26VAC reaches heat exchanger...but...
I have a heat exchanger outside that is not working--no fan, nothing.
When I switch the thermostat to "AC" after a few moments the house fan goes on and at the same time I read 26VAC right at the heat exchanger outside--the same two wires that left the thermostat and arrive at the heat exchanger.
The thermostat signal is getting to the unit. I also read 240VAC on either side of a relay which is under the cover of the unit. I can see that this relay is not closing when the 26V signal arrives.
But the 26VAC does not go directly to the coils of the relay that starts the unit, there's something in between:
There's a device between the input 26VAC signal and the coil of the relay--it appears to be a heat sensing device because one side of it is attached to one of the condensing coils. One of the 26V wires goes through this device on the way to the relay coil.
As a troubleshooting question, can I run a jumper over this device long enough to see if the relay closes and the unit begins functioning? That would mean a bad...I'm assuming it's some sort of thermostat...device.
If that's not safe, any troubleshooting suggestions?
Edit: and by "safe" I do not mean safe to life and limb. I'm being very careful around the 240 Volts. I mean, is it safe on the hardware to do this test...
Last edited by quivil; 03-16-2012 at 06:43 PM.