Harman XXV Draft Setting

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Hiker05

New Member
Nov 25, 2009
8
Central Sierras, CA
Just a thanks to every one on this forum for all the good info. I installed my XXV the first of October and after 1 1/2 months I felt I wasn't getting the heat output for the amount of pellet usage. After finding your forum I started reading about draft settings (dealer said don't worry about it). I checked the draft and had to turn it the whole way down to get to .40. After resetting it, feed rate had to be reset from 4.5 to 4, blower air temp went from 230 to 260 and pellet use has dropped. This stove is vented through 26 feet of 4" ICC pipe with a 20 foot vertical rise. This may not help everyone because I have a fairly large rise, but the draft setting on a Harman is important. Thanks to all again for the great posts. Note: temps were with Bear Mountain Premium pellets.
 
Curious to know how you measured and set the draft.
 
I used a manometer. Then adjusted with the set screw on the panel. There was a visible difference in flame pattern after adjusting. I think I was sending a lot of heat up the flue.
 
You can also use a magnehelic guage.

IMO,Too much draft is like a lean running engine. You get excessive heat in the exhaust. Yes you want a lean burn, But not to lean. Too lean is as bad as too rich(messes up the stove with black crap).

I adjust my draft for every brand of pellets I burn.

Of coarse always try to stay in the factory set range!

hiker05, Nice post and I wish I could get the Bear Mountain pellets near me. I hear there real good.

jay
 
OK, the adjustment on the panel is for low level burining, correct? Is this the only setting that matters or does it also affect high burning as well?

I'm asking this only because the stove is putting out good heat, but I am ging thru a bag of pellets a day. I do realize that the basement install will use more pellets, but want to make sure efficiency is where is should be.

Should this have been checked at install?
 
I also thought it was for low draft only , but I adjusted it as a test on high fire and it changed the fire pattern. Before the adjustment it was pulling the flames below the burnpot.This is my second Harman and the dealers have never adjusted the draft though I think they are supposed to. My last stove was in a small house with 10' ceilings. this one is a larger cabin with 22' ceilings and 20 ' rise in the flue. I need all the efficiency I can get.
 
Yes, in most cases the setting of the draft will not make much difference. But in your case it is important. Very high vertical will affect the draft whereas most common installations are with straight horizontal or only about 4 ft of vertical pipe. The dealers you are referring to are probably making a blanket statement. Most of the time it does not matter. But sometimes it does and the installers are supposed to check the draft readings and write them in the owner's manual. Harman, unlike other brands does not make it easy to adjust the draft as the end user. Many other brands have an adjustment on the air inlet to help with draft control. That can be both good and bad. Some folks should not be given too much to play with.
 
gbreda said:
OK, the adjustment on the panel is for low level burining, correct? Is this the only setting that matters or does it also affect high burning as well?

I'm asking this only because the stove is putting out good heat, but I am ging thru a bag of pellets a day. I do realize that the basement install will use more pellets, but want to make sure efficiency is where is should be.

Should this have been checked at install?

Gbreda i'm in the same boat i think as you. I am curoius now if my draft setting should be checked for proper efficiency. I'm running a P-68 in my basement as well. My exhuast extend about 5 feet up and then out a basement type of window modified for the stove vent. And as with some brands i try i see that the stove looks like it is running rich (black crap).

Were can i get one of these testing tools from?
 
The draft on a Harman is affected by voltage as well as vent configuration. I feel all dealers should check draft. If you burn 5 tons/year and gain as little as 2% efficiency that saves you 25$ per year. It takes the dealer 10mins to set( I never did it before and it took me 15min). Harmans are set for 120 volts. Voltage can vary between 110 and 130 Volts to be considered acceptable for a utility. If an installer didn't check draft did he check voltage? I doubt it.
 
exactly correct, Hiker....couldnt agreee more....also, an initial draft reading can be VERY important in a diagnostic sense, down the road. New draft reading is alot ,lower than initial reading "a few months ago", and the homeowner cleans the stove "all the time"? Yea, its probably dirty....that'll be $169 dollars please.
 
Hiker05 said:
The draft on a Harman is affected by voltage as well as vent configuration. I feel all dealers should check draft. If you burn 5 tons/year and gain as little as 2% efficiency that saves you 25$ per year. It takes the dealer 10mins to set( I never did it before and it took me 15min). Harmans are set for 120 volts. Voltage can vary between 110 and 130 Volts to be considered acceptable for a utility. If an installer didn't check draft did he check voltage? I doubt it.

Excellent point Hiker, I never considered what the voltage actual is coming out of the outlet. But i can see where a few volts either-way can affect how many RPM's the draft motor actually turns.
 
Hiker05 said:
The draft adjustment screw actually adjusts the draft motor voltage

OK, now it makes sense to me as to why wall voltage is important and how an electrical potentiometer can adjust air draft. I pictured a a variable mechanical gate of some kind, not motor speed.

So is the draft measured and adjusted at high or low burn...or does it matter?
 
gbreda said:
Hiker05 said:
The draft adjustment screw actually adjusts the draft motor voltage

OK, now it makes sense to me as to why wall voltage is important and how an electrical potentiometer can adjust air draft. I pictured a a variable mechanical gate of some kind, not motor speed.

So is the draft measured and adjusted at high or low burn...or does it matter?


It is set in the test mode during the low draft time.
 
My Harman XXV burns great but generates a lot of ash. I have always burned premium pellets and am pretty good at cleaning the unit regularly. The manual says that you should be able to burn up to 1 ton of pellets before you have to empty the ash bin. I empty that thing all the time!! I know the dealer never did a draft test when he installed my Harman XXV two years ago and I thought this might be affecting the efficiency of the burn. I would like to check it myself but am clueless as to what kind of draft meter I need. I did find this link....anybody know which one would be appropriate for the XXV??

http://instrumentation2000.com/dwyermagnehelicdifferentialpressuregauge.aspx

This is my first post. GREAT site. Thanks for all the help.
 
weezy said:
My Harman XXV burns great but generates a lot of ash. I have always burned premium pellets and am pretty good at cleaning the unit regularly. The manual says that you should be able to burn up to 1 ton of pellets before you have to empty the ash bin. I empty that thing all the time!! I know the dealer never did a draft test when he installed my Harman XXV two years ago and I thought this might be affecting the efficiency of the burn. I would like to check it myself but am clueless as to what kind of draft meter I need. I did find this link....anybody know which one would be appropriate for the XXV??

http://instrumentation2000.com/dwyermagnehelicdifferentialpressuregauge.aspx

This is my first post. GREAT site. Thanks for all the help.

0-1.0" water
 
weezy said:
Hiker, I must apologize for my ignorance, but I am guessing that I will probably also need some sort of 'tubing' to hook this gage up to the stove? This link shows a bunch of optional accessories....do I need any of this? Again, your help is much appreciated.

http://www.dwyer-inst.com/Products/Product.cfm?Group_ID=26&Product_ID=1301&sPageName=Options_Access
I purchased this one, comes with everything needed. Paid $9.95 plus shipping

http://cgi.ebay.com/Dwyer-2002C-Mag...emQQptZLH_DefaultDomain_0?hash=item56374026f8
 
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