Harman P68 Slow Startup

no, I haven't. To check it, just follow the bearing (item 3.2) as it travels inside the pusher arm weldment (3.9). It should be fairly centered and in contact with the "C" of the pusher arm. I guess if it travelled outside of the "C", it might not throw correctly, but I have never seen that. The diagram appears to be a Ultralight feeder mechanism as well....cant quote when that came out, but prior it was larger. The diagram though does give the user which serial number to look for to determine if theirs is a PRE or POST unit. Kinda important when ordering parts.
In my experience, the gears within the gearbox usually lose teeth before anything happens to the pusher arm weldment. The nylon gear in the feeder I feel is the weak link in this case.

 

well, one bearing is actually outside the fines box, while the other is inside. Dry lube is better anyhow. Except tears.....tears work well as lube, from the OP's frustration!

 

Hey LW & JT & all,

I imagine ttdberg is tearing into the P68 and 'getting it done',

Thanks to the help you guys are giving here.

(ttdberg, a picture is worth a thousand words.. feeder assembly pics for LW and JT, please?)

 

OK, last night I disconnected power, emptied the hopper, took the back shield off, and also the control panel so I could see directly into the fines box. Not much to see in there, no foreign objects or obstructions. I took the slide plate out again, and cleaned out the area beneath where is slides. There was some fines in there, but there have been every time I take it out, I think this is normal. Vacuumed everything out. I noticed the arm that moves the plate had a little friction moving back and forth. Not terrible, but it definitely wasn't moving as freely as I thought it should. So I put a couple drops of 3-in-1 oil where the pin meets the brass rings. That made the pin move *much* more freely, it was quite a difference. Put everything back together, ensured the slide plate moved very easily, which it did, and started it up. The initial feed put more pellets in the pot than I had been seeing. Flame at 5m 10s and distribution blower at 8m 50s. This is promising. Too soon to tell, but it could have been the pin needing to be lubricated all this time? I also observed as the stove ran last night and I am getting a noticeably bigger flame than I was. I will know more after I light it a few more times. Of note, the wheel on the auger arm does not stay in contact with the slide plate arm for the entire time. It touches the long side of the arm long enough to push it up, then it loses contact, and then briefly "hits" the short side, pushing it back. I believe the brief loss of contact is normal, as the P43 does this as well. I also noticed that the spot on the short side of the arm where the wheel "hits" it appears worn flat. On the P43, that same spot is not worn, and the wheel remains in contact with that end of the arm for a longer duration than it does on the P68. Not clear yet if these observations mean anything useful. More to come.

LW, when the Harman man was here to replace the combustion fan motor a few years back, he pulled the deflector plate out of the fines box, indicating that was Harman's recommendation these days. The P43 came new without one. What was the purpose of that deflector plate in the first place, just curious? One other quick observation. If I look inside the fines box on the P68 I can see the auger. On the P43, when I look in the fines box, the auger can't be seen as easily because there is a metal housing around it. Design change, I guess.

 

deflector plate in/out, doesn't matter. Kept pellets from rolling in there, not many did roll in anyhow.....

hey, maybe you fixed it lubricating the pillow block bearings.....but that's pretty odd, really. They aren't really made to lubricate, but if it works for you, great! Any chance the retainer bolts holding the bearing enclosures might be loose or offset, throwing the shaft into a bind?

As for design change.....are the slide plates the same width in the p43 and the p68? If not, you're p43 is an ultralight, while your p68 isn't.

For what its worth, you can fun the feeder with the feeder cover off, you just have to pigtail the feed motor.....then you can watch the thing run. What you're really looking for is the stroke where the slide plate opens....which is the "long" side of the "C"...or the upper fork of that arm....the slide plate should come back almost to where the feeder cover is, but not quite....I've never actually measured it...but if its staying way forward, you might have an issue.

 

No bending or twisting Jay. The wheel is perfectly centered with the arm. That part 3.9 is the one where all of my focus is though. It's the part I have been referring to in the past couple posts. If lubricating the pin hasn't solved this, then the only other thing I can think of is the short end of that arm has literally become worn to the point where it has lost it's full effective movement. Doesn't seem like a wear and tear kind of part to me, but the very tip of the short end has a flat spot on it, which seems like wear to me. This may be a red herring though, because I think LW said he hasn't seen this part needing replacement before. I will give it a few days with the oil I dropped in last night, and see if the results remain positive before I pursue anything else.

Thank you guys, seriously - all of you, for sticking with me on this.

Edit: The good news is, if I do need to replace that arm, my Harman guy sells it for $35.

 

Just make sure you get the right arm! See my above schematic. Check out your serial number. Yours APPEARS to be a UL unit, but cant be sure from the pic.

 

Got it, will do!

 

I'd go with your gut feeling on this - if you think it's wear, and that is the side that kicks the feed plate back / the side you've been having the issue with, I would order & provision for part replacement.

Nice pics!

 

The P68 serial is post 008280309 so the diagram Jay posted is accurate for this machine. Same as #3 feeder assembly in LW's diagram.

 

Any headway ttdberg ?

 

I don't think the oil fully resolved the issue, so I ordered a new pusher arm. They called and said it came in, so I will go pick it up on Wed and post some results after I get it installed.

 

we're waiting!!!!!

 

Hello pellet pals. OK, good news. This problem is officially solved. I went to see the Harman man this morning and picked up the new pusher arm. Installed it this afternoon. At the end of the first feed cycle, the pellets were all the way up to the 4th line of burn pot holes. Flame at 4m dist blower at 5m. I have not seen a persistent flame this tall in this stove since I can remember! I set the feed rate at 3 before startup and the temp gauge on the side of the stove is reading 550 degrees. CRIPES! This is burning Vermonts, BTW.

Images attached for your viewing pleasure. Take a look at how the tip of the old pusher arm was worn down. That little bit of wear made all the difference in the world. It is not clear to me how the old arm became worn. Three different Harman dealers told me they have never seen this part need to be replaced before. I can only think of two theories. The metal was "bad" to begin with, or the arm became semi-frozen / seized in place at some point, resisting being pushed by the wheel? I'm going to keep an eye on it to see if a wear spot develops on the new one.

HUGE THANK YOU to all who listened and supported me and helped troubleshoot this along the way. Seriously, I really appreciate it a LOT!

Happy Thanksgiving everyone, and stay warm!

 

SOOO what Flavor are you drinking to celebrate

 

Shipyard Pumpkin Head at the moment!