Harman p61-a (10 yrs old) new circuit board question

Some background, I will try to be brief, my question will follow.


I Have a 10 year old Harman p61-a. Awesome stove. Over the 10 years I have learned a lot mostly here, but it's been a while. I'm very particular about keeping it performing like a formula one race car. I do a full clean about once a week. I like to see the flame so bright you see spots after watching it. I run only in stove temp mode, usually blower high. I measure my output temp with an ir heat gun on the same spot near centre above door by heat exchanger hole to ensure I'm where I want to be according to outside temp.
As the temps have gotten colder the last month, and I've turned to temp up, I've been having a problem with low heat output per what is normal for setting, weird feeding, ramp up to big flames, back off low, and repeat. Output temp varies by 20c. Normally it wouldn't vary much more than 5c. Also ash started staying in pot, overnight would fill up, somewhat lazy flame creating some and black soot on firebox. (I always try to keep it burning good to have white fluff on sides, I hate seeing black). Normally ash just stays in corners,unless stove needs a cleaning. Very rarely do I get any black soot unless stove is nearly maxed out a few rare extremely cold nights.
So this has been bothering me, I have been tinkering, checking seals, exhaust motor, cleaned several times over, switched probe, tried different pellets, everything I have encountered or learned over my 10yrs experience. talked to my very helpful dealer on several occasions. We ruled everything out, and decided to try a new board.

Well, I hooked the new board up and wow! Is there ever a difference. It is running WAY hotter on the same temp settings, and doing so with a much smaller flame. My concern is that it is running too hot, and I may have fluked out and got a dud board. For example, previously on my original board, pretty consistently on #6 I would read around 310c, this was my target on super cold nights. Well on this new board I'm hitting 310c at #4. To the other side, on #1 I would read around 140c with old board, new board 210c. I'm fine if it is just an updated board and things work differently and more efficiently. I just find it very strange that I'm getting an output temp on #4 that I would have previously got just below max. Also with new board on 4, flames are licking the exchanger, I don't know what they would do on max, I'm nervous to try. I know the esp will shut things down when it gets too hot, but I have a feeling that would be way before max setting on temp dial, unless of course my normal understandin for 10yrs was all wrong.

Maybe if anyone else uses heat guns they could throw some temps at me that they read on certain settings in stove temp mode, dist. fan high. Any feedback would be greatly appreciated.

Thanks

Golfeur said:

with the new board you adjust the air draft for the min and max value
min =, 35 H2o
max = .65 H2o

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That is good to know. My old board always was in the complete ccw direction. I started with new board in the same position, however it was lazy between feeds, and then would pick up at end of feed. I don't have a gauge to set draft, so I went all the way cw and it is working great. I have been slowly backing off and it appears to make a difference in flame height, even on high draft. I thought on the old ones the voltage adjust only affected low draft? I realize need a gauge to do it properly, but was not aware there was a low and high setting. I assumed it would be the same as the old one.

frankie said:

I also put a new board on my 61a 2 weeks ago and the difference is night and day. It is like they upgraded all the new boards. I also like that there is now an indent in the off position so you know it is switched off. I used to have use a flashlight to make sure the switch was in the off position when doing it at night. I run feed3 and stove temp 3.5. Gives plenty of heat.

I also have a magnetic thermometer stuck on the side and try to keep the stove at a comfy range.

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Do you notice a way higher heat output compared to your same setting with the old board?

I dunno, the more I watch the more something doesn't seem right. I cleaned stove today, and naturally it is running even hotter. Im on a 3.5 stove temp, feed 3.5 and she's burning nearly full bore, flames hitting heat exchanger and going across. To me it's running like it should on 5.5 or 6, heat reflects that as well. Also going through a bag in about 8hrs, which would reflect a way higher setting. Doesn't seem right to me.

Golfeur said:

Did you check if the dip switch 5 is in the right position if the dependent esp probe is red or black wire

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Yes I did, double checked. I have a copy of the dip switch settings from Harman and checked it a couple times. Gonna try my other esp tomorrow, it shouldn't be any different since current and spare worked the same on old board.

jackman said:

What happens when it runs in room temp mode?

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Haven't tried room temp yet, will try tomorrow and see what it acts like.

Well, I switched probes today, I took the brand new one off, and put a 1yr old one I had been using previously on my old board. It is not burning as hot as with the new probe, but hotter than my old board ever did in 10 yrs. the heat output, flame, and fuel consumption with new probe and new board was running equivalent to 2 full numbers higher with old setup. So a 4 with new would be = 6 old setup.
With new board, old probe it is in the middle, 1 number less than old setup. So a 4 would = 5 old setup. This seems more reasonable to me, with upgrades to the new board.
The new probe must be off? I have used a few probes over the years and they always read identical, unless they were toast, and then they were way wonky. I have one more really old probe, I will try tomorrow, hopefully it will read the same as one of the others.
I haven't got a problem with the way it's running now, but before it was way too hot, and on min setting would have run too hot for spring and fall. Tried min setting today with current setup and wasn't too bad, ran about 175c, old board ran about 145c, which is all I need in the spring and fall at night.