . The fact you are getting a vac to 300 is good enough infact anything below 1000 is adequate in splits. If you have leak and pressure tested without probs using ofn I would be looking at your hose connections as they can be a source of problems in a vac situation as they prefer positive pressure . if your sure there are no leaks on pressure test then once you have pulled 300 close the manifold port with the vac connected and let the charge into the system . No need to let it sit in vac state longer than nesc . all I can stress is check you have no leaks when pressure testing with ofn or helium (helium is ideal as the molecules are even smaller than ofn but it is 3 times the price !! ) and let it sit with test pressure for 24hrs to be sure and confident you have no leaks then vac and release the charge . Hope this makes sense.

[moondawn]

Hi There My Vac Pump Has cut out before, mine was using 110volts and the extension lead was not fully wound off the reel.
the cable resistance increases and the pump trips.

I always now reel off the 30 metre coil of extension lead when using 110volt power

thanks lee

[nike123]

Hi

There is nothing on it that I can change - no switches or anything, so guess so.

Cheers

What is pump running ampere?
What is pump nameplate FLA?
What is oil type in pump? Is it Vacuum pump dedicated?

[Reptile]

Nike

It is 3.6 / 3.0 A

No idea what an FLA is sorry.

Yep - its on fresh vac oil from RACS, which I assume is fine.

Cheers

[nike123]

Nike

It is 3.6 / 3.0 A

What is what here?

No idea what an FLA is sorry.

FLA is full load amperage. It is max operating amperage stated at motor nameplate.
By your motor power (1/3 hp) it should be max 3,6A.

[Reptile]

Honestly Nike I've no idea what it means - its just what is printed on the label of the pump. I'm putting the cutting out down to overheating of the unit, as it was ridiculously hot when it did it.

Anyway, for now at least its a secondary issue, as my 3 units are installed...

Can I ask about a new issue...

Why do they stink when not cooling? I've got digital thermometers monitoring room and output temps... and when it is in fan mode, or in cool but the room is at required temp, it stinks of old socks. I've read about old sock syndrome, but 3 units, all a week old? Its not good - not just directly in front of it but it stinks the whole room. I had high hopes of running these all summer and just letting the system work its magic, but at this rate, no chance.

Can you not just have it cooling until its needs to cool no more, then shut down? Why does it need to blow smelly room temp air through it when not cooling?

It has not been subject (in its short life) to perfumes, smoke, pets, anything really - maybe one or two guffs. Modern house, no damp... would having the windows open a crack help any? Seems to defeat the point. Have got all 3 tonight running in fan mode for 5 hours on sleep timer. Have never used heat mode.

Grump!

[mikeref]

Interesting thread. I wonder if you did all the wiring yourself as well? I've been dragged over the coals in the past for connecting indoor to outdoor unit only, not a/c to mains. Must have dual trade to fully install a/c here legally, but a competant D.I.Y.er might get away with it only untill something goes wrong, like injury or death then you have a truckload of trouble at the frontdoor, but i guess you've anticipated all possibilities for your neck of the woods.. cheers.. mike

[Reptile]

No I didn't. But thanks for the useful input Mike. Any comments on why it smells?

Regards
Reptile.

[sumsor]

Karma?
Haha, you have to admit that's funny!
Where are your drains connected to?

[Reptile]

Karma for what?

My drains drain out generally into open air... some via extenders, some via straight pipes... but all just fent to open air.

Don't get me wrong, it doesn't stink, just if you stand in front of it when its recirculating room air, not cooling, it smells of socks... perhaps its normal...

[exotiic]

Don't get me wrong, it doesn't stink, just if you stand in front of it when its recirculating room air, not cooling, it smells of socks... perhaps its normal...

Definitely not normal

[lawrence1]

It's the installation that stinks.
Call MHI for a warranty service call,,,tell them the full saga of this installation and i'm sure they will sort it out.

[Reptile]

Thanks for the opinion Skippy. We'll have to see how they are tonight after being run on fan only all day.

[Contactor]

Your units have been colonised by bacteria, it doesn't take them long once they get going. The cold air knocks them back a bit, you need to buy a chemicasl spray to kill them off.

[Contactor]

How many women have you got on the go there, perfumes and cosmetics are the main source of organic cpompounds for the bacteria to feed on....

[Reptile]

I occasionally wear some depending on what mood I'm in. But not since the install.

After sniffing it again tonight, I'm thinking it might be a plasticy smell, kinda of a 'new' smell, but not a particularly nice one.

They've never been on heat - do you think an hours blast on heat will help?

Finding it hard to believe bacteria have taking residence after a couple of days only.

[monkey spanners]

Get some 'Condencide' coil cleaner, follow the instructions and spray the coil and keep it wet for ten minutes then run the unit in cooling so that the moisture on the coil will rinse the chemicla off.
You can get 1L ready mixed or 5L you need to dilute and spray with something like a pump up garden sprayer.

