low gas?(freezing evap)

[airconadam]

hi fellas ihave been to a unit recently well a number of times along with other engineers and the indoor unit freezes up really bad and i mean bad couple on inch thick with ice now ihave not got the details for it as of yet but its hitachi with 2 indoor casettes its on r22 and 11.5kg charge, so the unit would run for a few days with air on at 24 and air off between 4 and 8oc which would all seem to be fine but then we get the freezing problem another engineer went back to the unit and reclaimed the refrigerant and only got 7kg out now iam just wondering could this be the prob to the freezing up of the indoors??? He also left in under pressure and i have been back today after a few days under pressure with ofn and its not lost a thing so no leak there. So i recharged and ran the unit up and it works perfectly but after a week will it freeze again or will it of been the low gas?? so does low gas cause this unit to freeze and if not what do you think it is thanks alot.

adam

[taz24]

So i recharged and ran the unit up and it works perfectly but after a week will it freeze again or will it of been the low gas?? so does low gas cause this unit to freeze and if not what do you think it is thanks alot.

adam

Systems that are short of gas do freeze the evap up.
It is a very common problem.

The reason the evap ices up is because there is a lower pressure in the evap because the system is not charged correctly.
Because of the low pressure the saturation temp of the liquid in the evap lowers and this lower temp causes moisture to then freeze on the evap.

Cheers taz.

[LRAC]

Is this a master and slave system on one outdoor unit and if it is are both indoor units icing up. the information will help out.

Regards
Lrac

[airconadam]

yer 2 indoor units on one outdoor in a master and slave situation, and yes both units freeze up along with the suction all the way to the compressor

thanks alot

adam

[taz24]

yer 2 indoor units on one outdoor in a master and slave situation, and yes both units freeze up along with the suction all the way to the compressor

thanks alot

adam

No the suction should not freeze up.
If it is short of gas the first part of the evap freeze's up but the rest of the coil and the suction line should be free of.
If your suction is freezing up its not short of gas.
It can't be if your think about it

Check for other faults.

Cheers taz.

[Brian_UK]

I would disagree there Taz.

Once the coil has started freezing up then they will/can turn into a block of ice. The gas pressure/temperature has dropped and hasn't any work to do so will move outside the coil and start expanding in the pipework.

It may not be 'fully ice' type cooling but the lower pressure/temperature will naturally cause the pipework to freeze as they are below dew point.


(I think )

[Gary]

hi fellas ihave been to a unit recently well a number of times along with other engineers and the indoor unit freezes up really bad and i mean bad couple on inch thick with ice now ihave not got the details for it as of yet but its hitachi with 2 indoor casettes its on r22 and 11.5kg charge, so the unit would run for a few days with air on at 24 and air off between 4 and 8oc which would all seem to be fine but then we get the freezing problem another engineer went back to the unit and reclaimed the refrigerant and only got 7kg out now iam just wondering could this be the prob to the freezing up of the indoors??? He also left in under pressure and i have been back today after a few days under pressure with ofn and its not lost a thing so no leak there. So i recharged and ran the unit up and it works perfectly but after a week will it freeze again or will it of been the low gas?? so does low gas cause this unit to freeze and if not what do you think it is thanks alot.

adam

24C/75F - 4C/39F = 20K/36F dT

I have no experience with mini-splits, but this delta-T seems excessive to me. On a conventional A/C, I would expect an evaporator dT of 14.5K/26F or less even for the high efficiency systems and considerably lower for a lower efficiency/older system.

I would say the evaporator airflow is way too low.

[LRAC]

I would start at the basics on these units, 1st set the temp high on the controller and see if it actually switches off the outdoor unit?

Clean the indoor coils and check the motors increase or decrease with the fan speed setting?

Check the twin condensor fans are actually controlling off the fan speed controller. Excess subcooling?

The air on and air off temperatures don't seem right.

I don't think this is a refrigerent problem.

Regards
Lrac

[Ian Neill]

Hello, sounds like short on gas ....I have seen this a few times before on high wall units.. How have you calculated the charge ie pipe run, twin split etc .was the charge wieghed in using scales

[lana]

Hi Adam

Why don't you measure super heat? This will tell whats wrong.

If super heat is high then look for three reasons :
1- Lack of refrigerant
2- Lack of expansion device capacity.
3- Pre-expansion in the liquid line.

If super heat is low then only there is one problem :
1- Lack of evaporator capacity.

