Harman draft adjustment not functioning

[pianoman8t8]

Hi all,
Recently picked up a used XXV pellet stove. It runs fine, but I do have it being vented to a roughly 25ft vertical insulated liner. In checking and trying to set draft via Dwyer gage, and trying both 60 second and 2 minute wait intervals (hard copy manual differs on this compared to online manual), the combustion motor does not fluctuate between a LOW and HIGH run setting. Just a constant state of about 0.7inwc. The draft adjust makes no change going from full CW to full CCW. Anyone else see this before and what was the fix? I haven't been able to find any info on this including from dealers. The general consensus had been "if it runs leave it alone". I don't like that answer, an adjuster should in fact adjust something... Thanks.

 

[pianoman8t8]

To clarify, the distribution blower DOES alternate between HIGH and LOW, but the combustion blower does not.

 

[pianoman8t8]

Also another interesting note, it runs at about 0.45inwc while running. But, in test mode, it's much higher and never comes down. The draft adjust also makes no change in the 0.45inwc while running either.

 

[Dataman]

I just set my Harmon XXV to room temp and leave it. What setting are you accessing. I know of none on my XXV (Pre TCI). Computer does all the work on it. Exhaust probe gives the reading to the CPU.

 

[Whitenuckler]

Hi all,
Recently picked up a used XXV pellet stove. It runs fine, but I do have it being vented to a roughly 25ft vertical insulated liner. In checking and trying to set draft via Dwyer gage, and trying both 60 second and 2 minute wait intervals (hard copy manual differs on this compared to online manual), the combustion motor does not fluctuate between a LOW and HIGH run setting. Just a constant state of about 0.7inwc. The draft adjust makes no change going from full CW to full CCW. Anyone else see this before and what was the fix? I haven't been able to find any info on this including from dealers. The general consensus had been "if it runs leave it alone". I don't like that answer, an adjuster should in fact adjust something... Thanks.

I have been down this road before less than a year ago when I got my P43. The install manual had all the details on how to measure the vacuum in test mode and set the adjustment POT and it all worked for me. I'm not sure if you have the same control card or instructions. You need to verify what version card you have, and use the proper instructions. 0.7 is great, but too much. Check the vacuum with no power. Maybe you are getting natural draft.

 

[bogieb]

My P-series stove manuals state the following - so, as long as you are at or above the minimum vacuum requirements (while running), you are fine.

If I'm reading correctly, the adjustment is actually for the voltage and should be done while it is NOT running.