Welcome to our world...

Jon

[Reptile]

Thanks - I will look into that - although i can only find the 5L at my new favourite supplier

But... after only 2 days !?!?!? And all all the units??
Are you sure?
Also, how come it is just when it is not cooling?

Sure I will need to do this at some point, but it just seems a little premature. I'm gonna stick then in heat mode for an hour, but only when i've gone to bed, as I'm cold blooded.

[Contactor]

It can only be bacteria, the cold air stops them making the smell.

[Reptile]

It can only be bacteria, the cold air stops them making the smell.

Thanks Contractor.... you are very helpful.

I hear you, but still, 2 days... come on...

If its bacteria after 2 days I'm going to be mightily miffed. No pets, smoke, perfume, anything... well I do really like a trump - could that affect it? Seriously?
It does seem premature (no pun intended Lawrence)

I will buy some of that stuff... but I'm buggered (again, no pun intended Lawrence) if I'm going to spray it every two days.

I'm finding it quite uncomftable to sit under at the moment. Even with the jets directed away from me the difference between the 8 degrees it blows (no) and the 22 degrees of the room is very noticable. Is it so cold because I was so maticulous in the installation?

[Gary]

Are your drains trapped? When you shut off the fan does water come gushing out of the drain?

[Reptile]

Hi.

No. My drains are not trapped. Should they be? I did read just yesterday about trapping drains. Mine just vent straight out to fresh air. One is just the unit pipe, one uses a flexible drain extender and one uses solid overflow pipe.

By trapping I am effectively creating a u-bend like a toilet? Why/how would that help odour? Would it not retain more moisture than it removed? I oculd understand it if my drains drained to a sewer or something... but just onto the gravel of my driveway...

Its probably something obvious I've done wrong!


Cheers

[Reptile]

ps, I have never tested the fan/gushing issue... I'm guessing not - why would it !?

[Gary]

Often the drain is on the suction side of the fan. Air is sucked up through the drain line, preventing the water from draining properly. A trap allows gravity drain. If the water comes gushing out when the fan shuts off, that's a dead giveaway. It means the fan is holding in the water.

[Reptile]

Blimey - that made sense.

I'll test it tomorrow. In a way I hope its not that, as its all installed neatly in trunking now. But, you lives you learns....

Cheers !

[Reptile]

ps, you're not a million miles away from my second home - but I think I'll leave that one to the pro's !
(Northport, Sarasota)

[Gary]

Blimey - that made sense.

I'll test it tomorrow. In a way I hope its not that, as its all installed neatly in trunking now. But, you lives you learns....

Cheers !

The trap can be installed on either end of the drain line... or anywhere in between.

[mikeref]

No I didn't. But thanks for the useful input Mike. Any comments on why it smells?

Regards
Reptile.

Maybe all 3 a/c,s smell because of residual oil on evaporator fan motors. Eh, what size(kw) are these units and what about insulation, how good are are you at home insulation? Any schemes/rebates going on over there?.. mike.

[nike123]

Drain pan is at exhaust side of fan and it should not be any trap in drain line as it is noted in instalation manual.
Some smells are from new equipment and plastic could smell badly for some time (some ABS plastic is pretty smelly). Leave it as it is for 2-3 weeks and see if smell is weaken.

[spimps]

Local customer bought two splits from a green grocer friend of his who was closing down for his wife's dress shop,not your ordinary shop,all ball gowns and wedding desses at £800 plus (wife goes to charity shop!).Tried to convince to put new in but no he wouldn't budge so installed his second hand units after some considerable effort with compressed air to remove dust from indoor units,just as well as they would have ruined some stock (ceiling/cassettes).Although not dusty when fitted they made the shop smell like the inside of a potato sack .Popped a smellie jelly in each and now smells of prawn ****tails after the lemon is squeezed in.
Worth a look at the smellies as some folks are far more sensitive to odours than others,there often can be a slight pungent smell when shutting down units from ac,although at a few days old it's surprising with yours.http://http://www.ryanairconspares.c...esh-p-164.html
Worth looking at the amount of condensation you are removing per hour,is it an old house,damp proof etc this can all add to the amount of water exiting the drain.

[nike123]

Also, since this is DIY job and some beginner errors are most likely, it is worth to look that, in any time and mode of operation, drain pan is not flooded. It must be drained all the time and only covered with dripped water and not filled to any level. Failure here led to premature and excessive growth of algae and fungi.
Therefore indoor unit must sit perfectly horizontal or sloped slightly in direction of drain outlet.

If that doesn't help than put 2 tablets of AC-TABS from Rectorseal in drain pan.

[Reptile]

I will be checking the drains on all my units asap, but I did slope each indoor unit towards the drain side slightly. I also made sure to get a good angle on the holes through the wall.

