I have no power going to my Thermostat
I have replaced the thermostat and I have replaced the circuit board but still do not have any power going to my thermostat therefore my system stays running since the thermostat can not control it. What do I do?
Heating & Cooling - Carrier - 38CKC036 Air Conditioner
Answers & Comments
Hi,
If your system is running continuosly then you have power going where you don't want it too. If you cahnged the board and the t-stat then the next place to look would be the wire going to the t-stat. It has a short in it some where and that is what is making the system uncontroable.
Pull the R wire off of the board and see if the system shuts down, if so then you know it is from the board to the t-stat somewhere. If you pull the R wire off of the t-stat and it still stays running then you know the problem is in the wire between the board (furnace) and the t-stat....
Comment back to me and let me know what you find with this... and we'll go from there.
I hope that this will help you to solve your problem!
Thanks for using Fixya!!
Heatman101
I do have to run again... just poped in over lunch...
I will check on this agian later in the day and maybe another person will be able to help you more...
But let me know if you are in heating or cooling...
Also if you are in cooling does shutting pulling the disconnect on the outdoor unit shut down everything??
This will help to go further in figuring this out..
Heatman101
Okay, outdoor unit not running so you have to be in heating...
The problem has to be a relay in that cicuit board...
See if you can get them to give another one to try....
There is really no other place for you to be shorted out if you have the t-stat unhooked..
Heatman101
Remove the wires from the thermostat at the circuit board, they should go to the R and W terminals. If the unit shuts off, you have either a bad thermostat or a short in the thermostat wire. The furnace should only fire when the R and W terminals are jumped or the thermostat calls for heat. If it runs all the time, you have a shorted control board. Put a meter across R and W and check it for 24 volts AC. If you get zero, bad control board. There may be either a fuse on the board or in-line on some wiring. Check it. You may need to tape down the door safety switch while you have the panel off.