Harmans (P68), Super Premium pellets and black soot

[gbreda]

I am having an issue with super premium pellets (Okies) producing black soot on a high burn only. This has all the feel of fuel/air ratio. realize that there is no real high burn adjustment on a Harman.

My set up: out of the stove to a T (3 inch venting); up 5 feet to a 90 deg and then horizontal vent out 36" from outside wall. OAK with Harman thimble at the top of the 5ft rise.

Stove Temp 4, feed rate 3.5-4 produces no soot. Stove temp 5, feed rate 5 produces alot of black soot in the fire box. I can even see smoke inside the fire box.

The stove is completely cleaned before changing from Greene Team (hardwood) to Okies (softwood). 1.5-2 tons Greene Teams did not produce this. Venting cleanied with a Lint Eater. T emptied, ESP removed and cleaned, exhust tube from fire box to venting cleaned after esp removed, air flap freely moving, both blowers clean as a whisle.

Reading other posts, there are others having the same issue. newf lover has posted in another thread the exact same issue.

I have checked the wall voltage 122V. I have checked the leads to the combustion fan in test mode (which I would assume simulates high burn voltage) and that is at 122.3 as it should be.

Here is the kicker. I left this morning with black soot on the fire brick and walls of the firebox. Turned the stove to stove down to temp 4, feed rate 3.5. Came home to a completely clean stove. The low-mid burn burned off the soot.

Any other Harman owners or techs have any clue on handling this?

edit: had incorrect feed rate settings posted: adjusted..........

 

[Lousyweather]

I think first thing I'd do is check the intake damper, set the feed rate to 3-1/2 and dont change it EVER AGAIN. Also check for obstructions in the thinble or the intake screen

 

[gbreda]

Intake damper moves freely. No obstructions in thimble.

I have read many different thoughts on the feed rate of a Harmon in Stove Temp mode, but I can't argue with someone that works on em.

3.5 feed rate....check.

 

[jtakeman]

Geno,

How is the new setting burning for you?

Keep us posted.

jay

 

[gbreda]

Hey Jay

It's doing better with lower feed rates than the Greene Team needed. Still adjusting to get the right burn for the Okie. Seems to like it around 4.

I have spoken with 2 Harman techs (dealer and independent installer that is a Harman trained tech). Both said that the feed rate often needs to be adjusted when changing brands. Especially going from a hardwood that averaged 1-1.5" pellets to a softwood that is averaging .5".

The dealer tech also mentioned that they had the exact same issue with a Harmon PC45 in the showroom. Put in a bag of Okie and the firebox soot-ed right over. They sell Okie, Dragons, NEWP plus one more that I cant remember there so he was not sure what was in in before the Okie. Adjusted the feed and 2 days later it cleaned itself up. When I mentioned that the soot on mine is happening on a high burn, he told me to crank the stove all the way up for at least 30 minutes, then dial the feed rate back to get the proper max burn rate. I knew the manual instructed to get the burn 1 inch from the edge of the burnpot on high, but did not know to let it crank 30 minutes first. Will be doing that adjustment tonight.


Geno

 

[gbreda]

Well, feed rate of 4 is it. Great burn, no soot and mega heat
Set it and forget it for the Okanagans.

edit: that is until another brand of pellets goes in ;-)

 

[gbreda]

I knew the manual instructed to get the burn 1 inch from the edge of the burnpot on high, but did not know to let it crank 30 minutes first.

Ummm, I just found the 30 minute instructions in my girfiend's XXV manual, so looked at my P68 and sure enough, Page 16, Hint # 7 spells it out. DOH ! :red: