New Harman OEM hopper Extension issue! Fix?

Hello
The Harman extension Hopper has been easy to install with it's hopper Lid and 3 swell latches. The old lid can just be flung open and the extension just plunked on and latched up. All done right? Not on the newer stoves with the vacuum switch sensor that is mounted in the bottom of the hopper! The old stoves with the vacuum air tube going into the back of the feeder welderment worked well but did not detect if the hopper was opened to stop the auger from turning like most other stoves. The new sensor in the hopper will now do that and the stove will not run when the hopper lid is opened.
That may be fine and safer however if the hopper extension is installed on one of these stoves, then many times there is too much of an air leak for the stove to run!
So in this case, I removed the hopper extension, and removed the original hopper lid. Then put down a bead of high temp clear silicon and installed the hopper extension with 6 self tapper Stainless Steel screws to make an air tight seal.
Bingo it worked and the stove works as designed!
Anyone have seen this problem?
See pics
Pic 1 - Leaky hopper extension had pellets stuck in between! Also see original hopper lid with piano hinge riveted on.
Pic 2 - Drilling out rivets that hold piano hinge on stove for original hopper lid with a 1/8" titanium drill bit.
Pic 3 - Bead of high temp silicon for air tight seal
Pic 4 - New Stainless Steel self tapping screws to clamp hopper lid down for a good seal.
Pic 5 - wipe off excess silicon after hopper extension is tightened down.

 

When I put the extension on the P43, I also ended up putting a bead of HT Silicone in between as I could actually see light thru places despite the fact the hopper extension has a gasket on it already. Was still able to use the 3 swell latches and didn't have to remove the old lid. However, the stove is older so has the vacuum switch button that needs to be pushed down by the lid to work. I bypassed that using a piece of thin metal to hold it in place. However, I'm the only one that ever deals with the stove so am not worried about it.

 

I think you are talking about the hopper lid switch. There is an extension kit to bring it up to the hopper lid on top of the extension Hopper.
Hopper lid switch
Harman 48 Inch Hopper Lid Switch - 3-20-232108
Retrofit hopper lid switch kit when adding a hopper extension
Harman Retrofit Hopper Switch Kit for Extension- 1-00-06826

 

I know all about the switch extension, there is one on the P61a that they installed when they brought in the stove. Chose not to spend the $$ for the P43 - the extension itself cost 25% of what I paid for the stove. If I had bought the switch kit, I would have been at 1/3 of the stove price

 

$51 for a push switch and some cable??? YIKES!

 

My 3 Harmans are so old they have no hopper lid switch.

 

I was just counting the retro switch kit at $100. Hmm, doesn't even include that $51 in cables

 

hmmm....seems some confusion in the lid switches.....I am currently not having my Alzheimers' lapse, so, lets see if I can come up with a "damm.....my stove wont feed because the vac switch is faulty" chronology.....
1. Vac line went directly to the air wash conduit.....this would be considered "old school Harman".....(as in, Dane original)
2. Vac line is now connected to the hopper sensor (the little yellow "nipple" thing in the bin, that, even though being of brilliant design, showed itself to clog due to fines, and since noone ever cleaned it, was problematic....when it clogged, stove wouldnt feed, nor light)
3. Vac line plugged into feeder box, with a PLASTIC plunger hopper lid switch, such that if the hopper door was left open, no feed, no ignition...problematic, as sometimes the plastic plunger would break.......note that ANY hopper lid switch was a problem in that if pellets were left on the hopper lid, it could cause the stove not to feed or ignite.
4. PLASTIC plunger changed to a METAL plunger, less prone to breakage
5. Presto-chango! Due to different criterion in the safety world, NO lid switch! Vac line still plumbed into the feeder box (see #3 above).....(this is current)

There may be small interim changes that escape me........
Lately, with the new circuit boards, we can now even diagnose when the vac switch is shutting down the feeder and igniter! This issue is likely the most common issue with techs......"My stove wont light/feed".........noone ever mentions the Status Light error code......but this issue is USUALLY, almost always, a cleaning issue. Sometimes it can be a bad feed motor, even more rarely, a bad vac switch (VERY rare!)......lots of folks working on their own units assume its the feeder, replace that motor, then, the vac switch, replace that, then are at a loss as to why it wont feed or light......didja check the fines weldment/cover? Didja clean your pipe and spark arrestor?

Please note, that if the combustion fan isnt working, it wont feed or light either......check the comb fan first.....possibly the most likely culprit....DRAFT TEST IS IMPORTANT HERE!

 

I can imagine a person can do whatever they want, but technically, I don't believe so. While my understanding of testing is limited, I understand the stove is tested as a system, and that modifying a testing system would probably invalidate the testing. Maybe not enough for an insurance company to deny a death or fire claim, but who knows? Thats why we don't modify them......we repair them as built, since we aren't willing to accept the possible liability of doing otherwise if something were to happen.

 

Smart man.

 

well, its a litigious world be live in, unfortunately. Darwin's Law no longer applies.