Harman advance low draft adjustment

hey all. Yet another question on low draft adjustment. I installed this 2004 advance in my basement 2 yrs ago. It does a good job heating 1,100 sqft finished space.ive since installed a p68 upstairs and that thing is a beast. I have a Dwyer draft meter and a harman ddm as you can see in the pics. On the p68 I was able to get it dialed in good and was able to adjust the draft down and it's set at .4 for low draft. My issue is with the harman advance in the basement. I have high draft reading of.9 and low draft reading of .6 and that is with the adjustment screw adjusted all the way.(shows-10 on ddm) I have a low brisk fire with Pellets's popping out of the pot. It's been like this from day one I guess but I'm looking in to it more now after seeing how the p68 burns so much better. I've tried putting tape over the outside air but that hasn't helped much at all. Stove is squeaky clean as is the vent. Selkirk direct temp vented out basement window. Has new door gasket. How can I get it down to a lower draft. I've contemplated removing the vent and installing basic 3" Simpson venting most of which I have lying around. Also considered swapping out the control board for an updated one. The newer boards have more adjustment in them so I'm thinking that is the way to go. I also have one of those boards on hand. Is my thinking correct on this or is there something else I should pursue.voltage at outlet reads 126.5v

 

Hi Corkman
I have a 2004 Harman advance with the new circuit board and was disappointed when I got the low draft down within the Harman spec. So I put it back to the default setting.
Do you have the new fluted burn pot?
I do.
I just got the crossover air update kit but did not install it yet however that could make a difference.
Do you have that "Gummy Fix" air tube kit?
See my thread
http://firewoodhoardersclub.com/forums/conversations/a-little-frustrated.8134/#message-121507

 

Give you some info.(I do repair stoves intermittently).A lot of your heat is going up the chimney.Some background,I have an accentra upstairs,about 6' vertical then out,4" as I am at 6500 ft.Pots when bad last year,so got the new board when they were on sale(also repaired old one,I like spares).Stove was always a bit dirty,glass got dirty faster than I thought it should.With new board,runs cleaner at low burn,and has some other different burning characteristics,but none bad,also had more adjustment for blower trim.Well,people wanted me to try the high altitude impeller last year,as reccomended by harman,never got around to it.Put it in a while back,have burned about 15 bags,glass is almost spotless,can tell not as much heat.With that much stopping and starting last 2 months,glass should be dirty.Gauge starts at 5,drops to 2.8 on rip roaring burn.Old impeller would be about 1.7.full burn.Personally I think it is too much,lots of other stoves run .13-.24.Some ussc units were so high(.8) very little stove heat was coming out.The fix was block off over 1/2 of the air inlet.Never tried it for long on my harman,flame seemed to vary too much. As I am a cheapskate and hate to waste pellets,I have ordered a new high altitude impeller(same impeller is stock on your Advance,the double blade impeller) and am going to experiment with cutting off some of the blades.Some people(and techs) think it is great to run soooo clean,but I hate wasting pellets.Now you can draw some more conclusions,but for a quick easy test,as you are low in altitude,buy a single blade impeller and throw on there,easy to tell with your gauge.Cheers

 

Hi don I did crossover tube right when I bought it. Not sure about the pot but here's a pic. I did put a new double fan blade in when I bought it but can't remember if it had a double or single when I bought it. That's a cheap test so maybe I'll pick up a single blade and pop it in

 

double is stock on them

 

Hi Corkman
Harman recommends the double paddle blade for that stove, my dealer friend said they originally came with the single paddle years ago but they changed to the double paddle. However it looks like some of your double paddles are separating and that is why Harman finally went to rivets on every pedal. So you may want to get a new double paddle.
Good work on the crossover air kit, I have a lot of black buildup of carbon in the burn pot and I am hoping the air kit will reduce it.
I have the Selkirk DT like you have and I would never change that, it works well.
The new flame guide for the new fluted burn pot has two notches in the back so you may not have that.
The 2 notches bring up air from under the burn pot to push the flame away from the back brick panel and it works well.

