I have an Armstrong-Air Gas-Fired furnace G1D91AU and maybe a programmable thermostat. The system is around six years old and it has started causing me problems this winter. The system has been inconsistent when following the preprogrammed settings. It will NOT warm above 70 degrees no matter what setting. I have tried to use (hold and/or daily schedule) and neither one will work. The good news is that it will keep temperature close (within 2-5 degrees of the programmed setting). At first, I thought it was my old programmable thermostat (made by Hunter). I have since replaced that thermostat with another programmable (Carrier - Edge). The problem is still here.

I would appreciate any help!

Thank you in advance!

((I have an Armstrong-Air Gas-Fired furnace G1D91AU and maybe a programmable thermostat.))

Is it programmable?


The unit should run above the temperature you state unless.

Someone has added a limiter circuit to prevent the unit from going over a preset temp.

Air filter clan?

Since you changed the thermostat and a re knowledgeable on that subject remove and jump the heat only wires together to see if the unit will run at a higher temp. (this is just for test purposes to test the thermostat to make sure it is still not a problem.)

Buddharoo,

When you say "It will NOT warm above 70 degrees no matter what setting." does the funance turn off before this point, or does it continue to run?

You may have already done this but I'll still ask to be sure, had the filter been changed? Have you checked to make sure that nothing is blocking the exhaust or inlet to the furnace? Did it just start doing this, or has it been this way for a while?

Regards,

Eric D

First of all, thank you for the quick responses.

HVAC1000, it is definitely programmable and no one has added anything to the furnace. I do clean the filters on a regular basis.

Eric D, the system shuts off when it gets to 69 degrees and I do change the filters monthly. As far as anything blocking the exhaust/inlet, I will check this today. This problem just started a month ago.

Thanks again and any other thoughts would be greatly appreciated!

This will tell the tale.

Since you changed the thermostat and a re knowledgeable on that subject remove and jump the heat only wires together to see if the unit will run at a higher temp. (this is just for test purposes to test the thermostat to make sure it is still not a problem.)

HVAC1000, hopefully I can try this tonight. I will let you know the results.

Thanks again,

Buddharoo

I have the same, exact problem. Armstrong Air 93 Advantage about 5 years old, problem also started approximately one month ago, replace programmable thermostats as I also that was the problem, unit also shuts off at 69 degrees. No matter what I set the temp to will run to that temperature and shut off. Will be following this string and checking inlet and vent for blockage...

Any comments as to whether this is a good brand or not?