My Air Ease furnace, g2095c has stopped working. i have checked power and gas supplies to it - OK. The thermostat seems fine. The red led on circuit board is on and it's history diagnostics show 4 flashes - high limit switch open. High heat state green led is on. When furnace gets a call for heat from thermo the burners do light but it shuts down again after a few seconds and the fan/blower does not run. Also with the thermo set to continuous fan operation nothing happens. What other checks can I perform?

 

While the furnace is off due to high limit being open, check for 120 volts from the fan heating speed terminal on the circuit board. If you don't get 120 volts, the fan relay on the board is probably shot.
If you do get 120, it's likely either the capacitor on the fan motor or the motor itself is bad.

A quick & easy check is to turn off the power to the furnace at the switch or breaker & try to turn the fan by hand. Also feel the motor to see if it is hot.

 

Thanks Grady, Doubt if I could find the fan heating speed terminal but I'll look again. I suppose I'd ground one lead when checking? Actually I thought it was a DC motor - PCM variable speed. I can easily turn the fan by hand and the motor is not hot.
Either result I guess will mean calling Atlantis heating (orig installers) and hoping they don't soak me!

 

If you want to pursue the problem further..... post a picture of or the part number of the control board.

http://www.doityourself.com/forum/el...rt-images.html

 

best picture I could get in the restricted space and not all visible behind the maze of wires!I can't make out an obvious part number but installation manual shows P/N 46131-004. Thanks again.

 

Is your furnace model number G2D95C instead of G2095C?

 

oh sorry - need new glasses! Yes it is actually G2D95C

 

Thanks for clarifying. Does your furnace have a blower motor like the one shown in the attached photo? If so, here is a thread that may offer you some information and a possible solution:

http://www.doityourself.com/forum/ai...nt-turn.html#b

Here is a link to some good troubleshooting data:

http://yorkcentraltechtalk.wordpress...ooting-part-1/

 

hey thanks Firedawgsatx.
The motor looks similar but it's hard to see in situ. I will watch those videos and try it if I can get the motor out. As in one of the pics it is way at the back and I just don't know how I'll get at it. The manufacturer shows parts available from local dealers but only the complete motor is listed! As you say it's worth a try considering the new motor price; although mine was warranted {parts/labour} when I bought it 5 years ago. I decided the high cost of annual check-ups was not worth it and unfortunately I think that will void the warranty. Anyway I'll try tomorrow if i can survive the night here in Canada! Thank God I have a functioning gas firplace.

 

The module is the part that most often fails on that type of blower motor. As shown in the first linked thread it is often times the thermistor that goes bad. If so, it is a relatively easy inspection to perform. The thermistor is easy to obtain and doesn't take major soldering skills to remove and replace it. The second link shows how a DIYer can troubleshoot the motor using a meter. Part 2 on that link at: http://yorkcentraltechtalk.wordpress...ooting-part-2/ shows how to determine if the problem is in the motor or the module.

 

I don't think I can do it - replacing the thermistor is the easy part, getting the motor out is the problem. If I could get at the bolts attaching the motor to the fan housing how would I get the motor off the fan - there must be some firm connection between fan and motor shaft and that would be completely inaccessible. I wish I'd never had my old furnace replaced - it was simple and easy to work on and even if inefficient produced more heat and cost less to run!
At least I am really glad I found this site - thanks again Firedawgsatx.

 

There are usually just a couple of bolts you have to remove that hold the blower assembly to the rail in the cabinet. Once the bolts are removed it will just slide out. The control board has to be removed on some models or at least the control wiring disconnected. Taking several digital photos and good notes or even better having someone make a video of removal will help re-install the wiring.

 

I managed to pull the blower assembly out after removing the main control board and then removed the motor control module. I did check the motor as per that ECM troubleshooting page:
ECM Motor Troubleshooting – Part 1 | York Central Tech Talk [also part 2 ] and all appears good; however the 16-pin connector I was not sure about. Unlike the one illustrated the wires are not coloured (all brown instead) and I couldn't find pin1. So using one corner as pin1 I tested the voltage at all pins with thermostat set for heat, then repeated using the other corners in turn as pin 1. Nowhere did I find 24 VAC but several at about 28V
I should put the motor control module back and try the direct 24V input test - just to prove for certain that the motor won't run. See "Tech Talk: Troubleshooting an ECM 2.3 Variable Speed Module and Motor (Part 1) "
http://www.youtube.com/watch?v=YEzKU6_OKOI
Anyway I continued and opened the motor control module - one of the capacitors looks suspicious but how would that be tested? Now the thermistor is still in-place (appears OK) but measures 3Mohms between the leads. However it probably is open and the high reading between legs might be back through the circuit. I guess I'd have to unsolder one leg to properly test but am holding off at the moment until I determine that I cannot get a replacement under warranty. Very unlikely I think, even though it is just 5 years old.
But I'm sure the one capacitor is blown because it's coating is flaking off and the top appears swollen and there's browning on the board where it is soldered in.

 

With the capacitor top being swollen, you can pretty well bet it's gone. You would have to unsolder one leg of the thermistor to check it but chances are it too is toast.

 

I'm sure the capacitor and thermistor were both gone. but final result was that the motor was still under warranty so I put the controller back. The original installer got the warranty replacement but said he had to install it under the warranty and it was not negotiable - labour cost $350 + 13% tax! Got my heat back but now I feel burned, almost wish It had been out of warranty and I'd have replaced the cap and thermistor! At least I've learned a lot from this great forum.