Basement air not coming on
- Thread starter Dibbs49
- Start date
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If you have answers, please help by responding to the unanswered posts.
If you have answers, please help by responding to the unanswered posts.
Neal
Well-known member
With the air turned on and the house 12 volt turned on, first check to see if contactors are closed. If open, then check for low voltage between the common & probably yellow (wire coming from the t-stat). If no low voltage here, check t-stat. If low voltage is here, check at coils of contactors for low voltage.
John Canfield
Site Team
There's good service documentation on the Airxcel website for the heatpump and thermostat.
John Canfield
Site Team
It should be a heat pump. On my website RV pages I have truth table of what voltage should be on each lead to the control board of the heat pump. Look at the link to the Colman-Mach thermostat upgrade to an ecobee smart thermostat.
Also in the service manual is a description of what LED should be lit on the control board for certain operating modes.
Also in the service manual is a description of what LED should be lit on the control board for certain operating modes.
The model # of ac unit is 6636A871, the tstat I replaced that was in the coach when I bought it is 6636 345. I got on the airxcel web page and one states the 345 and another states the correct tstat is 6636 341. Can anyone share any insight on which tstat would be the correct one? Thanks
John Canfield
Site Team
Before you start replacing parts, you need to check voltages at the thermostat. Use my truth table to verify +12V is going to the proper lead (and then to the control board.)
On the bottom of this page are some links to useful resources.
On the bottom of this page are some links to useful resources.
All readings were taken at the 9 pin connector going into pcb. With cm mach tstat in cool auto fan mode, red wire 12v, yellow wire, to comp. 1. NO VOLTS, note, fan will come on when switch moves to fan on, both high and low, but not in auto, my unit # is 6636A871, 2stage cooling and gas heat, i do not thing this has an heat pump. Furnace works great,
Neal
Well-known member
I would then try to check yellow wire leaving t-stat, if NO volts, then check red wire into t-stat, if YES, then something probably haywire in t-stat.
John Canfield
Site Team
On the thermostat wiring, jumper P2-2 (red) to P2-5 (yellow). This puts +12v on Y1 (compressor #1) and signals the control board on the basement unit to start the compressor.
John Canfield
Site Team
Sure sounds like a bad thermostat.
