To BCC3 Control Board, or not to BCC3 Control Board
December 3, 2013 10:30 AM   Subscribe

A question regarding an impending attempt to replace the control board in our furnace myself. Extenuating circumstances: Approaching Arctic Cold Front.

The story so far:
~ Furnace breaks down: fan won't come on.
~ Repairman comes and diagnoses problem: Control board frizzed
~ Good news: We can use furnace by keeping fan turned on all the time. Heat cycles normally.
~ Kind repairman mentions: I can find a control board online and replace it myself for WAY cheaper ($118 vs $900+)
~ Control board ordered and will arrive tomorrow.
~ Arctic Cold Front will also arrive tomorrow with temps close to 0 degrees.

So... I'm pretty confident I can replace this thing. It appears to be simple moving of connections to identical connections on the new board - one at a time so there's no chance for mix up.

But, I've never done it before. AND, it's going to be big-time-cold tomorrow when I get this board.

My options:

1. Go for it, and hope it works. If it does not, I'll be without heat. I can try to replace the old board and restore the limited functionality we have.

2. Wait for a week+ for warmer weather (predicted) and do it then in case it's a bust.

Furnace saavy Mefites: Have you ever replaced one of these thangs? Do you know the ways of furnaces? What do you suggest?
posted by ecorrocio to Home & Garden (7 answers total)
Response by poster: Should also add... keeping the fan on all the time is a pain. Especially at night... and will be bothersome during the upcoming cold snap.
posted by ecorrocio at 10:32 AM on December 3, 2013

Provided I have the power well and truly cut to the thing while moving connections and such around, I'd be comfortable giving it a go myself. Take pictures of everything throughout so you can put it all back if need be.

Was the $900 for parts and labor? Or just the part? What about having him install the board you bought?
posted by jquinby at 10:35 AM on December 3, 2013

Response by poster: jquinby: Their stock price for control board replacement was $960. How they get from $118 for the board (even less wholesale) to $960 is beyond me. My guess is it's a 15 minute job. I didn't feel I could ask him to install. He works for a big-ish company and said "you didn't hear this from me but you could buy this online etc..."
posted by ecorrocio at 10:39 AM on December 3, 2013

Are there any capacitors to deal with? There were a couple on a combo furnace/AC unit at our last house that were just a bit smaller than Red Bull cans. That'd be about the only thing I'd hesitate on, since they need to be discharged or they can be dangerous. They were outside, close to the compressor side of things.

But if it's just unplugging the old board and plugging in a new one, I don't know why not. Our new place has a pair of heat pumps and there are apparently magical crystals or something inside them because everything they touch becomes a gigantic pain in the ass.

Take care to tighten all the sheet metal screws that you have to undo to get to the guts. Leave one loose and the thing will rattle all winter and it'll drive you nuts.
posted by jquinby at 11:02 AM on December 3, 2013

I've done this, or something similar enough. Wasn't replacing the whole board, but replacing a component that controlled the fan (same as yours, the fan just stayed on instead of cycling with the heating). Took pictures as I went, made sure to match it all up putting it back together. It is definitely not rocket science, and for $800 is something I would totally try to do myself instead of paying for.

The approaching cold is a unique wrinkle. Here's my thought: how much of a burden is it to remember to turn the fan off and/or how uncomfortable (dry air) will you be for a week if you don't do this tomorrow. Me personally, the dry air would be a pain and I'd give it a try to fix myself tomorrow. Between waiting or not waiting, and failure/success I see four outcomes:

1. Wait, do the work yourself, fail - have to pay someone to fix it, frustration you waited a week
2. Wait, do the work yourself, succeed - frustration you waited a week
3. Don't wait, do the work yourself, fail - have to pay someone to fix it
4. Don't wait, do the work yourself, succeed - woohooo!

If you do it yourself and fail you're paying either way. If you wait, regardless of failure/success you're frustrated you waited a week.

I'd probably just do it, rather than wait a week. But if it's possible it will start to warm up in a day or two, then maybe "start" to wait and see how bad the fan 24/7 is to you, and if you can continue to wait a couple more days.
posted by ish__ at 11:05 AM on December 3, 2013

Go for it, but seriously consider doing it *after* the storm. One rule of home repairs is that you should not interact with an essentially functioning critical system like heating, air conditioning, plumbing or electrical when there is a hard deadline coming up.

You can reconnoitre the situation during the cold snap and formulate a battle plan. Attack if it appears to be an easy victory, as long as you are sure that you can retreat safely. In this situation, not losing is as important as winning.

Start your replacement early in the day: it's almost always warmer during the day than at night, and you want to be able to observe the operation of your heater for a few hours before you trust your sleeping self to your new circuit board friend. Sometimes new parts fail a few hours after they are installed.

I've replaced circuit boards in a home furnaces and RVs. If you have an exact replacement, things are better. If you have a generic replacement, sometimes it doesn't work (I'm talking about a Dinosaur board for an old, old RV heater: the ignition device crashed the circuit board intermittantly). If the the furnace is old, sometimes the act of removal can damage the existing functionality.

Sometimes professionals will misdiagnose your problem. I am suspicious, in your case, that the problem might actually be the fan thermostat and not the circuit board, in which case you could end up with a new circuit board that works no better than the old one. You're so far ahead of the cost of the retail repair, though, that the hundred bucks is basically noise even if it doesn't fix it.
posted by the Real Dan at 11:39 AM on December 3, 2013 [1 favorite] much of a burden is it to remember to turn the fan off and/or how uncomfortable (dry air) will you be for a week if you don't do this tomorrow...

If the fan doesn't blow over the heat exchanger, the exchanger will overheat and the thermal cutouts will probably cut in. This is probably the "breaks down" part of ecorrocio's description.

I'd just keep the fan on. I tend to let mine run during cold spells, it keeps the heat more even around the house.
posted by JoeZydeco at 11:51 AM on December 3, 2013

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