This is the easiest way to diagnose.

Cheers

[old time fridgy]

It does sound like a short of gas problem but as previously mentioned does it cut out if the temperature is raised, is the heat load in the room excessive, whier is the temperature sensor, on the indoor unit or on the remote controller and one of the main causes for icing up in the UK does the condensor have a low ambient kit (head pressure controller/fan speed controller). As with most problems it is difficult to assess unless you have got your gauges on and checking temperatures and superheat etc. Hope the engineer who did the reclaiming had their safe handling certificate and the company was registered for hazordous waste and you had an qualified electrician at hand to switch the unit on and off and you filled in any relevant paperwork, hot work permits, working at heights, your tools had been calibrated and most important after all this you remembered to put some money in the parking meter so you can eventually get around to actually fixing the system.

[Gary]

The air on and air off temperatures don't seem right.

Regards
Lrac

What temperatures would you consider normal/low/high for this type of system?

[coolments]

Hi

On this particular system i would be looking for around 9 to 11 DT across this coil in cooling (most AC around this mark taking average from the hundreds of commissioning sheets I have filled in). 24c air on and 4c to 8c air off is massive difference. I also would be looking at low air flow problems, is the evap coils choked up...!!!

[frank]

The compressor contactor is welded and keeps the compressor running 24/7.

Classic symptom.

[US Iceman]

The Compressor contactor is welded and keeps the Compressor running 24/7.

Come on Frank, that is too easy.

Although it is probably close to the truth. Guys, there is an important lesson here... Check the easy stuff first!

[marc5180]

Hi Guys, i had also been called to this unit previously. Model number Hitatchi Rci 5H5QE. There are 2 seperate units in the room each unit consists of 1 condensor and 2 indoors so 4 cassettes in total. The problem was that one of the systems was freezing up causing water to drip on the servers and batteries below.. checked all the obvious signs indoor fans working, sensors, clean coils and filters etc....
when we first got called to it i tried to switch it off by the controller but it didnt switch off the condensor or compreesor for some reason, i couldnt get the cover off the condensor and tried to tap the cover to get it off which resulted in the condensor and compressor going off( which made me look at the contactor first of all) but it seemed ok...wasnt welded in and seemed to operate fine.... I got on the phone to hitatchi who suggested looking at the sensors on both indoors which were all reaing ok. I spent 2 days with an electrician going through the sensors and checking the indoor wiring and dipswitches which were all deemed as they should be. Both indoors seemed to be bringing the room down to spec then the cooling would go off then come back on and go off etc etc so all was as it should be....the air off was anywhere between 10DegC and 2degC with an air on of anywhere between 22Degc and 28Degc. Whereas the other system that is in the room stays on all the time constantly cooling and holding the room, whereas this system is on, off, on, off constantly. That was last tuesday, i then went back monday morning and the guy on site said it had never run so well, but then we got a call saying it had frozen up again on wednesday ( so it had lasted a week ) We took the gas out and recovered 7KG when the system should be charged with 11.5KG....So we pressure tested it over night and didnt lose anything so we then vacced out and recharged... Only to get a call again today that it had frozen up again... The guys from hitatchi are baffled as are we????

[airconadam]

hi again fellas well i wil list a few answers to thos questions, first the gas charge i weighed in using scales of 11.5kg as is stated on the unit and also spoke to hitachi about the piperun lenght etc, now i got a call at 3pm today that the 2 casettes had froze again icouldnt beleive it (both evaps) the customer had turned the unit of on the outdoor and left it of when i arrived i turned everything back on and it ran fine now, in the same room we have got an identical system and when looking on the controller through all the codes etc air on and off are the same as long with a number of other sensors etc even hitachi are baffled to tell you the truth all the air flows are fine on the indoors and outdoors its as if the outdoor unit gets jammed on cooling but iam never ther to witness this. Ialso wanted to know if the customer switched the unit off on the controller did it turn the outdoor of or did it keep running maybe its a comunication error any help always welcome and please ask questions

thanks alot
adam

[LRAC]

I still say its not the refrigerant charge, next time don't hit it till you've got the covers off. I've seen somewhere that wacking the crap out of it normally works.

You say that 4 indoor units are installed in total, on the Hitachi controller has it got a remote temperature sensor or the existing unit probes.

Raise the set point to + 30 C if it doesn't switch off its still electrical.

