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Unhealthy CYCLE TIME (Heat Pump)

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danielc0307

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Discussion starter · #1 ·
We just bought a new home with a heat pump. I've just timed my unit and its quite alarming to me... 7:45 run time, then idle for 6:45. I'm thinking this is due to the fact that I can't set the span on my thermostat. The house just passed a new home inspection and they did check the heat/cooling cycles... I didn't ask at the time about the cycle times though. I might give them a call back because one of the inspectors was a HVAC specialist. FYI, here's some specs on the outdoor unit:
RHEEM AIR CONDITIONER
Mod.# RPMD-042JAZ
Compressor R.L.A. 18.6/18.6

Our home is 2100 sq ft ranch with a basement. Plenty of attic vents (7). Not sure what type of insulation was used in the attic but it was built 2 yrs ago so it should be decent/intact. Any thoughts???
 
#2 ·
danielc0307 said:
We just bought a new home with a heat pump. I've just timed my unit and its quite alarming to me... 7:45 run time, then idle for 6:45.

I might give them a call back because one of the inspectors was a HVAC specialist. FYI, here's some specs on the outdoor unit:
RHEEM AIR CONDITIONER
Mod.# RPMD-042JAZ
Compressor R.L.A. 18.6/18.6

Our home is 2100 sq ft ranch with a basement. Plenty of attic vents (7). Not sure what type of insulation was used in the attic but it was built 2 yrs ago so it should be decent/intact.
Click to expand...
Nearly 8 hours ON then 7 hours OFF seems approptiate
in a southern climate for a slightly undersized unit.

Run time:~ 11 AM - 7 PM
Idle time: 7 PM to 2 AM

Is the air flow up to spec?
 
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#3 ·
The most important thing.. is it keeping up with the temp you set it at? If so, or very close I'd leave it, especially if it was during a hot spell.

Now, if it can't keep up, or those are minutes not hours.... then you have a problem.
 
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#4 ·
the only thing a home inspector checks is the temp split, is the unit sized right? without a load calc you have no clue. is the airflow correct? without an airflow, balance, you have no clue. call a professional.
 
Discussion starter · #7 ·
more info..

Thermostat (and entire system) is only a year old. Digital-and yes, the system is keeping the temp exactly as set. Very comfortable-its just on and off all the time!
 
#10 ·
compressor will probably "die" quickly -- 4 starts/h is normal -- less is bad
but, check with mfgr

but, as stated, get someone to check the system -- it may be just the t-stat setup -- a service call now will be cheaper than after the compressor quits!
 
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#13 ·
Try taping a cardboard box over the thermostat. Cold air might be hitting it and turning it off early. If that's the case, you can buy a special thermostat box for that purpose.
 
#14 ·
star882 said:
Try taping a cardboard box over the thermostat. Cold air might be hitting it and turning it off early. If that's the case, you can buy a special thermostat box for that purpose.
Click to expand...
??? That's a new one to me. if you put a box over the t-stat, you are not getting a true room temp.

You'd either move the t-stat or vent.
 
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