Out Side Unit Freezing Up

[icemanxxxv]

Last winter my outside unit froze up like a block of Ice! The service man came out and changed a thermistor for the defrost cycle. Then returned on a warmer day to service with refrigerant. All seemed well but the system was grossly over serviced and in the spring the unit started squalling like a wounded cat. They returned and said it was popping the pressure relief valve and they serviced the refrigerant to proper level. Then there was constant buzzing coming from the unit even when it wasn't running and they were back out to shim some valve. Mind you this was all under warranty. Now the first cold snap comes and the unit is a block of ice. So they say it needs a defrost board... Which I told them it needed last winter because even after changing the thermistor it would only stay in defrost for maybe 30 sec to a minute and a half... Now supposedly the board has been changed and the unit still ices up to the louvers and never completely defrosts. I get about 5 minutes of good heat pump heat and then it blows cold. The unit hardly ever cycles off! My guess it only cycles off for the defrost cycle. Also my neighbor right next door has the same unit and his never has anything more than light frost on it. Now before I get dismissed as some know nothing homeowner I have been an A&P Mechanic for over 20 years. I Work on every system a Boeing 737 has I am astutely aware on how things are supposed to work and when something is wrong Including but not limited to A/C


Thanx Guys!!!
Steven Adler

[BaldLoonie]

What brand are we speaking thereof?

[millerman]

Probably a Rheem.

[icemanxxxv]

Sorry it's a Trane

[Wild Leg]

...and the model number is?

[icemanxxxv]

Will post tomorrow Its dark now and snowy!

[smokin68]

sounds like you need to speak with the service manager....if it was overcharged last year,they overcharged it, which throws up a flag. Now it won't heat or defrost properly. Time to send a better tech.....

[docholiday]

Much like many other times you will probably eventually find the defrost board is not to blame. Defrost is performed by refrigerant gas, the board merely switches it in and out and has its limitations and algorithems to follow. If your system is going into defrost, then the board is likely fine. The sensor may also not be firmly attached to the right spot since einstin messed with it. If the refrigerant charge is incorrect, then defrost will not work. There are no magical heaters, there is simply a requirement that the warm discharge gas does the work.