Sorry mate
Lrac

[marc5180]

The units are cooling only and no they dont have a remote temperature sensor, we looked into changing the return air sensor so they sensed from the remote controller but this model cannot do this, so its return air sensor is where it should be...underneath the evap fan

[airconadam]

its 2 seperate systems eg 1 outdoor does 2 casettes and then another outdoor does another 2 casettes so we have got something to compare it to if u understand it both 2 identical systems

[stevo]

Why not replace the contactor (or swap it with the other identical unit if you haven't got one ! ) i have had this on a wall mount where relay/contactor checks out OK, but seemed to have sticky contacts ! and iced up again after a few days ! worth a try ! (don't think it is a refrigerant problem IMHO ).... good luck

[Brian_UK]

OK, a bit off the wall with this idea but....

In the past the gas charge has been low, you've pressured tested without finding a leak.

Check the charge again and when you've finished paint some clear nail varnish on the access ports so that a semi-invisible anti-tamper seal is created.

You might be suffering from local vandals, a dissatisfied employee or a local fridgy who needs some gas for a job.

You may laugh, but you never know these days.

[marc5180]

OK, a bit off the wall with this idea but....

In the past the gas charge has been low, you've pressured tested without finding a leak.

Check the charge again and when you've finished paint some clear nail varnish on the access ports so that a semi-invisible anti-tamper seal is created.

You might be suffering from local vandals, a dissatisfied employee or a local fridgy who needs some gas for a job.

You may laugh, but you never know these days.

The condensor are in a locked compound high level, there no way vandals could get in or over the wall..

[Brian_UK]

The condensor are in a locked compound high level, there no way vandals could get in or over the wall..

Damn it shot down in flames again

[airconadam]

nah no chance any one can get into the compound its under 24/7 lock and key with cameras all over the site but iam sure things like that do happen iam more tempted to do as stevo has said change the contactor thanks alot guys

adam

[marc5180]

the contactor isnt welded in though and weve excercised the contactor several times and all seems ok.... but maybe it only sticks every once in a while.... its just strange that it seems to goo off on a falut when weve gone home

[coolments]

Ok long shot

its not cross wired is it, have you traced the pipe work from each condenser to its indoor units and belled out the wires. I have seen units run for years like this with out any one noticing untill a problem crops up as no fault codes will show for this, believe me we have taken over a contract with more than 1000 of these units on maintenance contract at the minute and still keep finding units cross wired (dodgy installers).

Assuming 1 system does one side of the room and one the other, originally one of the two systems was more than adequate to cool the room down when first installed so cross wires still made units cut in and out nicely as room always got to temp which ever condenser ran. Suddeny more IT kit is put in the server room so more demand on kit and one system will not acheive set point any more, say left hand of room gets to temp and turns its condenser off but it is actually the right hand right side of the room that looses cooling.

Try to get your head round this, this causes the units on the left to run just about continuous as the right hand side of the room gets warmer, while the left hand side is cutting in and out cooling to the right on thermostat topping up on cooling, phew as good as the explanation will get after beer and kebabs..!!

We had this happen a few weeks ago, no faults codes at all, might not be the same for you but worth checking...Good luck.

Also, cassettes in a server room, not a good idea, its not will an AC unit leak water its when. From the model code you give i see they are R22 and upto ten years old, maybe talk the customer into some new kit, waiting list on parts for these units in summer is bad, especially compressors. They must be ready to chuck a seven any time now.

[Gary]

Given the numbers supplied by coolments, there is no doubt in my mind that this system has an airflow problem. If the identical system has similar evap dT, then both systems have airflow problems.

The question then is not, "Why is this system freezing?" but rather, "Why is the other system NOT freezing?". Is there some sort of automatic defrost mode? Perhaps a low pressure or low temperature switch that shuts the compressor off and allows the coils to defrost?

There are only two ways to increase the delta-T: Increase the compressor capacity or decrease the evaporator airflow. Assuming this system has a fixed compressor capacity, high dT is a clear and unambiguous indicator of insufficient airflow... period.

[Gary]

One of the more common problems in using this type of system in a server room is over-dehumidification, which is all the more reason to increase the evaporator airflow. Assuming a room temperature of 21C/70F, in order to avoid drying out the room you need the air off temperature to be no less than 10C/50F. IOW, assuming air on temperature of 21C/70F the dT needs to be no more than 11K/20F.

