Looking for thoughts:
I'm a service tech and have a new Tempstar 14 SEER HP freezing up after @ 3 hrs. operation. New TXV installed.
Return DB: 71
Suction pressure: 55
Liquid pressure: 160
Temp drop: 20
Suction line temp: 40
Liquid line temp: 80
Also, unit would no pump refigerant ( R-22 ) back into unit with suction line closed when I installed TXV. Originally had #65 restrictor.
Can't figure why unit freezes up in cooling mode, except compressor is weak or there's some bypass somewhere.
Any help would be appreciated. Thanks.
Weak compressor valves are usually indicated by suction and discharge pressure beginning to approach one another...IOW the suction will rise to a higher than normal range and the discharge pressure will drop to a lower than normal range. At 55/160 I don't see that as weak valves or compression at all. As for why you couldn't get the system to pump down, perhaps service valves at condenser leaking by? If the installer overheated both of them with his torch, that could be your problem.
As for the freeze-up, it's possible the check valve in the condenser that bypasses the outdoor TXV or piston is partially restricted or hanging up, causing the liquid line to lack adequate liquid return, which in turn starves the indoor TXV and evap coil. I'd also check your new TXV for any trash in the inlet screen, if it has one.
Main thing before you heed any of my other suggestions is to CHECK YOUR AIRFLOW!!!
Being this is a heat pump, did you install a bi-flow liquid line drier? Or a mono-flow with the arrow facing the wrong direction?
Building Physics Rule #1: Hot flows to cold.
Building Physics Rule #2: Higher air pressure moves toward lower air pressure
Building Physics Rule #3: Higher moisture concentration moves toward lower moisture concentration.
were you in heat mode when you closed the suction valve?
was the reversing valve energized or de-energized?
Thanks for the help. Sorry, forgot to mention airflow is fine as is drier. Checked the obvious first. Thanks again, gives me something to work with.
You should close the liquid line valve to pump it down.
160 head sounds low even for a 14 seer.
Are you you have good air flow.
Did you check your air flow.
Might just be alittle under charged.
Doesn't sound like a compressor problem.
Suction press low @ 55# with low 40*f suction line temp....
You have airflow problem - period.
Hope this helps,
If the airflow is fine, how would you try to explain a flooded coil with low suction pressure? You could try to say the airflow is OK but the coil has been dipped in some insulating paint and heat transfer cant take place but I think unless you are sure thats the case, you better know your airflow. To be fair, if the system airflow is good (within 10% of nominal), you better look for air bypassing the coil.
Do you have the right coil match?
What is the actual airflow?
Is there air bypassing the coil?