Accentra help before I call a tech in??

[glockshooter]

Merry Christmas or a Happy Hanukkah everyone first of all. I'm having an issue with my freestanding Accentra that I can't nail down. I've got an idea or two, but want to get your opinions before I have to call tomorrow.
The stove is about 12 years old. No parts replaced except for an igniter 4 years ago. It's been a bit off for about a week now. Turned it off before bed one night this week thinking it usually takes an hour to burn down and cool off, then shut off entirely. Got up in the morning, it was still going low, but the control was set solid to off.
That night, it started fine, a bit slow, but it lit on it's own. Now I get a nice rolling fire for a bit, then it just lets the fire burn down low. I'm getting an occasional flutter or vibration on what I think is the exhaust blower fan, it doesn't seem to be the distribution fan, but that's just my opinion. I cleaned it well 2 days ago to no change.
Then to top it off, today i'm home, house is quiet, stove is set dead off, and i hear it start feeding and stuttering the blowers. The whole board lit, gave a few seconds of work, and went out. That repeated a few times.
No error blinks or obvious issues to correct.
I'm thinking I should get a tech out to diagnose this. I'm preparing myself for at least a control board, possibly something in the blowers?
Anything I should check before I call the pros?

 

[jzm2cc]

Dirty exhaust probe possibly, but no fault codes, hmmm. After 12 years a board going bad is not far fetched, but Exh probe might be a good place to start looking.

 

[glockshooter]

oh, and I did notice there seems to be a dead spot when I turn the dial to room temp in a certain spot. It's like it's just a dead range. I have to pass it to get any power out of it.
I gave the probe a decent brushing, it didn't look bad, but maybe I'll pull that tomorrow before I call. The starting from off just has me focusing on the board.

 

[jzm2cc]

Well there you go, sounds like hit and miss contacts within your potentiometers. Several on this forum have used electrical contact cleaner to fix up and prolong their life. I've replaced a few in the past on older boards. Worth trying a cleaning with board unplugged from stove.

I imagine the control board has fits when it sees resistances outside the normal 100,000 ohm range of those pots.

 

[jzm2cc]

Guess thats why i use a thermostat to control stove instead of playing with potentiometers which are a definite wear item.

 

[Bioburner]

Stove starting on it own, been there done that. Bad pot switch on the board. First Harman stove I put in the garage. Put all new switches on the board and no other issues before I went and disassembled for rework. Sold it and other than the party calling wondering why it would not start(didn't turn the temp switch up) never heard from them again.
Set of three pot switches off ebay are around $21. Need to be fair at soldering or find a computer or cell phone repair so don't cook the fine traces on the board

 

[glockshooter]

Stove starting on it own, been there done that. Bad pot switch on the board. First Harman stove I put in the garage. Put all new switches on the board and no other issues before I went and disassembled for rework. Sold it and other than the party calling wondering why it would not start(didn't turn the temp switch up) never heard from them again.
Set of three pot switches off ebay are around $21. Need to be fair at soldering or find a computer or cell phone repair so don't cook the fine traces on the board

I'd be hesitant to try that. I can solder wires, but circuit boards are probably above my level. Any benefit to getting a new board? Does the software or anything change over the years?

 

[jzm2cc]

Yes software would be different based on your stove, usually an improvement with reaction times (BTU ramp up times).

About $200 for new board on ebay with free shipping. Then swap it out board and buy potentiometers off of ebay for old one. Find an electronics repair shop that can change them. Easy for someone with circuit board repair experience. Nothing like having spares since these Harmans last so long.

 

[rickwai]

On older units that need circuit board replacement, I also replace the ESP at the same time. At that point you have all new control components in the stove. It ends up being a better service for the customer do to there is no added labor to do ESP and if it eliminates a service call and labor from a call back it is well worth it.

 

[Bioburner]

Good point and the stove is 12 years old

 

[glockshooter]

switched it over to stove mode this morning. Started maybe a bit slower than I was expecting, but it's been running great all day. Does that rule anything out? I didn't expect it to be burning this well. Nice rolling flame, blowers nice and steady.

 

[Bioburner]

That switch is the one that gets the most work so may run well in that position for awhile. Rules out issue with ESP but if one had 12 year old tires on a car and one blew, would you just replace the one and wonder when the rest are going to go?

 

[glockshooter]

that makes sense. just want to make sure I replace the correct parts, I hate it when the only solution is throwing parts at a problem. thank you!

 

[Harman Lover 007]

Check and make sure your room sensing probe connections are tight. You probably have a dirty pot but what you describe could also be a bum signal from the probe.

 

[glockshooter]

Is any place better than the next in regards to ordering parts? Control boards seem like a solid $196-204 across the board.

 

[Bioburner]

About right. $200 average. I am told that the new boards prefer the red wired ESP so add that on too.