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So far it sounds like a bad ignition control module, bad igniter, or gas valve.
If you can attach a well lit, well focused close up photo of the furnace wiring diagram, I can mark it up with trouble shooting instructions.
Use the paper clip icon at the top right of the tool bar for that.
We can go from there.
Hello again, generally you have to load the picture into your computer and post from there, that is especially the case with Apple products.
You can also post the picture to www.flickr.com and post the link to the picture here.
Thanks for the great pictures
let me know what you find, we can go from there.
Set the thermostat in heat mode and up to 90F for this test.
It might take a while for you to get parts for the furnace, it would help if you got her a couple of portable electric heaters and plugged them into separate 120 volt circuits for her.
The igniters fail frequently on those, see if you can pull the igniter out and look at it, if it has a thin black line across the face of it, its bad. You can also use an ohm meter to check across its two wire connections when it is unplugged and see if it has an open circuit or not (its bad in that case)
Check for 24volts across the low voltage transformer, if your meter reads 24 volts there, but not across the gas valve, then it is likely that the ignition module is bad.
I am sorry to hear that access is so bad, I spent 30 years of my early career crawling though attics and under houses to get to such poorly chosen equipment locations... One outfit dug a hole under a house to put the equipment in... the hole filled with water every year.
Let me know how all that goes.
Hello again, it could be a bad transformer but it is rare they fail that way, usually they put out 24v or nothing,..it is possible your meter read is off, due to poor contact with the probes or some other reasons, but still... it could be a bad transformer.
Most relays buzz a bit, I wouldn't jump to any conclusions on that basis.
If the gas valve stays open you will have a steady 24v across it...
we can get into the tall weeds speculating. It will be best if we get the igniter working first, then go from there. tell me what voltage you get to the female side of the igniter plug, be sure you have good electrical contacts.
we can go from there
Thanks for the pictures, the igniter 'looks' like its OK...I will be looking forward to your test.
You can fit a clamp around amp meter on the coil wire of the relay to see if it gets constant coil power, and you can remove the switch leads from it to see if the contacts are closing or not.
I will be here all day tomorrow.
You will have to wrap the wire you are testing around one side of the clamp in order to increase such a slight amp reading...you can splice in an extended wire to do that,...10 loops provided 10x the amp reading.
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