[marc5180]

Ok long shot

its not cross wired is it, have you traced the pipe work from each condenser to its indoor units and belled out the wires. I have seen units run for years like this with out any one noticing untill a problem crops up as no fault codes will show for this, believe me we have taken over a contract with more than 1000 of these units on maintenance contract at the minute and still keep finding units cross wired (dodgy installers).

Assuming 1 system does one side of the room and one the other, originally one of the two systems was more than adequate to cool the room down when first installed so cross wires still made units cut in and out nicely as room always got to temp which ever condenser ran. Suddeny more IT kit is put in the server room so more demand on kit and one system will not acheive set point any more, say left hand of room gets to temp and turns its condenser off but it is actually the right hand right side of the room that looses cooling.

Try to get your head round this, this causes the units on the left to run just about continuous as the right hand side of the room gets warmer, while the left hand side is cutting in and out cooling to the right on thermostat topping up on cooling, phew as good as the explanation will get after beer and kebabs..!!

We had this happen a few weeks ago, no faults codes at all, might not be the same for you but worth checking...Good luck.

Also, cassettes in a server room, not a good idea, its not will an AC unit leak water its when. From the model code you give i see they are R22 and upto ten years old, maybe talk the customer into some new kit, waiting list on parts for these units in summer is bad, especially compressors. They must be ready to chuck a seven any time now.

We havent actually belled the wires out but the sytem that runs allthe time( the one thats working fine) the condensor is always on, so when im with the condensors and the indoor unit that faults gets turned on and off then we know which condensor it is

[marc5180]

Given the numbers supplied by coolments, there is no doubt in my mind that this system has an airflow problem. If the identical system has similar evap dT, then both systems have airflow problems.

The question then is not, "Why is this system freezing?" but rather, "Why is the other system NOT freezing?". Is there some sort of automatic defrost mode? Perhaps a low pressure or low temperature switch that shuts the compressor off and allows the coils to defrost?

There are only two ways to increase the delta-T: Increase the compressor capacity or decrease the evaporator airflow. Assuming this system has a fixed compressor capacity, high dT is a clear and unambiguous indicator of insufficient airflow... period.

Hi Gary, no i dont think there is an automatic deforst mode. When i got to the unit when it had frozen up i interrogated the controller and found the evaporator sensor reading -13Degc ( which i thought would have cut the unit off on a fault, but it didnt) but the return air was reading 24DegC so even though the coil was frozen up because it hadnt got down to temperature the unit was still calling for cooling regardless of the evap freezing up. the compressor is a fixed speed compressor and the indoor fan speed is always set on high. Both indoor coils are clean so i cant see airflow as being the problem even though it seems obvious.....

[Temprite]

Ok long shot

its not cross wired is it, have you traced the pipe work from each condenser to its indoor units and belled out the wires. I have seen units run for years like this with out any one noticing untill a problem crops up as no fault codes will show for this, believe me we have taken over a contract with more than 1000 of these units on maintenance contract at the minute and still keep finding units cross wired (dodgy installers).

I also believe this could be the cause of your problems. Have seen similar things especially on multi units.

Usually there would be some kind of freeze prevention or protection and the unit would lock out depending on make or model.

Set the controller as low as possible and if you can choose a fan only setting on one of the units.Check the air off temp on this unit if it is colder than the air on then odds are it is cross wired

[Gary]

Hi Gary, no i dont think there is an automatic deforst mode. When i got to the unit when it had frozen up i interrogated the controller and found the evaporator sensor reading -13Degc ( which i thought would have cut the unit off on a fault, but it didnt) but the return air was reading 24DegC so even though the coil was frozen up because it hadnt got down to temperature the unit was still calling for cooling regardless of the evap freezing up. the compressor is a fixed speed compressor and the indoor fan speed is always set on high. Both indoor coils are clean so i cant see airflow as being the problem even though it seems obvious.....

Both of these systems have airflow problems and both of these systems are freezing the coils. The system that is "working fine" is in fact somehow defrosting itself.

Surely there must be some way to lock the fan speed in at it's highest speed and run it continuously. These systems need all the airflow they can get, especially in a server room. If the highest speed isn't enough then perhaps bigger fans/motors are needed.

Do these systems have squirrel cage type fans? Are the blades clean? Are they running in the right direction? Is air bypassing the coil?

[Brian_UK]

May be possible with this make I'm not sure but...

