Harman P68 Slow Startup

Could it be a flat spot on the rotary switch on the feed rate and/or temperature setting? I'm just throwing possibilities out there. The DDM would be really helpful right now.

 

I run the stove on feed rate 3.5 - 4. Like LW said though, the feed rate setting doesn't affect the startup feed sequence. Thanks to both you and will711 for the startup time info on your stoves, it just further proves that there really is something going on here and it's not my imagination. I'm still doing testing with different pellets and will report back in the next couple days.

Tell me about it, really wish I owned one!

 

My far away Harman dealer was willing to lend me one awhile back, maybe you can ask yours without the service call that is

 

I still think it's a lack of fuel. The pellets should be overflowing into the ash pan in that amount of time.

 

I would call and ask, worse they can say is 'No'..

ttdberg, it looks like the DDM is available on Amazon, costs a lot of coin though.

Silly question: as a sanity check, have you verified the OAK is intact and clear of debris or other obstruction? No changes there?

 

well, after a bit, the feeder stops feeding to allow the igniter to ignite the pellets.....if it doesn't ignite, then it feeds more.....this can often result in larger amounts of pellets in the pot....after like 36 minutes, the stove gives up, stops feeding and you get the error on the status light. Of course, this doesn't mean OP might not have a gummy stove (do you have a bypass tube on this one? don't recall the age).....I think I said this above, but gummy stoves can cause blockages that inhibit the flow of pellets.....so hard to fix these things without seeing them!

How much pellets is in the pot prior to ignition? Is the pot full (almost overflowing, or overflowing)? 1/2 full? 1/4 full? 3/4 full?

The OP has been running the stove and now sees this aberration in ignition, and that makes me think something isn't up to snuff in his machine.

 

My thoughts still go back to a weak ignitor. Can they be tested like rod-type ignitors by measuring the resistance?

 

This is my current theory as well. I really think there's just not enough fuel making it to the pot during the feed sequence. I don't know why though...yet.

I saw the DDM on Amazon. It's a bit cheaper now than last time I looked. I don't have an OAK. I know, SHAME on me! It's one of the longest works of progress I have ever done. Just not yet. No obstructions on the air intake though, thanks for the thought.

This stove is a 2008. No bypass tube, in fact I had only ever heard of that issue affecting accentras. How do I tell if it's affecting me? I'm attaching a picture from tonight's startup. This is what the pot looks like after the initial 4 minute feed ends. This is typical. It was not enough to get flame, and barely reached the first row of burn pot holes (this pot only has 5 rows). I did not see flame until the tail end of 8 bursts of 15s on / 15s off. That was at 11m 15s. The dist blower came on at 16m. On the rare occasion that fire does start at this point, it typically just smolders for while until the well into second long feed sequence. For what it's worth, I got behind the stove and timed the auger revolution. 1 full turn every 8 seconds.

 

maybe I am missing it, but where are your fire bricks? Cant quite tell in the pic if there are any or not.

IMHO there aren't enough pellets in the burnpot for proper ignition. As for rpm's, there are two P68 feeder versions....originally they were a 4 rpm feeder, then went to 6 rpm...oddly, yours is turning faster than that. Weird.

I am assuming this amount of pellets is not much, even for you historically, right? If this is less than what youre used to from previous years, you need to figure out why not enough pellets are being delivered to the burnpot.
In TEST mode, is your feeder light a solid ON, for does it seem to dim or flicker? Watch it for the full one minute high draft sequence....see if test mode delivers more pellets. Something could be messing with your vacuum, which would in turn cause your vac switch to kill the power to your feeder. Only way to catch this is to hook up a draft meter, watch the readings, see where they are, and if they aren't fairly consistent.
Is the feeder fines cover on and tight? Check out the gasket on the cover too, for the fun of it.
The only way you'd tell if you had stuff, like gummy stove stuff, in your feeder is to pull the auger and look up into the area under the slide plate...is the slide plate clean, especially the underside? Do you have any discoloration at the bottom of your bin, and maybe a slightly smoky smell? Gummy units weren't just the Accentra.
Cant stress enough how good it would be for a draft reading here. Your vac switch might be messed up (very unlikely), your comb fan might be on its way out, the circuit board might be done as well.

 

Never seen a weakening igniter. Seen plenty of bad ones. Igniters tend to be good (working), or dead. Now they can get dirty and not work right, but I am sure the OP is on that. Yes,,,they can be tested...should have 42-50 ohms of resistance across the leads.

 

Just wanted to say it's very cool of you to be helping ttdberg out LousyWeather - props for that.

 

eh, I figure you guys are gonna help me some day in your areas of expertise...paying it forward.

 

Weak ignitor versus a different ohm'd ignitor just like different glow plugs on a diesel engine. Throwing bits/pieces of info out trying to get to the bottom of this issue. It does look short of pellets for initial ignition IMO.

 

Well, I personally have had an ignitor that went "half bad"....the rod type can have 1/2 stop working, as I did. It still lit the pellets, but took a LONG time (7-8 minutes). When I took the ignitor out & connected to 120 v, only the last 1" got hot. New ignitor lit the stove in less than 2 minutes.

 

TT, my P61 has pellets up to the 3rd row, and in some places, the 2nd row of pellets after the initial feed of pellets. You don't have anywhere near enough to light the stove, they're not even up to the igniter yet.

 

I think you can just see the bottom of them at the very top of the pic.

 

Yes, agreed! thank you so much to LW and everyone that has replied with advice! We will get to the bottom of this!

This is what I have been thinking, thank you for confirming it!

Yes, the firebricks can hardly be seen, due to the angle I took the picture at. I held the camera above the burn pot and shot the pic almost straight down so you guys could see the burn pot holes in relation to where the pellets were. The firebricks are in there, they just barely make it into the picture.

 

When in test mode, the feed light is solid on. There is nothing stopping it or weakening it. I have taken the fines cover off a few times over the course of this week and each time verified it's securely on when done. I don't think that's it. There is no discoloration at the hopper bottom, it is clean and clear. The feed hole is clear too. With the slide plate out, I have pushed my finders as far in as they will go, and there are no obstructions or anything the slightest bit sticky or gummy. Also worth noting if the stove is on and I put my hand down there, there is a very strong draw of air being sucked through there, which I believe to be normal and good.

I turned on the P43 tonight. I can tell you just from listening, when the P43 auger turns, and moves the slide plate, there sounds like a HECK of a lot more pellets tinkling into the hopper chute than what I hear when the P68 auger turns. I really do not want to pull this auger out. Can you tell me if there is a gasket involved or not?

Tomorrow I am going to shut it down and once again open the fines box and see if there is any way to see or identify if there is anything going on in there. It really seems to me like the slide plate mechanism is somehow involved in this, perhaps something in the fines box is restricting movement. If I don't find anything there, then the only other way I know of to get further into the investigation is to pull the auger.

 

Thank you Jay, I thought maybe the auger was not turning quickly enough but I clocked it tonight and it's turning one full revolution every 8 seconds. That's actually "faster" than it should be turning. Maybe a hint there? If so, what is it a hint of!