No heat...still

[mainah]

The red wire is the power feed to the t stat it picks up power at the control board the white wire tells the controller it needs to make heat. That does not mean the have not been reversed but one has to start with power. From what I see there is a reset breaker (like a push button) some where in the mix and the power feed comes from it.

[JohnB]

Originally Posted by Jay

Thoughts? Am I sniffing closer now? Is it possible to have a junk Tstat wire from ac to furnace?

Thanks again,
Jay

Just throwing this in the mix so you know and to your question.

"IF" down at the furnace you find the T stat wire that feeds the blower relay coil to be dead then that is a problem. And if you unhook that wire and temporary jump 12 volts to the relay coil and the furnace runs like it is suppose to, then the T stat wiring or T stat is having issues.

Now to the AC unit and your question. There is a saftey in the AC unit that will not allow the furnace to run if the AC unit is on. Remember when you where trouble shooting the AC unit and found the lizard in there....

Here is the AC board. See the furnace terminals in the top left



On mine there are 2 blue with a white tracer plug on them. Look to the left for the blue and white tracer wires


You can see they wire nut to 2 black wire and head to the furnace


The T stat wire are there too


Point I'm making here is, there is an AC interlock that can hold out the furnace. Your furnace is a little older than mine and we do not yet have pics of your relay setup. On your vintage they may have run the T stat wire from the wall up to the AC, through the interlock and then down to the furnace relay.

While you may have voltage at the T stat heat wire at the wall, if the AC unit is in the mix it is another area to check were are you loosing the signal on the way to the furnace.

[JohnB]

Originally Posted by Jay

The relay that is mounted to the top/side of the blower motor. Can just that be replaced? Sitting in a snow bank today playing with it. I've volt tested everything in there with 13 volts in all connections. On that relay if I jump the top wire which is hot to the bottom that goes to the motor it fires right up. I turned the gas on jump the wire and she fired up.

So I guess I'm at the point of. Is it my board not telling the relay to make contact? Or is the relay no good?

Thanks,
Jay

Jay,

Need to you confirm how you jumped the system and it ran.

You said you had 13 volts on "all" connections? Does this include the T stat wire heading to the relay?

At this point need you to confirm "yes", I have T stat power at the furnace or "no" you do not.

If there is no T stat power, then that has to be tracked down. If you do have T stat power at the furnace then something is holding out the fan relay or the relay is bad.

Before I would go all up in the AC unit etc, need to confirm the T stat signal is or is not present at the furnace.

Good luck, your doing good.

John

[Jay]

Ill pulled apart the bunk. Tested there. The red had power. Went to the control board, no power there.

So last night I took two long wires undid the tstat wires at the furnace. Ran two jumper wires to the control board. Turn the heat on and turned up the temp. Heard the clicks, few seconds later the furnace kicked on!

So my new mission is to grab tstat wire tonight. Saturday before I head up to the sugar house my plan is to some how snake a new wire from the ac to the furnace.

Thanks for all the help!
Jay

[JohnB]

Great!!! Most trouble shooting is a process of elimination.... Just sometimes, the hope is it comes sooner rather than later....

May the heat be with you...

[Jay]

Now it's on to the rest of the fix it list. Then a good spring cleaning all before the end of April.