Harman P43 feed rate issue.

[ajbass]

Hi, still having issues getting max burn out of stove. Let me start by saying that the stove is clean, door gaskets replaced, new esp, new auger motor, tried my spare control board, and have removed auger/slide plate/etc and inspected and cleaned. 1 also swapped temp sensor with my second stove. I also confirmed dip switch settings 1-3 on, off, off +21secs.

Using the same pellets on my two P43's, one stove feed rate on a little past 3 will fill burn pot and burn pellets to the edge on high heat demand. 2nd stove with feed rate at 6 with high heat demand, I can't even get close to the edge of burn pot. The ash line is low in the burn pot and stove (hot air output is 100 degrees less) is putting out far less heat.

Question: Has anyone changed the dip switch settings to get a longer auger feed cycle (ex: 1-3 on, off, on +43 secs)? I'm thinking with a longer cycle, I could always turn down my feed rate to control?

My 2nd stove is in basement and only use when I plan on working in the basement. With the low heat output, it takes an extended period to warm up. Once it does warm I can maintain the temp.

 

[railfanron]

My guess is you have to much draft on the second stove. How high the pellets get and how much heat output in the convection stream is determined (if all parameters are the same) by the amount of airflow in the exhaust. I would get a manometer and check to see if it's within factory specs. I think the exhaust flow is probably too high.
Ron

 

[ajbass]

I did purchase 1 and will try to pick up a fitting tomorrow. Can I check from the hose to the low draft switch? That is the difference between stoves. Main stove is a straight 3' shot through wall. Basement has 1 tee, 1 90 and approx 2' vertical and 5' on incline. I did use the 4" duravent. My last resort will be to swap stoves.

 

[Lake Girl]

Do you have an OAK on the basement install? Basements are far more air tight so may be starving for air...

 

[ajbass]

I just connected my Dwyer gauge to to low draft switch. Ran stove in test mode and high draft was .7 and when low draft kicked in it was .4! Do I have to get an adapter and test at the draft port?
I have tried running with cellar door open and the intake flapper is in full open position when stove is running.
The thing is, when I have the stove running, and auger cam is in idle position. I open and close slide plate (or add handful of pellets to pot), which allows extra pellets to fall in chute to auger. a short time later the burn pot will fill and stove output increases dramatically.

No outside air, room intake.

 

[Lake Girl]

Sorry I missed your response on Sunday ... This should help you
https://www.hearth.com/talk/attachments/pellet-stove-service-training-3-pdf.92157/

 

[ajbass]

I did hook up the gauge with a tee to the low draft switch. In test mode I get high .7 and low .32! My good stove gets .7 high and .4 low. I left hooked up while running the stove and it's only stays on the high reading while firing up. Once running the it's at .32!

I started to see if the 6 rpm auger motor (may fabricate bracket) would fit. If I force extra pellets in the auger, the stove runs great. It just doesn't feed enough pellets to burn pot?

 

[alternativeheat]

I'm wondering if you got the right RPM motor with that auger motor you replaced.

On another note, the basement stove may not be calling for the heat the same as the upstairs stove. I know that my P61 at times may have quite a full burn pot and at other times quite a low burn pot, depending entirely on demand and with the exact same pellets and feed rate 4 . That's in Room temp mode. If you run the stoves both in Stove Temp mode , say auto for now and the same settings , what happens then ? And at that, the venting differences may effect the ESP behavior, in fact probably will..

 

[ajbass]

I don't run the basement often, so when I fire it up the temp will be 50 degrees, so I'm calling for high heat. With feed rate at 6, I should be pushing pellets over the edge. It's like it goes into a low burn mode while calling for full heat?

The motor is the 4 rpm motor. My upstairs stove auger was noisy (feeding good), so I replaced it. I did try that one in basement stove with no change. I have also since replaced with new 4 rpm.

 

[alternativeheat]

Not necessarily, these Harman feeds are funny . If the ESP gets satisfied and stays that way the feed is going to cut right back, regardless of your feed setting. I think it's 500 deg exhaust temp at full tilt and 350 deg in the mid ranges and a bunch of numbers in between ( assuming the ESP is calibrating correctly).. So draft can effect early cut back ( probably what railfanron was suggesting as well). I don't know, I'm just throwing it out there. It's gonna be interesting to know what nails this down !

I have 4" venting and I doubt my P61 could ever push pellets off the burn pot. I know I did a 1" ash line at feed rate 5.25 or so when we first got the stove, I don't think 6 would gain me that inch and what ever else to get pellets falling off the burn pot.

 

[TonyVideo]

Swap the ESP probes as a test. Maybe one is regeristing hotter than it actually is throttling the stove.

Sent from my SM-G930V using Tapatalk

 

[ajbass]

I also went as far as getting the P68 auger motor with the 6 rpm feed and had no change. The probe has to be saying it reached temp and going to slow burn. The draft is still measuring just over .60 during startup and shutdown. Once stove is burning it drops down to .32. My good stove is .7 s/u and .4 in burn mode. I had bought a couple of spare probes (fairly cheap) on Ebay and will try another.

Thanks everyone for suggestions....

 

[ajbass]

Ok, I have two (red wire) original ESP's and 1 new. Measured resistance 1, 1066, 2 1065 and 3rd 1062. Has anyone ever measured theirs? I did ask Harman and this was their response:

Thank you for your inquiry, There is no test really because most people do not own the necessary equipment to test the ohms on the ESP, i can tell you at 60 degrees the ohms should be 728.7. To get more information your dealer will be your best resource. to find a local dealer near you click the link (broken link removed to http://www.harmanstoves.com/Service-Locator.aspx)
Thanks
Austen

 

[Lake Girl]

Not very forthcoming on information so not very helpful. Have you asked the dealer if he knows?

 

[Lake Girl]

Thought of this chart but they don't include ESP values...
https://www.hearth.com/talk/threads...cret-so-guard-this-info-with-your-life.94568/

 

[Lake Girl]

dhall response on this thread ... https://www.hearth.com/talk/threads/harman-esp-test.106847/