Frequency of defrost cycle on Bryant heat pump

9 years ago

I have a 3 year new 2800 sq ft home in northern ohio, over insulated, top of the line windows heated by Bryant hybrid heat pump/ propane fired furnace. i believe it is 100K BTU & 5 ton AC. I've never been confident in the installer. have paid for 2 service calls to check system thoroughly and was told everything was correct. I have 2 concerns. at times (not during extreme coldness) the heat pump seems to operate way too long to satisfy the stat which is set to 65 24/7. sometimes this is in excess of 1 hour. this fall/ winter we've been burning wood only up until 2 weeks ago. having had surgery, we now have the heat pump on. the defrost cycle seems to be operating way too often. the last couple of nights I've not slept well and counted it defrosting 6 or 7 times. low temps have been upper 20's and low 30's. is this normal? if not normal, what is typical? If not, what could be causing this? i also found out this AM the furnace was firing with it being 38 degrees out (but set to come on at 20 degrees). I have a call into a different heating company to schedule another system check if your responses indicates I need one. thank you in advance for your professional opinion.

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Comments (3)

tigerdunes
9 years ago
What Mdl Bryant HP?

Bryant utilizes a time/temp defrost feature which can be set to 30/60/90 minutes regardless whether it is needed or not. The Evolution Mdl heat pump is a bit more advanced working off a software algorithm. Not much better though.

Any idea what your defrost setting is?

When going into defrost, have you checked to see if the defrost cycle is even required?

It might be helpful if you provide complete Mdl numbers of both HP and furnace. What thermostat Mdl do you have?

Certainly the number of defrost cycles you describe could be correct. But it also seems something is wrong with your lockouts. If you are not familiar with your thermostat/controller settings, it is probably best to have a pro take a look. I think I would want the HP set at 60 or 90 minutes for your defrost calls. You are aware your backup propane fueled furnace will be used to temper the air on each defrost call. That can be expensive.

IMO
sunroomguy
Original Author
9 years ago
I neglected to mention it is the plus 95s evolution system with evolution stat. I do not know the defrost setting. The model # shown on what I believe is the furnace manual is 355CAV. There is also a model # CNPVP6024ACAABAA on a tag on the outside of the furnace, and a model # 355CAV0600100 on a tag inside the front cover. The heat pump model # is 265ANH060-B. the next closest Bryant dealer is an hour away. I have a heating guy I've used for years but not sure if he's knowledgeable with Bryant (waiting on his return call). I did not know the furnace fired as part of the defrost cycle. the dealer nor installer provided no instruction on this system. I'm surprised with todays technology that the defrost will function whether needed or not. also, the outside temp on the stat is often off as much as 20 degrees. is this to be expected? thanx for taking the time to respond.
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Hi. Thanks for replay. The outdoor fan is fine and spins on its own with out any assistance when jump wired across the 1-2 terminal on the defrost relay which is for unknown reason energized in cooling mode. It should be off in cooling mode where those contact are closed in normal position for the fan to come on. I measured 24 volts on the coil of the defrost relay which is mystery while I am in cooling mode. That 24 voltage should be present only in defrost mode for faster deicing when the outdoor fan is cutoff of power. I removed the wire to the defrost relay so the outdoor fan can run and I disabled the heat switch on the thermostat for the rest of the winter. The unit works fine with the defrost relay disabled. Once I connect the defrost relay back the outdoor fan can't get the juice due to the opened contacts on the defrost relay. As I mentioned it's energized by the defrost board in cooling mode and that is strange for new board unless some external element like thermistor would activate it but it shouldn't be in cooling mode I guess. Now the issue is about the heating for the next winter. I have all 220/24 voltages correct. It was working fine for one week including the heating but I am going to give them call again just to make sure. The unit was working in both heat and cooling when I was leaving, I doublechecked that before I left since it takes me 45 minutes to get there with my 5.8L engine these days. We don't use the outside air to cool inside and they called me back that the cooling doesn't work and there I discovered the mystery. The unit is made in 1978. The unit comes on when thermostat calls for cooling but the outdoor fan is disabled by the energized defrost relay. Thanks again.
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I too am having the same problem and very similar to Sparky. I too have a Goodman unit that was installed about 4 years ago and the outdoor unit replaced again after a year and it failed. I too have just noticed cold air blowing out and apparently it is during the defrost cycle. I put a hout thermometer on it and it will normally run around 84 degrees at the register but at times will run about 68 degrees. The temp outside has benn mid 20s to mid 30s. The furnace guy came out and said the filter was plugged and had kicked out the heat strips. I questioned this, but figured he knew what he was doing. After he left if continued to happen and had him out again. He 'added' a board to turn the unit off during defrost. Doesnt sound like that can be done from what I read. In any case he left and the unit continues to do the same thing. It sounds to me that the heat strip must not be coming on during defrost. What part that might be is probably the question. Does anyone know if the heatstrips have an interanl 'breaker' or theraml cuttoff. I know I checked the breakers back at the panel and the breakers on the indoor unit and they were normal before the heater guy showed up and told me he had to reset these. Any thoughts or possible solutions from the others that are experiencing the problems please let me know.
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tigerdunes
9 years ago
No, you have issues that can only be addressed by either an authorized Bryant or Carrier dealer. You specifically should have an owner's operating manual for the Evolution controller, your fault for not having one. Plus verify the time setting for defrost call. Something you should know how to set yourself.

IMO

Frequency of defrost cycle on Bryant heat pump

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tigerdunes

sunroomguy
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Frequency of defrost cycle on Bryant heat pump

Comments (3)

tigerdunes

sunroomguyOriginal Author

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sunroomguy
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