Can you display the outdoor air temperature on the screen?
I also have a TSTATCCPRH01-B, with basiclly the same problem as the first question. After about 15 min the furnace comes on no matter what the outdoor temp(55). Option 8 = 35 and option 11= 25.
My unit is a Carrier 48XZ, can anyone tell me the basic settings for the thermidistat, dip switches, etc.
I think this was the first my dealer had installed.
Thanks for any info.
AWD
Can you display the outdoor air temperature on the screen?
Perhaps you should have read the instructions before calling.
The installation instruction book for my Carrier 38YXA heat pump describes the thermostat which (along with the timer) initiates a defrost cycle.
This thermostat closes its contacts to enable a defrost cycle at 30*F +/- 3* and opens its contacts at 80*F +/- 5*.
This means that if the temp. in the condenser coils drops to 30*F for a very short period of time and there is no evidence whatsoever of frost on the condenser, the defrost timer will initiate a defrost cycle if the temperature in the condenser coils has not climbed to 80*F to reset the defrost thermostat.
For jrbenny,
Carrier 48XZ duel fuel with TSTATCCPRH01-B
Option 8 = 35 and option 11= 25.
Yes,it has outdoor temp & rel hum.
Example this morning the od temp was 55 indoor 72, When it cooled down (indoor still read 72) to turn HP on it ran for 15 min, HP turned off fan continued to run and aux-furnance came on for about 3/4 min and then everything was off until next cycle.
Thanks
Displayed ODT = 55 when that scenario occurred? If so, you need to contact your dealer. It definitely shouldn't be firing the gas furnace unless it was in a defrost cycle. I doubt you were getting a defrost at 55.
Perhaps you should have read the instructions before calling.
I have a dual system with oil backup. The oil furnace comes on even when the temperature is above the shutout point. I am told that this happens when the heat-pump goes into defrost mode. I would think that it should go back to the heatpump after the defrost cycle but it does not. I presume this is a design error. My thermostat is TSTATCCPDF01. Is there a newer thermostat that does not have this problem?
Also it was suggested that heatpumps work best at a constant temperature. Why? There would seem to be an obvious gain from using a setback if the oil furnace does not come on except for a brief defrost cycle. Right now I am using a setback to 60 degrees at 11pm, coming up to 65 at 4am and 70 at 7am. This seems to alleviate the problem with the temperature going down to 35 but it is obviously a half-ass solution. Any thoughts?
Not a design error. We want the furnace to run for more than 10 minutes. It will help ensure a longer heat exchanger life. If we stopped the furnace with the defrost termination, the furnace may only run for 2 to 5 minutes. That's not good for your furnace. Thus, we finish the call for heat with the furnace.Originally posted by elliot cramer
I have a dual system with oil backup. The oil furnace comes on even when the temperature is above the shutout point. I am told that this happens when the heat-pump goes into defrost mode. I would think that it should go back to the heatpump after the defrost cycle but it does not. I presume this is a design error. My thermostat is TSTATCCPDF01. Is there a newer thermostat that does not have this problem?
As long as you are above your furnace lockout temp, a deep setback is fine. The problem is when you are below the furnace lockout temperature. The thermostat will want to bring on the aux heat instead of running the heat pump to recover the temperature. There goes your money savings.Also it was suggested that heatpumps work best at a constant temperature. Why? There would seem to be an obvious gain from using a setback if the oil furnace does not come on except for a brief defrost cycle. Right now I am using a setback to 60 degrees at 11pm, coming up to 65 at 4am and 70 at 7am. This seems to alleviate the problem with the temperature going down to 35 but it is obviously a half-ass solution. Any thoughts?
Perhaps you should have read the instructions before calling.
quote jrbenny
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Not a design error. We want the furnace to run for more than 10 minutes. It will help ensure a longer heat exchanger life. If we stopped the furnace with the defrost termination, the furnace may only run for 2 to 5 minutes. That's not good for your furnace. Thus, we finish the call for heat with the furnace.
