Coleman Heat Pump BRHQ0361BB won't go into defrost

[jester]

I have a Coleman BRHQ0361BB heat pump, manufactured in 1996 that is freezing up and not going into defrost mode. My heating and air guy has replaced the defrost board and sensors but it still will not go into defrost mode. The A/C works when we turn it on, so the reversing valve seems to be working.

What happens when my tech tries to get the unit to go into defrost by shorting the pins on the defrost broad is that it will try to go into defrost but it kicks right back out. You can hear a relay click but that's all that happens.

What can the problem be. My tech has thrown his hands up and is ready to call it quits.

Thanks,
John

[Robert]

Hi John,

Did he test the new board and sensor to ensure they are working ?

You also have to remove the short very quickly for it to remain in defrost, did he do that ?

What are the part numbers of the new parts ?


What is outdoor temperature at that time also ?


Thanks,
Robert

[jester]

He just took the board out of the box and installed it. The same with the sensor. Tested it..No.

Yes he removed the short quickly.

I've got a call into him for the part numbers of the new parts.

The outside temp was in the upper 30's to the low 40's.

Just a thought, could the stat have any bearing on this problem. This system has been though six or seven stats since it was installed, and the stat was malfunctioning along with the problem of not defrosting. The repairman replaced the relatively new stat that he had replace about 3 or 4 months earlier. I was just wondering if it might be miss wired or something. As you can tell, I know very little about heating and air except you turn the stat up for heat and down for cool. ;o)

Thanks for your help.

[Robert]

T-Stats are rarely the problem, so replacing that many would be ludicrous. IF the problem remained, the new parts should have been tested for proper operation.

Secondly, they should not have been replaced until it was proven they were the fault.


I would call another hvac tech that is knowledgeable in heat pumps. That one don't seem to be very proficient or skilled at his job.

A wiring miscue could be the problem, but won't know until circuit is tested.



Thanks,
Robert