Lennox 80MGF continuous fan won't work


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Old 12-04-09, 01:38 AM
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Lennox 80MGF continuous fan won't work

I have a Lennox 80MGF2-60A-5 gas furnace. It was installed in October of 1996.

I have successfully replaced the existing original EGC-2 circuit board (28K62) with 17W82 (ignition control conversion kit LB-91097C), which is an EGC-1 board.

One little issue I'm hoping someone can help me with. Everything works except my Fan, when set to continuous 'on'. The unit works great when a heat demand is being called for by the thermostat, but when I turn the Fan to 'on' instead of 'auto', I hear a click from the unit and nothing happens. No diagnostics on the LED's either.

When I replaced the 28K62 with the 17W82 I marked all wires and made sure they all went to the appropriate place on the new circuit board.

One thing with the new EGC-1 board, it comes with a continuous fan jumper that is per the manual that came with it...quote.."used with EGC-2 units converted to EGC-1". The new circuit board instructions say 'do not install jumper if continuous low speed is installed, either at the ACB LOW terminal or to a separate circuit controlled by terminal G of the thermostat.'

My thermostat does have green wire that went to the old G terminal on the original circuit board. So I did NOT use the continuous fan jumper that came with this kit. I just hooked the green wire to the G terminal on the new circuit board as it had been on the old board.

Any ideas why the continuous fan will not operate and I just hear a 'click'? The fan worked when set to "on" with the old circuit board.

Thanks.
 
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Old 12-05-09, 10:56 PM
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It is working now. I used the 'continuous fan jumper' from ACB HEAT to ACB LOW and it it works. I hadn't fully read the instructions...duh!
 
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Old 12-05-09, 11:04 PM
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Glad that you got it going.

 
 

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