More Heat Pump Questions

On 5/23 I started a thread with the subject "Heat Pump Performance Questions". There were several helpful responses, but now I have a few new questions. For several days our 6 year old Carrier HP system seemed to be somewhat unpredictable and out of control. Many times the air handler would start without the compressor running. Sometimes the compressor would start 5 or 10 minutes later. At other times both would start together, but after 5 or 10 minutes the compressor would shut down while the air handler continued to run. On one occasion I was working in the yard near the compressor and heard it start up. I walked over to it and felt the exhaust air to see if it was warm -- and it was. Then after 5 or 10 minutes of running, the compressor FAN stopped, while the compressor itself kept running for another minute or two before stopping. (Is this a big clue? -- should the compressor fan EVER stop while the compressor continues to run?) During these times the indoor temperature sometimes rose to 2 or 3 degrees above the set point. And now, as if to add to the mystery -- the system suddenly began to act completely normal 3 days ago and through today, with none of the strange behavior listed above. At a routine service call one month ago (and before some of the above symptoms appeared) the dealer's serviceman reported the system to be in good shape and performing normally. Can anyone please offer some explanations or comments? Thanks. Art Replace deadspam with yahoo to reply.
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6 years old I would guess your sequence should be similar to--- Tstat calls for cooling, compressor and compressor fan start. Interior air handler starts soon after. If your tstat has delays in it like mine you could get some pauses. In no case should the compressor be running with out the compressor fan. Time to call a pro and have it checked out. Might be something simple. I will cross my fingers for ya. My luck it...... well you know. Humor applied.
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Art Renkes wrote:

Could be compressor is locked out because of a time delay thermostat. We went through this before in great detail.

YES, BIG CLUE. Could be bad run capacitor, binding motor bearings, bad fan motor.

You'd expect that.

You're on borrowed time. It will quit working again, most likely on a day when it is over 90 degrees and the technicians have a two-week backlog. Time to locate a qualified professional.
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Hello, For whatever reason your cond fan is cutting out. Its a common problem with few sources for fault. This problem puts added stress on your compressor and you need to have this fixed ASAP.
About the compressor not always starting right away or shutting down, etc. For now you can assume its related to your cond fan motor being bad. Your compressor and or system has safety's/overloads that seem to be working. Whatever the case get the fan fixed and go from there.
About it running ok now. Has it been cooler or raining the last few days? I'm sure you get its still broken.
When the tech replaces the needed part(s) ask them to clean the cond coil and re-check the system for proper charge.
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On Wed, 2 Jun 2004 23:44:29 -0400, "GETCOOL-MARK"

Thanks to all of you for the comments and advice. Do you suggest that I have the dealer's tech check it out now (after 4 days of normal performance)? Is it likely the tech would be able to diagnose a faulty compressor fan at a time when it is behaving normally? I know that waiting until it quits completely is not a perfect solution either, but I'm unsure of the best approach -- (maybe discussing it with a service manager if I can get one on the phone?). Anyway, I do thank you all for your time and help. Replace deadspam with yahoo to reply.
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Art Renkes wrote:

Talking to the service manager would be a good way to approach this. If the existing fan motor is over about five years old you might just ask them to replace it and the run capacitor. Should cost about $200 MOL.
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Hello, I think you on the right course here. Tell the service manager about the motor cutting out.
He will work out a simple stratagy to resolve the issue. Its not such a big deal or unique.
Lets us know how it turns out.
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wrote:

Follow-up info and questions:
1) System has been working perfectly for 6 days now (since 5/31). I just remembered that on 5/31 I temporarily interrupted the connections between the Tstat and the rest of the system by swinging the Tstat on its' hinge away from the mounting plate for observation. Could it possibly have been faulty contact between one of the pins and the mating socket, where the friction of breaking and remaking this pin to socket contact resulted in a better connection? Could this possibly explain the observed compressor fan shutdown while the compressor continued to run?
2) Carrier documentation refers to (a) a Five-minute Compressor Timeguard (to prevent compressor from starting unless it has been off for at least 5 minutes), (b) a Fifteen-minute Cycle Timer (to prevent the start of a heating or cooling cycle until at least 15 minutes after the last start of the same cycle), and (c) a Two minute minimum On Time. Are these timers an inherant part of the Tstat -- or are they effected through circuitry on a "control" board in the unit? If the Tstat itself includes these timers, then is a Honeywell replacement Tstat likely to be available with similar or identical protections?
3) Does Honeywell offer a digital NON-programmable Tstat designed for heat pumps with 2 stage heating and 1 stage cooling?
TIA Replace deadspam with yahoo to reply.
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Art Renkes wrote:

Nope. It could be a bad run capacitor, binding motor bearings, or a bad fan motor. Your symptoms will resurface sooner or later, most likely at a time inconvenient to you and the service tech that will have to work on it.

The timing functions are in the thermostat. AFAIK all Honeywell digital thermostats have a compressor lockout timer, but not the cycle timer or minimum on-time timer.

Not that I know of. Almost all of their digital models are programmable, and the ones that are not are designed for single stage (1-heat, 1-cool) applications.
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Nope...but a bad defrost board will...since it controls the fan.

All are similar, unless its a mercury switch type.

Yes. Several. The base unit we use is a non programmable, 1C 2H unit. It also has the built in time delays, and you have to remember something....all the stat controls is a 24VAC low voltage control circuit.

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3) Does Honeywell offer a digital NON-programmable Tstat designed for

Art, why do you want "NON-programmable " since you can set every period at the same setting? I have the Honeywell programmable for heat pump over 16 years, it is a great investment ~$250 installed (it should be cheaper now). I also can put it "on hold" at certain temperature so it works just like "NON-programmable".
Hai

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