The only grey area for me is the one that went through an external wall... as with the flare pipes, the drain pipe stuck out by only an inch or so, meaning I had to bend it quite significantly into an extender pipe. That is the only area I could potentially see a blockage... I did double check it at the time, and it is visibly draining, but i will double check by tipping water into the unit tonight.

Thankyou

[ktm]

I have left my pumps running for days and I can pull systems down to almost 250. U didn't put any pressure down into your pump? Oh well done on your install. U seem to have your head screwed on possibly more than some of the qualified people I have come across.

[Reptile]

Just a follow up to this. The smell is getting better. One seems worse than the other 2 (which incidentally has the most complex drain run).

It is fine on cooling, or drying mode. But when it is just cycling, it is blowing out humid air which I think is the issue.

I know it is doing this as I've got a digital thermometers / hygrometers monitoring things. When it is cooling the humidity of the room drops, when it is cycling, the humidity rises, and the humidity of the direct air flow is particularly high. This can be seen on the louvre blades too, in the form of mild condensation.

My drains are definately draining, and clear, all angled downwards, and all units are very slightly sloped to the drain side. I've read of this behaviour on other threads.

Clearly there is going to residual water on the fins after a cooling cycle, so i'm guessing this is then being blown out in the air stream when cycling. I woke up to 85% RH in the bedroom this morning, as it was just cycling 22 degrees all night. The rest of the house was 65%

Ideally it needs to cut out when temp is reached. I suppose this could be done by wiring in a room based thermomostat, but guessing it would not do the compressor any good being cut and restarted!

Just after comments - am I using it too much? Maybe because it is not warm outside this is causing my issue. I'm more just testing then anything.

Cheers

[Gary]

You might try a low fan setting. Generally, high fan speed is more efficient while low fan speed removes more moisture.

[Gary]

I woke up to 85% RH in the bedroom this morning, as it was just cycling 22 degrees all night. The rest of the house was 65%.

I find this puzzling. Given a room temp of 22C and evap air off temp of 8C, I would expect the humidity to be down around 40%.

Of course, this assumes the unit runs long enough to remove the moisture. Possibly these units are oversized?

[Reptile]

I was going to say, I think the bedroom one may well be oversized unfortunately. I do run on lowest fan setting though! I oversized 'deliberately' for many reasons - not least of all that I thought it could cool the entire upper floor on hot days!

The 8 degree air is only when on cooling cycle in high temp room. Normally 11 or 12 degrees on a low cool.

The problem comes when it is just cycling room air. I also think this is the slight odour I refer to. I could understand it not removing moisture in this case, but to increase it seems odd.

I'm just going to stop using it when it is not needed, testing it, and wait for summer

[back2space]

It has not been subject (in its short life) to perfumes, smoke, pets, anything really - maybe one or two guffs. Modern house, no damp... would having the windows open a crack help any? Seems to defeat the point. Have got all 3 tonight running in fan mode for 5 hours on sleep timer. Have never used heat mode.

Grump!

I leave my windows open on the catch when the a/c is on just to let some fresh air in.

I find my units have that sweaty smell about them when they have been in the bedroom over nght where the air gets stale or again in any room where the air is getting stale.

As the unit cools water from the air condenses on the coil inside, so for example your breath and other smells in the room could be cooking smells for instance will be contained in the moisture. This condenses on the coil and if the system doesnt run for long enough the odours dont get chance to be flushed away and the smell you can smell is basically the moisture coming off the coil and back into the air.

I find that if the unit is running for longer on hotter days the moisture contianing odours gradually is removed and flushed down the drain, having some fresh air coming into the room speeds up that process.

This is different from the cat wee smell that a lot of people report, this is down to a combination of bacteria growth from when the unit is turned off and the coil is still wet (best to run the fan mode for an hour at the end of the day) and manufactured smells like perfumes, building fabric smells, cooking smells etc. These gradually build up on the coil and is nessasary to clean the coils with specialist cleaner.

The reason this doesnt happen in heating mode is because the coil is warm and there is no condensing going on. IN heating mode the unit doesnt remove moisture.

Just after comments - am I using it too much? Maybe because it is not warm outside this is causing my issue. I'm more just testing then anything.

Cheers

I have wall mounts in my flat and experience the same smells when outdoor temps are not that high as the unit is not running so much.

The moisture that is removed contains smells etc each time you sweat, breath out even fart lol! THis moisture then condenses on the coil and as long as the compressor is keeping that coil cold fresh smell free air will be released from the air outlet. THe longer that cycle runs the room is going to slowly start contianing less and less smells so any more moisture removed from the air gradually rinses the smell from the coil. Short cooling cycles dont allow this to happen. Im talking about natural smells obviously perfumes/deodorants can leave a build up on the coil which is harder to remove.