Recently looked at a Mitsi cassette and was bemused with the odd airflow coming out of the unit.

At first I thought that blanking plates had been fitted but then realised that some of the internal insulation material was coming unglued.

This then allowed a flap of plastic/polysytrene to close the discharge slot with the airflow from the fan.

Might be worth another look.

[marc5180]

Both of these systems have airflow problems and both of these systems are freezing the coils. The system that is "working fine" is in fact somehow defrosting itself.

Surely there must be some way to lock the fan speed in at it's highest speed and run it continuously. These systems need all the airflow they can get, especially in a server room. If the highest speed isn't enough then perhaps bigger fans/motors are needed.

Do these systems have squirrel cage type fans? Are the blades clean? Are they running in the right direction? Is air bypassing the coil?

the fans are always on high speed, they dont have the cage type fans and im pretty certain they are running the right direction.... the blades are clean and cant see why air would be bypassing the coil

[marc5180]

May be possible with this make I'm not sure but...

Recently looked at a Mitsi cassette and was bemused with the odd airflow coming out of the unit.

At first I thought that blanking plates had been fitted but then realised that some of the internal insulation material was coming unglued.

This then allowed a flap of plastic/polysytrene to close the discharge slot with the airflow from the fan.

Might be worth another look.

Blanking plates defo have not been fitted but i havent checked the internal insulation has come loose Bryan so it something else to check on Monday morning
cheers

[lana]

24C/75F - 4C/39F = 20K/36F dT

On a conventional A/C, I would expect an evaporator dT of 14.5K/26F or less even for the high efficiency systems and considerably lower for a lower efficiency/older system.

I would say the evaporator airflow is way too low.

Gary is completely right here.

Measure the super heat. It is for sure very low. This is the classic symptom of Lack of Evaporator capacity.
If there is high DT of air (which you have) then there is air flow problem.
If DT air is low then coil is dirty and heat transfer doesn't occur very well.

Why don't you try some of the advices given in this post?

Good luck
Cheers

[marc5180]

Lack of Evaporator capacity???? How? The units has been running fine for years but now all of a sudden its started having these problems and no extra load had been put in the room i.e servers.. Il try some of the suggestions on here tomorrow and report back..

[Gary]

Lack of Evaporator capacity???? How? The units has been running fine for years but now all of a sudden its started having these problems and no extra load had been put in the room i.e servers.

I suspect the units have been freezing up and then defrosting themselves for years, thus giving the appearance of working fine. The problem unit is no longer defrosting itself.

You said yourself that the evaporator temp was very low without triggering a fault. Why would the manufacturer go to all the bother of installing an evap temp sensor if it doesn't trigger a response? What is it supposed to do?

I suspect that low evap temp is supposed to shut down the compressor, thus allowing the coils to defrost. If you monitor the other unit, you will probably see it shutting down its compressor periodically.

Both of these units have airflow problems. One of these units is no longer hiding the problem.

[Gary]

I'm thinking that a wiring diagram might be very helpful. It is entirely possible that the fan motors are wired wrong, so that a call for high speed results in medium speed. Or perhaps the fan blades are installed backwards, backhanding the air. You might want to check the fan motor amperages to see if they are running full load amps. If not, why not?

[Jase]

Possibly a low latent heat problem occurring.
As the units are in a server room the humidity can be low so when this happens if the units are in cooling the moisture will freeze on the evap coils and cause the units to operate @ lower suction pressures/temps.
Surely the sensors on the evap coils should cut the unit off!!
This situation might not be occurring with the other 2 cassettes as maybe more load @ the 'problem' side of the room.
Just a thought!

Regards
Jase

[marc5180]

Possibly a low latent heat problem occurring.
As the units are in a server room the humidity can be low so when this happens if the units are in cooling the moisture will freeze on the evap coils and cause the units to operate @ lower suction pressures/temps.
Surely the sensors on the evap coils should cut the unit off!!
This situation might not be occurring with the other 2 cassettes as maybe more load @ the 'problem' side of the room.
Just a thought!

Regards
Jase

I would have thought it would cut the units off to but when i spoke to Hitatchi and explained that the evap coil temp was -13, he asked me what the return air was and i said 23degC and he said well theres your problem. The units hasnt got down to temperature and even though the coil is sensing -13 it wont go off because the unit is still calling for cooling. He said this is how they work...BUT then if thats the case then why put a sensor on the coil???

