Howdy, I'm Dave from WV. I'm an HVAC contractor and part-time local pastor. And I have a question.
I went out to service a mobile home furnace, which was a Miller MGC-80-1. And when I got there, it was working fine. Actually I have never been able to catch it acting up yet. So...........
The problem is that the blower kicks on and off during the heating cycle at random intervals. I learned this from the customer and also by hearing it for myself as they held the phone up to the furnace while it was acting up.
When I was there the first time, I cleaned the motor because it was caked with dust from years of not having a filter. I thought maybe the lack of airflow in the vent holes might be causing the motor to overheat and trip the overload. But it still acted up.
Right off the top of my head, 2 conclusions come up, bad motor or bad fan control. Problem is, without being there to check and see if the motor is getting voltage during the down times, it's hard to tell which one by guessing. Like the saying goes, it's hard to fix something when it's working.
I came across this site when doing a search for a wiring diagram and figured I'd pick your brain in the process.
So ......... any ideas or suggestions???
Thanks in advance.
ETA: Also, there is no set pattern as to how long the blower runs or how long it's down when it quits.