The longer the cooling cycle runs the more moisture it is going to remove and gradually those smells that have built up on the coil will be removed as the air in the room dries out. The ambient temperature and outdoor temp is also an issue that I have found with my units being oversized for the rooms (which was done for heating purposes) they reach set point quickly even on low fan speed so the bit of moisture that has built up on the coil will contain your breath etc and then when it cycles off at room temperature the moisture that collected on the coil will evaporate back off the coil and leave the smell behind... ive likened the smell to a sweaty sock/vinegar smell before! Its just something you will have to get used to unless you are going to install a heat recovery ventilation fan to ensure the air is changed regulary in the room.

Another tip... sure that when you have finished with the units for the day, run the fan mode for an hour you can set the sleep timer on fan mode so that the unit dries out, this is how bacteria growth starts from the coils being left damp and the bacteria will grow.

You think your units smell you should have smelt the fujitsu cassette units in the nightclub I used to work at that would reach set point as the club had emptied and we was clearing out! THey stank of all those sweaty ppl that had been dancing, all the drinks that had been spilt on the carpets etc the smells would be sucked into the unit during the night then when it had reached set point because the club was empty the units stunk!!!!

You also refer to feeling very cold from the air that is coming from the unit, this also sounds like your units are oversized to the rooms - as mine are, they were mainly put in for heating and cooling is a bonus really but we oversized them as then we can run them on low fan speed and are probably then running at design conditions for heating... still even low fan speed is too much output for cooling.

Best way to resolve the cold draught issue from the unit is to manually by hand move the louvre that opens and closes and partially close it... this then slows the air velocity at which exits the unit. Obviously dont shut it too far but make sure it is angled horizontal as my wall mounts by default have the airflow angled slightly downwards in cooling so if you are in line of the unit you get blasted by the cold air.

[back2space]

Hope that helps a bit

[Deniver45]

Hi all

I have just put in my first MHI split unit, which went well overall, but I have a few questions which I'm not going to find in the documentation, so thought I'd keep them all together in one place. Apologies if they are a bit random or daft.

1) In the evacuation process I had my digital gauge inline inbetween the manifold low-side and service valve, and the pump in to the centre port of the manifold. I had to see positive pressure when releasing the gas before I could remove my gauge, and lost some gas in the meantime. What is the best configuration and process to use when evacuating? (idiots guide). Should I have my gauge tapped into my manifold instead just using one port on it (ie not 'inline')?

2) Related to the above... I was seeing 300 microns with the pump running, but isolate the pump and that quickly rose (within 1 minute) to 1000 where it settled and didn't rise. I evacuated for another 3 hours and this was still the same, so figured it was fine, as it was a lengthy pipe run. I was careful to keep the caps on the pipes when installing and it pressure tested fine. Is this normal behaviour, or have I been too hasty in releasing the gas?

3) I know it will change according to many factors, but roughly what pressure should I be seeing on my manifold low-side when all the gas is released into the system? Just as a peace-of-mind check.

4) I couldn't find imperial sized insulation. For 1/4" (6.35mm) and 3/8" (9.52mm) copper I ordered 6mm and 10mm armaflex. The 6mm fits great, but the 10mm is pretty loose on the pipe. A bit concerned it will not be effective !?

5) Insulation again - how far up into the indoor unit do you insulate with armaflex? My indoor unit came with both pipes held loosely together in some sort of foam. I installed it as-was and then stripped what I could off the pipework that was external, and replaced with armaflex up to the hole in the wall, but the internal pipe is still just loose in the original stuff.

6) Last one - I did have to re-do the flare a few times to get it to seal. Eventually I just nipped it up a bit extra on the torque wrench, and this worked. Especially on the 1/4". I have the proper eccentric 410a tool and oiled the outside of the flare, but when the tool completes a flare it leaves 'ridges' in the copper at 180 and 360 degrees, where it snaps off when it is done. Could this be causing a problem? Or do you generally just need an extra turn on the wrench (18 & 42 nm I think it was).

Cheers

Reptile

If you're pulling 300 microns, you STOOD a good chance that you boiled out some of the compressors OIL!

500 microns is fine, but at the beginning you stated you lost your vacuum?

ALSO: as the ambient temp changes, so will your readings. EVERY unit has different head pressures and suction pressures, and again they CHANGE as the ambient temp changes.

I wont EVEN mention what is called "super heat" to you.

How can I say this without insulting you?

I don't think you should be on a NEW unit with these questions.

Pull the Camaro under a tree; crank out the Buds and tune her up!

[exotiic]

If you're pulling 300 microns, you STOOD a good chance that you boiled out some of the compressors OIL!

When you are pulling a vacuum you are not accessing the compressor, the line is closed and you are evacuating moisture from the head unit and interconnecting lines are you not?