Harman accentra draft setting issue

[3650]

I tried to adjust the draft per the manual. I hooked up my manometer to the port in test mode. It reads -.058 on high combustion fan and -.046 on low.

The manual says to turn the adjustment counter clockwise to slow it. The range on low is -.030 to -.035.

The issue is there is no change when I turn it either way. Anyone have any idea why there is no reaction?

Thanks

 

[Ssyko]

Is the port clear? Im not up on harman but maybe it doesn’t allow adjustments in test mode only in run mode

 

[3650]

It is clear. There is a set screw that is removed to access it. The manual shows and explains the process clearly. It’s pretty simple.

Put the Mano tube in port

Turn stove to test mode. It runs on high for two minutes. Record this reading.

It then goes into low. Record this reading after 15 to 30 seconds.

Then adjust the small plastic screw that is in a recessed hole on the controller. It’s clearly visible.

Unfortunately I’m seeing no change on the Mano when I adjust. This makes me think there is a problem somewhere. Controller or exhaust blower.

It’s running high. Which isn’t really a problem. It’s -.046 on low and the spec is -.030 to -.035. So not too much of a difference but not the sweet spot. Fortunately it’s not running low. That would be an issue.

I’ll clean out the chimney and see what I get. I cleaned it last spring but maybe something got in there over the summer. Mud dobbers might have been in there.

 

[Ssyko]

well then it may be the adjustable potentiometer is dirty. some contackt cleaner or deoxit may help. im sure you know to unplug stove when doing this

 

[3650]

well then it may be the adjustable potentiometer is dirty. some contackt cleaner or deoxit may help. im sure you know to unplug stove when doing this

No I didn’t know. Thanks for the tip. I’ll get some and try that too.

 

[SciGuy]

I tried to adjust the draft per the manual. I hooked up my manometer to the port in test mode. It reads -.058 on high combustion fan and -.046 on low.

The manual says to turn the adjustment counter clockwise to slow it. The range on low is -.030 to -.035.

The issue is there is no change when I turn it either way. Anyone have any idea why there is no reaction?

Thanks

Perhaps my memory is faulty or you're working with different units of measure but IIRC you're off by an order of magnitude on the appropriate vacuum reading. My magnehelic gauge reads on the order of .40" of water column on an Accentra at low combustion blower speed. There seems to be a bit of a lag in change in vacuum when I adjust the trim screw. A 1/4 turn should affect things.

Hugh

 

[Golfeur]

I have a harman p68 and I too have adjusted the draft and a -.030 -.035 I try it for a week and the stove gets dirty so I readjust the minimum to -.042 -. 045 and the combustion is beautiful and the stove does not clog.
a -.o30 -.035 the flame had no vigor and was orange

 

[Golfeur]

I'm sorry I don't remember the value of the manometer but it's the same as in the manual -.042 -.045 or -.42 -.45

 

[SciGuy]

I'm sorry I don't remember the value of the manometer but it's the same as in the manual -.042 -.045 or -.42 -.45

It's definitely on the order of .4 rather than .04 which would provide only the tiniest wisp of a draft.

Hugh

 

[Golfeur]

You are definitely right