Harman P68 did not shut down

Last night the stove was on Room Temp / Auto to take the chill out of a cold and windy night. We went to bed and turned off the stove.

This morning the first floor was much warmer than I expected when I got up-checked the oil burner thermostat-that was down. Listened in the basement door and heard the stove running low. Figured I did not get the Off position right-but it was in the right spot.

Dist blower was off but it was still feeding small amounts of pellets keeping the fore going low. The feed cycle was not a shutdown cycle. The was more frequent.

I had a similar issue 2 years ago that started at almost the exact point in November where the stove would shut down but the motors kept running.

Harman P68 issues | Firewood Hoarders Club

That appeared to be a dirty potentiometer so I turned the pot a bunch of times to try and clean it quickly. Didnt change so I turned the pot a bunch more times again, no dice.

The stove ran out of pellets Friday night while burning and I just left it be and turned the pot to off. This was the first time firing since then so thought maybe it was a glitch requiring a reset. I unplugged the stove for a minute and plugged it back in. This time I confirmed that the dist blower came on when put back in Room Temp and Stove Temp and that the dist blower went off in Off mode. Worked as it should and the stove shut down properly.

A bag of Infernos that I was informally testing is what it cost me.

I will keep a close eye on the shutdown and make sure it is resolved but in the end I wont know if it is a dirty pot again or a reset issue.

Any thoughts to test are welcome.

 

yea, good place to start, as Jay says, try and clean the pots, unplug the CB, replug it in....beyond that, new CB.

 

Don't have a clue about test - the dynamic duo of LW & JT got 'ya covered there -

will only mention it was 'wicked' windy the past few days, power dipped here several times - maybe contributed to 'glitching' the stove?

 

I always like to see draft figures and DDM readings, but alas, no one owns those things, so, I am afraid to ask!

 

BEER

 

mines turning white, with a severe thinning at the back crown of my head, thank you very much!

yea...theres a bolt on the P-series on the left hand side of the base, near the back...you wont see it unless youre on your hands and knees looking for it. Remove the bolt- that's where you take your readings! We are slowly going to digital draft gauges. Soon, though, the P-series units will have a draft port right on the circuit board! Will be so much easier to set readings! Just don't lose the port cover.......better stock up on some of those, I guess.

 

OK, regarding cleaning a small, sealed potentiometer. Whats the best way to try this and what contact cleaner is safe for the plastic?

Do I remove the board from the labeling plate and clean from the shaft side or from the back body side of the unit?

 

Actually it doesnt look like removing the board from the plate will grant me any batter access. There are 4 small openings (1 on each corner) of the pot with a metal tab in them. Is this an reasonable access point for cleaner?

 

Thanks J.

Yeah the access points in the pic of the pot are what I was talking about. I went by a local Aubuchan Hardware earlier today but they had no contact cleaner-the worker didnt know what I wanted but she was eager to see if they had it. Give her credit for trying.

I just cleaned up the contact pins on the multi connector best I could with some fine sandpaper, blew out the pots and turned them a bunch of times. I will get some contact cleaner but this will hopefully take care of it.

 

gbreda, DeOxit cleaner is good stuff to clean Pots, have used it here ..



Edit: DeOxit F5 cleaner, available on Amazon.

 

Now that you mention it, I was having quick brown out like drops all day as well on Saturday. My battery backups on the computer and modems were going into backup mode and beeping for a quick second on multiple occasions. The stove is on a good surge protect but that doesnt help voltage drops. That may be a factor here...good call !!

The stove is running now-not that cold but more for a shutdown test in a bit.

 

Yup, same here.

But I'd still do the cleaning suggested, anytime you can get by w/ some minor normal pre-season maintenance, that's a beautiful thing..
(My eyes are bloodshot and bleary from staring at fire the past 4 nights, trying to tune the burn on the stove here.)

 

So true

Id rather it be a problem now than in Feb. Then again, it never shuts down in Feb so it wouldnt even be noticed

 

Gino, I've had this issue too. I discovered that some times when I turn the stove off the Status light stays lit and the stove doesn't shut down. I now make sure the Status light goes out and all is well.

 

Turned off the stove and made sure the Status light went off as subsailor mentioned. All worked properly.

Regarding the status light, on Sunday morning I dont recall if the light was on or off, but the distribution blower would not come back on when the knob was turned back into Room Temp or Stove Temp until I unplugged the stove for 30 seconds and plugged it back in.

Now the stove was burning at this point so I dont know if a reset actually occurred. I did leave it unplugged all day, so a reset should have happened for sure then.