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Minisplit troubleshooting

D

diseasedmind

Active member
I have a 3 zone minisplit , and one of the 3 head units is not cooling. it keeps freezing up on the outside unit connections and also the inside unit evap coils. filters cleaned, condensate lines clear, outside unit cleaned of debris, checked for kink in line set.

any suggestions on what might cause this? or how to fix?

thanks
 
S

snake11

Member
diseasedmind said:
I have a 3 zone minisplit , and one of the 3 head units is not cooling. it keeps freezing up on the outside unit connections and also the inside unit evap coils. filters cleaned, condensate lines clear, outside unit cleaned of debris, checked for kink in line set.

any suggestions on what might cause this? or how to fix?

thanks
Click to expand...

What brand and model?
 
D

diseasedmind

Active member
It is a klimaire minisplit not sure on the model. No they are not the same distance from the outdoor unit. The 2nd furthest from the outdoor unit is the problem. When that one is on it causes the idoor unit that is closest to the outside unit to completely freeze over
 
Q

queequeg152

Active member
Veteran
diseasedmind said:
It is a klimaire minisplit not sure on the model. No they are not the same distance from the outdoor unit. The 2nd furthest from the outdoor unit is the problem. When that one is on it causes the idoor unit that is closest to the outside unit to completely freeze over
Click to expand...

it sounds like your eev(electronic expansion valve) might be faulty?
idk im not a pro, i just play one on tv.

these valves meter refrigerant to the exap. coils...

check the sensor on your evap coil, and check the sensor on the condensor coil.

you might also check your branch box if you have one... i doubt you would have a branch box for a small 3 zone system.

replacing these things will be a bitch... hope im wrong about this.

could also be a bad blower... though a smart VRF system with variable speed blowers should alert you to this? they usually have rpm sensors... a bad blower should throw an error code.

could also be an impropper charge of refrigerant, or a refrigerant leak. i dont suppose you have a sight glass?

could also be moisture in the system. i dont suppose you have a moisture indicator installed? ( almost nobody does)
 
S

snake11

Member
queequeg152 said:
it sounds like your eev(electronic expansion valve) might be faulty?
idk im not a pro, i just play one on tv.

these valves meter refrigerant to the exap. coils...

check the sensor on your evap coil, and check the sensor on the condensor coil.

you might also check your branch box if you have one... i doubt you would have a branch box for a small 3 zone system.

replacing these things will be a bitch... hope im wrong about this.

could also be a bad blower... though a smart VRF system with variable speed blowers should alert you to this? they usually have rpm sensors... a bad blower should throw an error code.

could also be an impropper charge of refrigerant, or a refrigerant leak. i dont suppose you have a sight glass?

could also be moisture in the system. i dont suppose you have a moisture indicator installed? ( almost nobody does)
Click to expand...

Agree. I would be looking towards the EEV or a blockage in the line.
 
Heusinomics

Heusinomics

Active member
Check online to see if there are error code lights on the outdoor unit...
You will hav to remove the access cover.
My LG mini has a series of colored lights that blink to indicate if a prob has been detected by the unit.
The codes are not in the installation guide so you wd have to look them up on the net

Best o luck to you
 
Tangwena

Tangwena

Well-known member
Veteran
Does the furthest unit effect the others when it is on? The reason I ask is it sounds like the first (closest) unit is being starved of refrigerant. If you have the furthest away unit on and any one of the other two on what happens? Try all combinations of units on ie first only, first and second, second only ect.
It will indicate if refrigerant charge is low, if it is you have a leak, check all connections with a thick mixture of soap and water any leak will blow a bubble.
Tangwena
 
D

diseasedmind

Active member
is it one charge for the entire unit or does each zone have its own charge? I will try to switch up the zones starting with the furthest on first.
 
Tangwena

Tangwena

Well-known member
Veteran
Hi Buddy I dont know if its a vrf unit or not if it is it has one compressor and as the demand increases releases more refrigerant, therefor if the unit furthest from the compressor is on it follows less refrigerant is available for the remaining units.
As some refrigerant is lost in the pipes going to and from the unit that is operating. When installed new it will have either had enough in it (usually the manufacturer will give a maximum pipe run length in the instructions),or the installer would have calculated the extra required and added it to the system using the formula in the installation instructions.
So using this we can assume that with the furthest running,that one of the other 2 will cause the charge to be low if it is used.
For instance the closest might run ok as it needs less gas being closer, or a combination of other units may be ok but when you use the 3rd unit as well as the other the charge will be to low and iceing occurs in the unit being starved.
If this occurs you will need to get a frigee to fix it and recgarge the correct weight of refrigerant back in. I hope this helps.
Tangwena
 
S

snake11

Member
diseasedmind said:
is it one charge for the entire unit or does each zone have its own charge? I will try to switch up the zones starting with the furthest on first.
Click to expand...

There is one charge that is shared with all of the indoor heads/evaporative coils and outdoor compressor/condensing coil.
 
D

diseasedmind

Active member
ok I am getting no freeze up when running the closest and furthest on lowest temp setting. does this rule out low charge/Leak? what should I try next?
 
D

diseasedmind

Active member
I put the middle zone on Heat mode and it seems to be running fine, could it still be the expansion valve? is there one for heating and one for cooling?
 
