Burn pot fire dance

Yes.

 

Sorry from the other side. Wood stove over hear, I LOVE BEER!

 

You're gonna feel right at home over here then!

 

Did someone say BEER?

 

Slurp beer

 

No worries!

 

X2 Welcome to the "other side" Thor

 

x3 - Welcome, and no apologies necessary: we're all (well most, anyway) Pyromaniacs here also.
* Watch out for the Bear, he's the worst offender.

 

TT, when I've seen that "dual flame" behavior here: it's due to lack of airflow, and the burn pot is typically choked w/ pellets, and airflow through the burn pot is restricted. So ..

Cleaning the burn pot, down to bare metal, including using a drill bit to clean the air holes,

Inspecting the pellets burning in the current batch for length / moisture change, adjusting feed trim rate, opening a pellet bag a day early inside, and letting them 'breathe',

Inspecting the Air Intake section & OAK, including using the air compressor to blast that section out / verify no obstruction,

Deep Cleaning:

Inspecting & cleaning the Heat Exchange assembly (including using compressed air) / the Firex panels / the lower combustion chamber vent ports behind the panels, leading to the combustion blower,

Inspecting & cleaning the Combustion Blower,

Inspecting & cleaning the Exhaust Smoke Probe (aka "ESP"),

And brushing out / cleaning the attached venting are all things on the list of things to do here.

FWIW, neighbor up the road was having 'burning issues' awhile back - it turned out to be the Combustion Motor was getting tired. I'll check w/ this week & ask her to confirm this - CRS has set in. Again, I think.

With the change in temperature / pressure / winds in this area - I've been doing much 'tuning' on the stove the past few weeks ( sometimes by as much as (100) RPM ) on the Combustion Blower speed at a given feed rate / trimming pellet feed rate up/down as needed, to maintain keeping the burn pot clean.

I don't doubt you have noticed a change in flame after doing all that insulation work - you must be super happy about the 1st floor staying warmer there. I'm waiting until Spring to complete my "Expansion Foam Fiesta" on the Sills downstairs. 2 down, 2 to go.. With Beer.

Since it's a 'major' change, it might be worth it to hook up a Magnahelic pressure gauge and test / observe, just to rule out (or identify) an general airflow issue through the stove(s). * I would.

Ok, back to lurking here.

 

Rob, first of all let me say thanks a lot for taking the time to think this out and write it all up!!! I always appreciate your responses, they are always about as complete and helpful as a person can be!


Now, I'm not going to hit on everything you said - but let me try to tackle the ones that I think are applicable to these stoves. Unless stated otherwise, everything I'm going to say below relates to the P68.

I'm going to rule out the air flow issue, specifically due to burn pot cleanliness, because I keep on that and take care of it regularly. Let's just say I'm crazy OCD about it, and leave it at that. The only thing burn pot related I really haven't done in a while is to remove the igniter cradle and igniter and give them a good blast to make sure they are completely ash free. That is on my list of things to try.

No OAK obstruction involved here because it happens even with no OAK attached. Having said that, the flame dance does get much more pronounced with the OAK attached, so there could be an air / oxygen flow issue specific to the OAK which I will tackle later if necessary.

Your comment about the comb fan being tired really hits home. I don't know for sure, but it has occurred to me more than once that the fan could be on it's way out. It was replaced I want to say in early 2013 so it's got a few years on it now. I'm not planning to buy and install a new one just to see if it changes the flame behavior, however when the time comes to do the comb fan replacement - if it does change the flame behavior, I will come back and update this thread for sure.

One other thing I thought of is related to the air-inlet and the flapper. The flapper moves freely, it's not bound up in any way so no issues there. It does "sway" continuously, meaning it's pretty much always moving as if the air flow conditions are ever changing. I do think this is normal. I will compare on the P43 to be sure they are both doing it, but one thing I have always wondered is about the area beyond the flapper. Without removing the flapper, it's nearly impossible to see and get to, but it has dawned on me - what if something ever got in there and got stuck? Accumulated dust over many years, pet fur, anything really. It doesn't seem likely that something could get in there and only show itself in this kind of way. In other words, I think is that were the issue, I would be seeing more weird behaviors, and probably having outright issues with the stove. At some point, I will try to get in there with some compressed air and see if I can get a blast or two past the flapper and see if anything unexpected comes out the air wash holes or burn pot chamber.