----------------
I see now that someone else had the same defrost cycle problem. the problem is that with a deep setback, the oil furnace will come on and STAY ON after the defrost cycle is over even if aux heat is locked out. this may take a long time if the outside temperature is low. I presume that the defrost does not require Aux Heat to work. I don't have option 10 as mentioned above.
When I originally called my dealer, he put in a new thermostat and I only learned about defrost from a regional service manager. It seems to me that there should be a timer so that the furnace will run 10 minutes after the defrost cycle ends or I should have the option to just not have heat during the brief defrost cycle. Is it possible to rewire to achieve this or is there really no solution?
Upgrade to a Thermidistat. Dealer can program Thermidistat to not energize aux heat during a defrost.
Perhaps you should have read the instructions before calling.
You new members do realise that a defrost is the condenser running in AC mode? With no auxiliary heat on the air will be very cold.....
Sorry to bother yall......
Life goes on long after the thrill of living is gone.
And the defrost control board will run the furnace during the defrost cycle. The stat just won't be running the furnace after the call for heat. Not a fan of it, but it can be done.
Perhaps you should have read the instructions before calling.
sline-dawg said:
I should stay out of this........
You new members do realise that a defrost is the condenser
running in AC mode? With no auxiliary heat on the air will be very cold.....
Sorry to bother yall......
--
no bother; some of us are pretty ignorant and I had no idea how it defrosted. I thought it might have a heating coil for that purpose. I appreciate the education.
jrbenny said:
And the defrost control board will run the furnace during the defrost cycle. The stat just won't be running the furnace after the call for heat. Not a fan of it, but it can be done.
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To summarize (I think) --
With the TSTATCCPRH01-B thermostat-humidistat, one can force the furnace to be off during the defrost cycle which lasts about three minutes. During this time the defrost board will call for heat but the thermostat will not turn on the fan or furnace.
Thus one will simply be without heat for a few minutes. Then the heat pump will come on again and (slowly) bring the house up to normal temperature. To allow for the fact that the heatpump will heat slowly when the temperature is low one may set the on time an hour ahead or so. YES???
Now why couldn't one do this with the plain thermostat? because no one thought of it???
1 - During a call for heat with a heat pump, the indoor fan is energized.
2 - When defrost is activated by the heat pump control board, the aux heat is energized via the defrost control board. Sure, the aux heat output can be disconnected.
3 - However, in hybrid heat, the defrost is sensed by the thermostat via the reversing valve circuit. You can't disconnect this circuit as it's needed for cooling.
4 - The thermostat energizes and maintains the furnace energized through the defrost and until the call for heat ends.
5 - You can not stop the gas/oil furnace from running with a Hybrid Heat thermostat besides the Thermidistat. Control logic costs $$$. Thus, the logic isn't in the HH thermostats.
You have 3 choices - live with the furnace finishing a call for heat after a defrost, pay someone to connect a set of relays to defeat the HH stat control, or buy a Thermidistat.
Perhaps you should have read the instructions before calling.
to jr
but this is correct?
With the TSTATCCPRH01-B thermostat-humidistat, one can force the furnace to be off during the defrost cycle which lasts about three minutes. During this time the defrost board will call for heat but the thermostat will not turn on the fan or furnace.
Thus one will simply be without heat for a few minutes. Then the heat pump will come on again and (slowly) bring the house up to normal temperature. To allow for the fact that the heatpump will heat slowly when the temperature is low one may set the on time an hour ahead or so. YES???
Do you like to hear your wife complain?
Perhaps you should have read the instructions before calling.
Elliot, that is how mine works. With the thermidistat, in default settings for dual-fuel, the fan and the furnace are OFF during defrost but the compressor is running in AC mode. The whole area around the coil inside gets mighty cool, but as soon as the defrost cycle is done the fan runs and it warms up again fairly quickly. I do agree that during the first few minutes after the defrost cycle the air coming out is a bit cool, and that is why I changed the setting on mine to run the furnace while the heat pump defrosts. (increased WAF, as jrbenny pointed out) I have not noticed that the furnace continues to run until the call for heat is satisfied after the defrost cycle. I was under the impression that it shut off after the defrost cycle, but was governed by the same minumum cycle length timer used during any call for heat. I'll see if I can watch it a little closer and let you know.