 

I bought the paddle blade new 2 years ago at harman dealer. I don't see any separations. Can you post a pic of the new pot. I know for sure it's the old style flame guide and it does not have the notches you refer to. I've seen that in a number of your other posts

 

Here is the new burn pot
Harman P43, XXV, Advance & Accentra Insert Burn Pot Weldment - 1-10-00675

Here is my thread with my pics of the new vs old pot.
1999 Harman Advance - Flame Lapping brick Backing creating Black Burn Spot! | Firewood Hoarders Club

 

Corkster-
Dont lose too much sleep on this draft....sometimes there's not much you can do. Yea, you can stick a new board in which is more adjustable, but anything lower than say 12 volts can cause other issues.....some folks dial them right down, and then, when the stove gets dirty, it REALLY drops...often past the vac switch opening point, which is somewhere between -.15 and -.17 on your meter......then the thing wont feed, shuts down, etc. So, a bit higher draft is better than too low. Ive seen units that even dialed all the way down are high.
I dont reccommend things like restricting the intake, etc, as your draft characteristics will change given alot of factors such as cleanliness, weather, etc.
Its not the burn pot either...don't bother changing that.
And yea, the most modern Advances are the 5" double bladed impeller......2004? Not sure.

Heres a little test for you though......restrict your intake, see what happens with draft. Then, go ahead and restrict your exhaust and see what happens. I bet alot of folks will be surprised at the outcome.

Good luck!

 

Well lousy and I have disagreed before,makes life fun!However,IMHO in your case,lots of heat is being wasted up the flue.And Don's memory is correct,the older ones had a single bladed impeller,double was recommended above 7000 ft(found old manual) much like older accentras.Slap a single on there and try it,and keep us posted.

 

actually, to be accurate, once upon a time they had a single high altitude impeller available......now THATS a trip down memory lane!

 

Hi guys and ty for your input. Trill be the weekend before I get to play around a bit with the stove but I will be sure to post update

 

Well I still believe,from the readings I have seen on other stoves,you are wasting heat.Kind of like running an engine very rich to make it run cooler.Or running your tires overinflated for better fuel mileage,but the tires wear out faster.(I could go on) I like balance.As you are a tinkerer,and knowledgeable,I will be watching for your results.Also,been thinking,a pwm motor speed controller inline with the combustion fan would do the same thing as a smaller/less paddles impeller,and would not affect the harman controller,as the exhaust probe and programmer would make it a same factor as if a smaller impeller was installed,may order some parts and make one.Keep us posted please.

 

So I made it to my harman dealer today and picked up a single blade impeller and got it installed. Not a huge difference in my draft numbers to be honest. The original high draft was .9 and now I'm at .8 and low draft was .6 and it's just a tad lower with the new impeller at .58

 

Great Info! Very interesting. It seems the double paddle just keeps the ash from building up behind the blades so it goes better longer.

 

After reading what lowsyweather posted above I again ran stove in test mode and started to restrict the outside air to the stove but this caused the draft gauge to start climbing even higher. After that I figured I would try to restrict ghe exhaust. Wasn't quite sure how to approach this but this is what I came up with. I just used some metal tape and closed off half of the exhaust path. Ran it in test mode and high draft was .6 and low .5 All of this was done with the low draft already adjusted down to the max which on this board is -10v.

 

my point is basically that when the intake is restricted, draft increases, while when the exhaust is restricted, it goes down......VERY important fact to consider when diagnosing stove issues....where is the blockage......also very important in understanding why a draft reading can be so important....bees in the intake? draft increases.....bird in the exhaust? draft drops

 

Ty lousy weather. I decided to fire it up with the new impeller in there. While the draft numbers didn't change all that much the fire sure did. Much much better looking fire and huge increase in the heat. Prior to this I was having a difficult time even satisfying the ESP cause the fire was so low in the pot and decent sized pellets bring ejected from the pot. An hour in and I see a noticeable all around improvement. ESP is happy too........ Why does the draft number drop do much when the stove is actually running. Draft reading in test mode on high was .8 and now with the stove running on high it reads .43

 

A few pics

 

I'm trying to jog my memory on what I did when I 1st got the stove. I honestly don't remember if the impeller I removed was single or double but I do remember doing lots of reading on here about the advance and that it uses the double and that's what I put in. I'm wondering now if the stove is older than 2004 and maybe it was a single that I took out. There'd no date in it just a serial #012596