Tangwena

Tangwena

Well-known member
Veteran
The problem could be a malfunctioning expansion valve, if it is there is nothing you can do about it, you need to call a fridge technician. May I ask was the middle unit operating on its own when you tried it? if so it could still be the gas charge try all 3 on heating at once to check, if they all work ok then its not the gas. Also who installed the unit?
Tangwena
 
r2k

r2k

Member
I can only share my experience.

I have a three ton outdoor compressor. After several years, we found the outdoor compressor was freezing up. It was covered with ice.

At other times, I have found the indoor evaporator coil was so cold that it turned into a 15 pound block of ice and no cooling occurred.

Both times, it turned out the same problem with different conditions. Low refrigerant. the freon had leaked out slowly (or maybe it was never filled in the first place when installed) and this changes the operating point. It seemed counter-intuitive to me, but low refrigerant causes the coils to become colder, not warmer. When they get colder than 32*F, ice forms from humidity in the air.

The solution is simple. You must immediately turn off the unit and let it defrost. Don't try to break off chunks of ice, you will almost surely damage the coils or fins. Just let it melt. Meanwhile, find a nice A/C technician that does jobs on the side at night. Make sure you get the correct refrigerant number for your unit. The technician will have pressure valves to measure the various pressures at the test points. If your unit has them, of course.

New freon is inserted on the low side pressure input. It is sold by the pound and they weigh the tank with a digital scale before and after to know how much weight was put in.

I am assuming that your freezing head has a complete freon circuit independent of the other circuits. I suspect your unit has one compressor and three evaporator coils. As others pointed out, there must be some kind of valve that regulates how much liquid freon goes into each leg. Regardless, this isn't something you can fix on your own.

Is the freezing leg on a different length of hose? A longer tube will have more pressure loss and restrict the flow of freon, so I would guess that it might cause your problem.

Can you connect the hoses to different indoor units? It would be interesting to see if the problem follows the indoor unit or the hose it connects to.

There is a Klimair installation manual at this link: http://www.heatandcool.com/v/KLIMAIRE PRODUCTS/KSWT/OWNERMAN.pdf

There is a Klimair service manual at this link: http://www.thermospace.com/klimaire/KSIN-Service-Manual.pdf

There is an installation manual link for Klimair at this link: http://www.thermospace.com/klimaire/spec-sheets/MULTISERVMAN.pdf Figure 3.2 looks like the closest to what you describe. There are valves for each circuit labeled 'EXV'. The manual hints that you can see something on the valve that moves when it opens and closes. Can you find that? If so, does the faulty circuit valve open as much as the other two?

It would really help if we knew the exact model number, age, etc of your unit. Google works best if you type in the model number and add terms like "service manual". The links above are only what I could find with the limited information you have provided. I don't know if they are applicable to your hardware or not.

-r2k
 
S

snake11

Member
r2k said:
I can only share my experience.

I have a three ton outdoor compressor. After several years, we found the outdoor compressor was freezing up. It was covered with ice.

At other times, I have found the indoor evaporator coil was so cold that it turned into a 15 pound block of ice and no cooling occurred.

Both times, it turned out the same problem with different conditions. Low refrigerant. the freon had leaked out slowly (or maybe it was never filled in the first place when installed) and this changes the operating point. It seemed counter-intuitive to me, but low refrigerant causes the coils to become colder, not warmer. When they get colder than 32*F, ice forms from humidity in the air.

The solution is simple. You must immediately turn off the unit and let it defrost. Don't try to break off chunks of ice, you will almost surely damage the coils or fins. Just let it melt. Meanwhile, find a nice A/C technician that does jobs on the side at night. Make sure you get the correct refrigerant number for your unit. The technician will have pressure valves to measure the various pressures at the test points. If your unit has them, of course.

New freon is inserted on the low side pressure input. It is sold by the pound and they weigh the tank with a digital scale before and after to know how much weight was put in.

I am assuming that your freezing head has a complete freon circuit independent of the other circuits. I suspect your unit has one compressor and three evaporator coils. As others pointed out, there must be some kind of valve that regulates how much liquid freon goes into each leg. Regardless, this isn't something you can fix on your own.

Is the freezing leg on a different length of hose? A longer tube will have more pressure loss and restrict the flow of freon, so I would guess that it might cause your problem.

Can you connect the hoses to different indoor units? It would be interesting to see if the problem follows the indoor unit or the hose it connects to.

There is a Klimair installation manual at this link: http://www.heatandcool.com/v/KLIMAIRE PRODUCTS/KSWT/OWNERMAN.pdf

There is a Klimair service manual at this link: http://www.thermospace.com/klimaire/KSIN-Service-Manual.pdf

There is an installation manual link for Klimair at this link: http://www.thermospace.com/klimaire/spec-sheets/MULTISERVMAN.pdf Figure 3.2 looks like the closest to what you describe. There are valves for each circuit labeled 'EXV'. The manual hints that you can see something on the valve that moves when it opens and closes. Can you find that? If so, does the faulty circuit valve open as much as the other two?

It would really help if we knew the exact model number, age, etc of your unit. Google works best if you type in the model number and add terms like "service manual". The links above are only what I could find with the limited information you have provided. I don't know if they are applicable to your hardware or not.

-r2k
Click to expand...

If there is a leak it must be fixed before recharging. Otherwise you will be in the same position a while later. Better to do things right the first time.
 
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