[philjd26]

hi there,dont know much on hitachihowever just glancing through and i dont think i seen anybody ask is it a capillary tube or what,is the fan speed controller ok as it might not be maintaining the correct head pressure to satisfy the cap application thus giving you low evap temps,sounds like around 2 brg after expansion possible blockage or moisture...might wanna take a look at the head pressure.....also i would consider swapping indoor pcb card provided all sensor check out ok

[marc5180]

Been back to the unit today and found it iced up again, both evaporators and the suction line all the way to the compressor 2inch thick. When i first got to site the units were froze up so i turned them off on the controller, went upstairs and found the compressor still running. The compressor contactor was pulled in so i gave it a slight tap to see if it was jammed in and it popped out... i thought that was the problem but then i took the signal wire form the PCB off and tested if the Pcb was calling for cooling which it was... I tried to tap the contactor again but it stayed in. The outdoor fans work off pressure so they dont have a fan speed controller.

Anyway though id list the things i checked today

1) checked fan motors not running backwards, impellors clean
2) checked coils were clean
3) checked no blanking plates were fitted or anthing was blocking the evaporator airflow
4) checked fan speed, low, medium and high which was ok
5) checked for crossed wires...they werent
6) Raised the temperature to 30 degc to see if it cut the unit out...which it did then back down to 19degc and vice vesrsa a few times and it kept cutting out and starting as it should
7) Evaporator temperature was -19degC when i got there so i turned it off and returned later in the afternoon when i the ice had melted and i could check the superheat and subcooling.
Subcooloing was 8Deg but the superheat was 1deg.

As i was at the condensor later on in the afternoon when all the ice had melted the condensor went to start and i heard i funny noise in the condensor and looked underneath the fan and found the suction accumulator totally froze up.. Im now wondering if the unit is overcharged and there is a problem with the accumulator because if you remeber i recovered 7 kg where as there should have been 11.5kg but no leak was found?? What do you guys think

[marc5180]

hi there,dont know much on hitachihowever just glancing through and i dont think i seen anybody ask is it a capillary tube or what,is the fan speed controller ok as it might not be maintaining the correct head pressure to satisfy the cap application thus giving you low evap temps,sounds like around 2 brg after expansion possible blockage or moisture...might wanna take a look at the head pressure.....also i would consider swapping indoor pcb card provided all sensor check out ok

Hi Phil,The units are capillary type expansion devices and the boards have already been swapped previously by another engineer

[Jase]

It appears to be a common problem on Hitachi splits where the suction accumulators freeze up. There should be a hot gas tapping onto the accumulator which should inject hot gas depending on the operation of the unit. Are the sensors in the outdoor unit all normal?

Jase

[frank]

I've just reread this post and realised that you say the charge should be 11.5kg. For a twin split? Where does this figure come from?

i recovered 7 kg where as there should have been 11.5kg

What capacity are the indoor and outdoor units?

Still stick with my original theory - contactor welded or sticky.

went upstairs and found the compressor still running. The compressor contactor was pulled in so i gave it a slight tap to see if it was jammed in and it popped out...

[marc5180]

It appears to be a common problem on Hitachi splits where the suction accumulators freeze up. There should be a hot gas tapping onto the accumulator which should inject hot gas depending on the operation of the unit. Are the sensors in the outdoor unit all normal?

Jase

I plan to have a look at the accumulator in the morning its behind the compressor and electrics behind a plate so iv got to take the condensor apart to get to it. Havent checked any sensors on the outdoor yet....any sensors in particular??

[marc5180]

I've just reread this post and realised that you say the charge should be 11.5kg. For a twin split? Where does this figure come from?


What capacity are the indoor and outdoor units?

Still stick with my original theory - contactor welded or sticky.

Charge was on the side of the unit11.5kg, the indoor units are 5Kw each, contactor defo isnt welded but could well be sticky but even if it is... the unit was still calling for cooling when the indoor coil was at -18 so it shouldnt be asking for it should it?

[philjd26]

hi, i agree with frank on this,is the unit running 24/7 or? you said that you turned controller off when iced up and found contactor still energized by outdoor control and not dodgy contactor....could someone be turning this unit off at any time in the day? i would imagine the indoor fan stops for what ever reason! you say it a 2 to 1 system is both indoors boards ok, have you seen them satisfy on temp? super heat seems small aswell is both units get refrigerant through...and not just flooding one...let me know how you get on??

cheers