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Coleman pres II furnace/thermostat issue?

Posted: Fri Nov 26, 2010 3:02 am
by technodude60
HELP! :cry: I am not a guru when it comes to HVAC problems so here goes.
I am replacing the old honeywell round style thermo with a new digital one. It's a Hunter 44155c on a Coleman presidential II furnace in a older mobile home.
First off I have no idea,nor how to tell if this unit has a heat pump. I have installed the new hunter thermostat and the furnace will cycle on for 30 sec and off again. Temp is set to 68 and temp does not seem to go up. This unit IS working when a/c is on however.
Settings are as follows;
Thermo switches in the back are; STD/HP- on STD
Recovery- enable on
Fan - HG/HE- on HG

Wiring; G-grn
RC-jumpered with RH
RH-red
Y/O-dark green
W/B- white
Y1- no connect

I'm not sure what else I can add? I've read a little about the fan limit switches but I'm not sure where they are,or info on if there is a heat pump?
I have no diagrams/schematics as this would help!
Any ideas? Help!
Thanks in advance!
John

Re: Coleman pres II furnace/thermostat issue?

Posted: Fri Nov 26, 2010 8:14 am
by Greg
Lets get this moved to the heating section. Greg

Re: Coleman pres II furnace/thermostat issue?

Posted: Fri Nov 26, 2010 10:20 am
by technodude60
I thought I did post this in the heating / Coleman section?
?????

John

Re: Coleman pres II furnace/thermostat issue?

Posted: Fri Nov 26, 2010 6:23 pm
by Robert
Hi,

First, I would return the heat pump t-stat and get one for your a/c and furnace that is not for heat pumps.

Next, I would not get a Hunter, I would get a Honeywell or a RiteTemp.


Then I would trace the dark green back to furnace and see where it goes. May want to clean it off and see if it is really dark green.


Thanks,
Robert

Re: Coleman pres II furnace/thermostat issue?

Posted: Sat Nov 27, 2010 3:34 am
by technodude60
Thanks for the reply robert. I checked the book again for the hunter 44155c thermostat,and it states single stage heat pump- no aux.
Not designed for multi stage heat pump systems. Our coleman pres. II doesn't have a heat pump.
Is this thermostat still the wrong model? The dark grn wire I believe is from the compressor. This unit did work with the a/c on,but just turns on/off for no more than 30 sec increments even when set to "span3"
Thanks for your help again robert!
John

Re: Coleman pres II furnace/thermostat issue?

Posted: Sat Nov 27, 2010 10:50 pm
by Robert
Hi John,

Yes, it is a heat pump t-stat and you do not have a heat pump.



Thanks,
Robert

Re: Coleman pres II furnace/thermostat issue?

Posted: Sun Nov 28, 2010 10:42 am
by technodude60
Robert,
I failed to mention before that this furnace is the coleman presII Model 7600B.
I disconnected the hunter stat and bought a simple honeywell digital without the program feature and installed it last night. This honeywell is the model RTH111B. The furnace is still short cycling and will not stay on. I called a buddy of mine who used to have a mobile home with a coleman furnace,he said to look for a resettable limit switch on the top side of the blower housing? I saw a switch but it did not have the reset button. I did NOT take off the metal cover where the other components are,but I do have a vom and the schematic is on the cover.
Could there be a switch in there maybe?
Thanks!
John

Re: Coleman pres II furnace/thermostat issue?

Posted: Sun Nov 28, 2010 12:45 pm
by gordo48111
John,

Was it cycling ok this season with the old t-stat? If so, try reinstalling it and see what happens. Make sure the connections are correct. If you indeed do have a dark green wire that powers the outdoor condensing unit, it should be on Y or Y1. It may actually be blue and normally would be yellow. Are there any unused stat wires?

Re: Coleman pres II furnace/thermostat issue?

Posted: Sun Nov 28, 2010 2:22 pm
by technodude60
We changed the old round stat because the a/c quit. We installed the hunter stat then the a/c worked again,lol! So I guess we change stats with the season,huh?
Yes,the supposed dk. green wire is really blue. There is only a total of 4 wires. Red,green,white and blue,all connected. So now we have a no frills,non-prog. dig dispay honeywell model RTH 111B installed. We have no heat pump that I'm aware of.
ARRRRGGGGHHH!

John.

Re: Coleman pres II furnace/thermostat issue?

Posted: Sun Nov 28, 2010 3:34 pm
by gordo48111
So...the heat has not cycled properly at all since you replaced the t-stat, is that correct? Coincidental for sure. The RTH111B is not designed for a heat pump application. If you had a heat pump the outdoor unit would run during the heating cycle as well as the cooling cycle. As you did with the Hunter t-stat, read the instructions again to see if any DIP switches need to be set in another position - i. e. cycle rate for forced air gas (FG), fan - gas heat, etc. The next thing(s) to check would be the temperature rise across the heat exchanger. If it is too high (>70 degrees)the limit could be opening and closing which would cycle the burner off and on but the blower would continue to run. If this is the case check filters, blower wheel for dirty vanes, cooling coil for dirt-clogged fins and blower RPM. If the temperature rise checks out ok then ohm out the limit when the furnace cycles off. Disconnect power to the furnace and remove one wire from the limit when testing. If it is open when the furnace shuts down and closes after cooling off, with all other operations ok, replace the limit. There could be one on the wall of the combustion chamber and one in the blower compartment. If the limits are not open when the furnace shuts down it could be the t-stat, control board, or other problem that may require a tech to investigate. Robert should be back soon to add his expertise to your situation. I do have 25 years experience in residential/commercial/industrial HVAC/R but he no doubt has seen more Colemans than I have.

Re: Coleman pres II furnace/thermostat issue?

Posted: Sun Nov 28, 2010 4:59 pm
by technodude60
There is only one jumper in the back of this honeywell stat which switches the fan from gas to electric which is set on HG for gas.
Thanks for your help. I think this may be over my head.

John

Re: Coleman pres II furnace/thermostat issue?

Posted: Mon Nov 29, 2010 3:52 pm
by Robert
Hi John,

Some of the Hunter t-stats have to be set to HG for use with an electric furnace. So, set it to HE and see what happens.

If still the same, then it will take a total testing of each cycle and sequence to see what's up.


What is complete furnace model number just to be sure I have it.

I'm going to read all again and see if I missed anything.

I also do offer a email troubleshooting session one on one for a $20 fee IF you think it may help.


Thanks,
Robert

Re: Coleman pres II furnace/thermostat issue?

Posted: Mon Nov 29, 2010 11:36 pm
by technodude60
I installed a new honeywell stat as you suggested. The model RTH111B is inline with our Coleman PresII, model 7600B.
Thanks for the offer robert but I don't see how you could help further,unless you were here looking at it in person. Even with the new honeywell,the fan comes on from 30-45seconds. The pilot is on,but no heat.

John.

Re: Coleman pres II furnace/thermostat issue?

Posted: Tue Nov 30, 2010 6:09 am
by Robert
Hi John,

Then the t-stat is not the problem and circuits will have to be tested with meter to find the fault.


Thanks,
Robert

Re: Coleman pres II furnace/thermostat issue?

Posted: Wed Dec 01, 2010 6:34 am
by gordo48111
John,

It would have helped if you had mentioned earlier that it was only the blower that was short cycling but no heat. You first said that the furnace wouldn't stay on. Big difference.