Harman XXV low/high draft virtually the same...

[lbcynya]

Had the stove for a few weeks. Brand new, mfg in March 2009 (I know). Basement install with OAK. Newer daylight basement with a 4' concrete and with standard framing from the top of the foundation wall to the ceiling. Length of OAK is about 5' and length of exhaust is just under 7' or so. Both exit the side of the house.

Harman center vent kit with 4" pellet pipe to the cap. OAK is 3" PVC. Checked the OAK to insure there were no obstructions.

Got my magnehelic yesterday and gave it a try last night. Have it balanced and zero'd to insure proper readings. Readings taken with a cold stove (ok per manual) on test mode.

With the draft adjustment pot all the way down (ccw) the low draft is reading about .49" and the high draft is about .54" Per the manual, this suggests that my low draft is too high and my high draft is on the low end of the range. What gives? Any comments/suggestions would be appreciated

Edit - Results don't change with the OAK removed...

 

[lbcynya]

Anyone? Sorry for the shameless bump.

 

[shawn7329]

Hi, I have a similiar problem with my XXV and can't seem to get an answer via this blog. Sorry I can not be of help to you. Can I ask what model type you ordered for your Magnehelic draft meter? Also, have you noticed any problems with having a high draft problem? So far it seems that my stove is putting out the heat, but I have no comparison on wether it is wasting heat because of the high draft. Any feedback would be appreciated.

 

[Lousyweather]

the draft pot only changes the voltage across the combustion fan VERY LITTLE, and, in a clean system there is very little restriction to draft, so, yes, there may very well be very little change in your magnehelic bwtween max and min settings on the draft pot....would have to research the difference bwtween min and max, but seem to be recalling somewhere about 5 volts difference? Im sure someone here might know the exact number....

 

[lbcynya]

...Can I ask what model type you ordered for your Magnehelic draft meter? Also, have you noticed any problems with having a high draft problem? So far it seems that my stove is putting out the heat, but I have no comparison on wether it is wasting heat because of the high draft. Any feedback would be appreciated.

I have a Dwyer gauge and it goes from 0-1" of water. Unfortunately, I don't have anything to compare, so I can't say whether it's pushing too much heat out the exhaust pipe. I'm a process control freak, so I'd rather go by the data vs. the seat of my pants...

I think the voltage range is 10 volts with the draft pot. Not much. If I turn the pot full CW I get about .52 and full CCW is about .49, on low draft.

Since the stove draft adjustments are pretty much worthless, would I have to restrict the exhaust pipe to get closer low draft readings? Only concern then is not enough air for high draft...or?

So far I'm real happy with the stove, but I would like to see if I can get things closer to specification. That's the pain that is my brain.

 

[lbcynya]

So we don't know or there's really nothing I can do about it???

 

[Delta-T]

keep in mind...the magnahelic measure negative pressure....not "draft" in the way we tend to think of it. This negative pressure is the differential of the intake and exhaust pressures, not a real measure of the volume of air being exhausted. Restricting the intake can increase the reading on the magnahelic....as can an excessive draft.

 

[GVA]

To add to what Delta-T said
If you stick the hose in the 3/8" hole for the firebox you would be checking for negative pressure in the firebox.
if you were to put the hose in the fresh air intake that would be a more accurate draft measurement.
However both should be fairly close, they are essentially the same thing.
Any way with that out there My stove did the same thing I could never get the low draft where the spec was, I didn't notice much of a difference in my burning vs other peoples burning.

My setup was straight out the wall about 3 feet of pipe.

Just wondering though if you put the stove in test mode to let the comb blower cycle between high and low draft or you are just adjusting the pot while the stove is running.

I've been outta the game for a while as most here know. But I still remember some things though with each day it's less and less.

 

[SmokeyTheBear]

To add to what Delta-T said
If you stick the hose in the 3/8" hole for the firebox you would be checking for negative pressure in the firebox.
if you were to put the hose in the fresh air intake that would be a more accurate draft measurement.
However both should be fairly close, they are essentially the same thing.
Any way with that out there My stove did the same thing I could never get the low draft where the spec was, I didn't notice much of a difference in my burning vs other peoples burning.

My setup was straight out the wall about 3 feet of pipe.

Just wondering though if you put the stove in test mode to let the comb blower cycle between high and low draft or you are just adjusting the pot while the stove is running.

I've been outta the game for a while as most here know. But I still remember some things though with each day it's less and less.

LOL

 

[lbcynya]

Just wondering though if you put the stove in test mode to let the comb blower cycle between high and low draft or you are just adjusting the pot while the stove is running.

I've been outta the game for a while as most here know. But I still remember some things though with each day it's less and less.

Thanks for the info. I tested with a cold stove and in test mode.