I did do the magnahelic test on both stoves, before and after the OAKs were installed because I wanted to see what affect the OAK would have on them. On the P43, the low draft reading went from -.45 to -.55, presumably because the inbound air flow is more restricted than it used to be. It's a 2" OAK pipe, connected to a 3" air inlet. On the P68, the draft reading stayed exactly the same as it was, which is also -.55.

One other thing I've noticed this season on the P68 (and I don't think it's related to this). The inner seams of the hopper are sealed with silicone, it came that way from the factory. That silicon is 10 yrs old now, and starting to break down and peel off. I don't believe it has gotten to the point of affecting the air / vacuum seal of the hopper, but at some point - before next burn season starts, I will re-silicon those seams so they are like new again.

More to come as this investigation progresses.

 

Please bear with me, never claimed to be the brightest bulb on the tree, but I can't recall if you mentioned if this occurs in both room and stove temp settings. I run just on room temp. Never see the hula flame you talked about. I call it a hula flame, like the hula dance, it is a lazy flame sliding from one side to another. The other flame is like a serpent's tongue. My flame is like the serpent's tongue. However I run on the room temp stat. It will come on, burn hot then die down. On and on, but the temp in the room is consistent. It just burns more or fewer pellets. I seldom get any speed bumps (clinker formation) in the burn pot. My last two tons without carbon build up were MWP.

 

You're welcome for the suggestions TT, anytime for a FHC friend.

I'd give it a clean, and hookup a short piece of intake pipe -> and route a few feet away from the stove inside, to rule out the room convection air blowers may be affecting Intake air volume (or airflow), and test.

* But I agree: if the flapper is moving freely / seems normal, why is it suddenly causing an issue now.. It's a good observation though - something to keep in mind.

Stove here is very sensitive to wood pellet dust/flour/fines at the bottom of the (drop tube) auger feed. We empty hopper / fully vac. about every ton. * If we don't, and dust builds up @ the bottom of the auger, pellet feed gets "wonky" / inconsistent w/ all that dust trying to push pellets up the auger tube.

You may want to consider giving the Hopper & Fines Box a super good cleaning, if not part of the usual service.. From reading how you care for your stoves, I suspect you've done this already.

Stove here likes the new 1,500w Cyberpower UPS units, but was not as happy w/ the 1,000w unit originally purchased.

If running the stove(s) direct from UPS power, I'd try removing the UPS, plugging into a separate surge-protector only & testing, to eliminate a -low power- issue affecting the electronics, or stove motor(s) from the UPS unit.

If no UPS, I'd do a basic voltage check w/ a multimeter / DVOM, just to confirm expected line voltage, in any case. Couldn't hurt.

Was thinking about the above on the ride back after returning Emily back to UNH today - just some thoughts of things I'd also check, if here.

With Beer.

 

Can you remove the flapper?

 

I questioned if my comb blower was failing slowing down earlier this season but was told that they usually don't slow down, they just fail completely. Don't know if this helps or not.

I don't think this is an issue caused by TT's setup as I and other Harmon owners have experienced the same thing.

 

You can also tach the combustion blower while its going on to see if there is a significant change in speed

 

That works for me

 

Good luck finding "a cause" your Harman's are always screwing with the feed and blowers to match up pellets and combustion air. You also have some issues with improperly sized OAKs.

 

I've got 3" flex on my stoves - slips around the outside of the air intake and use a ring clamp to keep it there.

I have had an obstruction in the air intake itself before - a small piece of cellophane (glad it didn't make its way to the hot part of the stove). It was just past the flapper so not obvious at a quick look.