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alexpio
2 Posts |
 Posted - 03/02/2010 : 3:16:14 PM
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Hello,
my house is equipped with a Lennox heat pump. The condensing unit is a model # HP29-030-1P, and the inside unit is a model # CB29M-31-1P.
Everthing was fine until last week, when the low voltage transformer switch started to trip every now and then. Sometimes the pump ran for hours with no switch tripping, other times it was tripping every 2 minutes.
I called a HVAC tech, and he had to come back 3 times before he could see the pump not running. When the technician inspected the inside unit, he disconnected every single wire on the contactor strip, one by one, and every time he disconnected a wire, he then tried to start the unit, but each single time the low voltage protection on the transformer tripped, until he disconnected the tiny red wire that goes on the "R". This is the last wire on the right on the contactor strip. This is how the strip looks,from left to right:
C G W1 W2 W3 R
When he disconnected this tiny red wire and tried to start the unit, it immediately started, and run until it reached the temperature set on the thermostat. The tech then left doing nothing else, but after 2 days I noticed that the condensing unit is a block of ice. The technician does not answer my calls, and I do not know what to do.
Any idea of what is wrong with this unit? Thanks in advance for any help.
Alex
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slctech
1097 Posts |
Posted - 03/02/2010 : 6:02:50 PM
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When he was disconnecting the R wire at the air-handler's terminals, was this the R wire between the thermostat and the air-handler or the heat pump and the air-handler?
Your heat-pump is not going into defrost or the demand defrost board or sensors in the heat-pump are at fault.
I am shooting off of the hip here, but there is probability that the demand defrost board in the heat-pump was having issues and was shorting out the low voltage wiring, causing the transformer's resettable fuse to blow.
What did the technician state was the cause of the short?
How did he fix this?
Did he just leave the "R" wire disconnected?
Is the defrost board in the heat-pump blinking any applicable fault codes?
As a Lennox Technician I feel basic repairs and maintenance can be performed by the homeowner. But I highly suggest that periodic maintenance should be made by a certified licensed technician. You should contact your local Lennox technician for any repairs or issues that are outside your comfort zone. Property damage, personal injury, and death can occur from improperly repaired or maintained systems. Replacing a part doesn't always resolve the issue that caused the part to fail! |
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alexpio
2 Posts |
Posted - 03/03/2010 : 08:17:01 AM
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Hi slctech,
thanks for your reply.The technician just said that there was a short somewhere in the low voltage line, not mentioning specifically if the problem was in the heat pump or somewhere else. He just left the red thin wire disconnected and told me to call him if anything was wrong.
He checked the defrost board in the heat pump before leaving, and it was not blinking any faulty code. I'll try to get rid of the block of ice and check the for a blinking faulty code again.
If I set the thermostat to AC, would that help me to melt the ice on the heat pump?
What is your take on this issue? Since the tech doesn't reply to my calls, there's anything I can check, going by exclusion, starting from the most probable cause?
thanks again,
Alex |
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slctech
1097 Posts |
Posted - 03/03/2010 : 1:53:31 PM
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My take on the issue? I haven't a definite clue. I would suspect that the red wire he disconnected must have a purpose, not positive what it may be. I do not believe that your heatpump would be running at all without 24v constant power to the board.
My best advice is to contact another company and have fresh eyeballs take a look at it. It is obvious that the initial cause of the shorting has not been resolved, and most likely the technician exacerbated the original issue.
As a Lennox Technician I feel basic repairs and maintenance can be performed by the homeowner. But I highly suggest that periodic maintenance should be made by a certified licensed technician. You should contact your local Lennox technician for any repairs or issues that are outside your comfort zone. Property damage, personal injury, and death can occur from improperly repaired or maintained systems. Replacing a part doesn't always resolve the issue that caused the part to fail! |
Edited by - slctech on 03/03/2010 1:53:57 PM |
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