Heat Pump Frosting Over

Old 03-02-03, 09:57 AM
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Heat Pump Frosting Over

We have a seven year old Lennox model #B24Q that has had a number of problems. I will just mention the ones that I think may have an impact on the current problem. Due to a leak in a line near the inside coil, the tubing was repaired and the unit recharged. Our electric bills seemed lower so the expectation is/was that the serviceman maxed the freon. The compressor then failed to start. The fix, a new start/run capacitor and start/run relay. An OEM part, different part number and appearance but we were assured that it was equivalent. Then the inside blower motor became intermittent and finally quit. The fix, a new furnace mounted two pole circuit breaker (one leg of the old breaker failed, the leg to the motor) Then the condensor fan blade sheared off of its mounting to the motor drive shaft. This failure caused the condensor to frost, maybe one inch. We were not aware of a similar frosting problem till then. The fix was a readily available generic fan assembly (weekend, no OEM in stock). The volume of the new blade seems to exceed the old blade. (smaller blade size but a stronger pitch). The condensor is now heavily frosted maybe 3" thick. Overnight temps in the 20's, current temp about 30. Cut the circuit breaker to the heat pump, running on back up heat with blower running continually. Emergency heat light at thermostat not activated. Any help would be appreciated.
Old 03-02-03, 10:49 AM
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I would suggest you change your HVAC company, from your discription of cascading problems with your system. Freon charging during winter months is very critical, alot of servicers tend to overcharge the system. This will cause liquid freon to acumulate in the compressor during off cycles, thus causing severe hard starting and stress to compressor windings. Changing HP fan pitch and size will also cause problems with the amount of heat an HP can absorb or discharge. Sounds like you have no EM heat wiring or a problem with wiring. Defrosting problem can be from overcharge/undercharge/new fan prop.
Old 03-02-03, 01:29 PM
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i agree, get a new company out there for a full analysis of the situation.
Old 03-02-03, 07:27 PM
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problems with the heat pump

This unit is seven years old, operates 24/7, and everybody wants it to last forever. Things break! The broken tubing has nothing to do with the breaker. The fan blade is most likely exposed to ultraviolet and water which breaks down any material, and maybe with the weather we've had here ice was on the blade which broke it, if you don't like the heat pump, scream at Lennox, the mechanic has nothing to do with those break downs.... as far as the defrost goes you had better fix that Monday or you'll need a compressor. It sounds like the defrost control has died. Frost not ice, will build up heavily between 25F and 45F quite a bit, have you read these posts on this forum, lots of people can't even get someone to their house this time of year...As long as the fan doesn't overamp the motor your OK...amp draw is the measuring stick to go by...

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