Coleman-Evcon Horizontal Gas Furnace CGH07512E
When heat is off, turning fan only on at the thermostat produces a click but the blower fan motor doesn't start.
The blower and motor turn easily by hand. With the side cover off, holding down the cover's switch produces the click, but the blower motor doesn't do anything.
When heat is on, raising the thermostat setting causes the correct starting sequence, including igniting the furnace, but it eventually shuts down because the blower doesn't start.
I'm very grateful for any help.
I had to change the controller card (printed circuit board) once to correct that problem.
I would have sworn it was the blower motor, but last night a technician traced it to a circuit board malfunction.
If I can't find a better price, I may try to replace it myself. I suppose if I get the identical board and do a wire-for-wire switch, I should be okay. (?)
Take a digital photo of the board and/or draw it on paper and shut the switch before you disconnect the wires. Sometimes the replacement boards are not exact and you have to go by the markings on the contacts. For example, the one I did had the accessory contact for the humidifier in a different place.
New circuit boards often vary from older boards as manufacturers make changes of various kinds. There usually are not instructions provided if it's just a circuit board ---- if it's a packaged ignition control module made by a separate manufacturer, there may be detailed instructions you might find hard to understand.
Being able to adapt a new board to an existing installation is one of the things furnace repairman get paid to be able to do. You have to decide for yourself whether you have the competence and experience with your furnace and how it works to do the job.
Keep in mind that this is just the kind of task that the manufacturer would recommend against you doing.
Originally Posted by Ktuck
I would have sworn it was the blower motor, but last night a technician traced it to a circuit board malfunction.
Ummm. So far your diagnostic skills weren't up to the job. Are your skills in choosing and installing new parts likely to be better?
I'm not telling you what to do, but simply raising issues you should consider honestly and carefully.
I might add that I've polished off more than one car by my own incompetent auto repair efforts. It's not a matter of ego, or desire --- it's a matter of experience and competence that you need to evaluate.
Well, I guess I beat the odds. There was some confusion in finding the correct Honeywell universal board that has replaced 25 or so older boards, but the stars aligned and I'm sitting here in a warm house.
The old board had a burnt area underneath one of the relays, so that was obviously the problem. The new board was a direct terminal-for-terminal replacement, so I didn't have to stretch my intellect too far. Basically a plug 'n play replacement once I was told what the problem was.
Glad things worked out. Sometimes we hear back with tails of woe, so best to have people think things out with some care before going ahead.
Agreed, particularly in working with something like a furnace, an area where I have absolutely no experience to draw on.
In this case, I think it worked out because I stepped aside to let an expert diagnose the problem, found another expert to advise me on the best inexpensive solution, and then lucked out to find that the actual fix was pretty easy.
Watching the technician diagnose the problem; it looks pretty simple, IF you understand the logic and sequence of each test. I don't, so there's no way I could do a reasonable diagnosis. If I had no other resources, I might have replaced the blower motor and capacitor before I even looked at the circuit board.
Thanks again for the help!
Originally Posted by Ktuck
Watching the technician diagnose the problem; it looks pretty simple, IF you understand the logic and sequence of each test. I don't, so there's no way I could do a reasonable diagnosis. If I had no other resources, I might have replaced the blower motor and capacitor before I even looked at the circuit board.
In my view, the most important DIY skills is being a good judge of what to try doing and what to leave to a pro.
The other important thing is that a DIY repair typically doesn't get needed cleaning, maintenance and safety inspections done on furnaces. MANY time when I was a furnace repairman I repaired a problem that caused the furnace to quit working, and also completed past due maintenance and inspections. Sometimes such things can be critical safety hazards.
The DIYer may be able to identify and repair a critical repair that is causing the furnace not to work, but are often going to be unable to recognize safety hazards or appreciate what maintenance is needed.
Yep, that's why I didn't hesitate to have two extra sets of eyes on my job. The more experienced of the two, who had been in the heating business forever, thought things looked fine just the way they are.
The younger guy thought things looked okay, but was very concerned that my filter wasn't expensive enough (it looked adequate to him, but he wanted to show me a better one), thought that a trained person should be in charge of checking the filter every two months, and was generally convinced that my life would be empty and meaningless if I didn't join their heater maintenance club (which would give them the opportunity to come by and try to sell me filters every month or so).
This is the same guy who diagnosed the problem, but then told me it would cost over $900 to replace the circuit board (which cost $100 and took less than an hour to do myself). I kept asking him about getting my heater going, and he kept asking me how I felt about joining the club and having access to some really good filter products.
These two guys accurately represent my experience with this industry. Lots of hard-working experienced technicians who respect the intelligence of their customers and want to keep them happy. Along with a large number of snake oil salesmen who rely upon the naivety of their customers and who would be equally content as a service manager at an outrageously priced auto dealership.
If the first technician had been honest and prepared to fix the furnace, I would have gladly paid $350 to $400 to have it done then and there. The service company would have made about $300 for an hour and a half of time and I would have been very happy.
Unfortunately Ktuck, your experience seems all too common.
In my years self employed as a furnace repairman, I decided that the two most important things to look for in a service provide were 1) honesty and 2) competence.
I recommend asking around among friends, neighbors, relatives and co-workers to find service providers of any kind who are honest and competent.
And personally, I favor cheap $1 filters from Home Depot or wherever unless a family has one or more people with breathing problems.
Tags: blower, start, coleman, evcon, furnace, blower motor, circuit board, would have, diagnose problem, furnace repairman, before even, before even looked, before even looked circuit
