If you look on e-bay you can find a Magnahelic for around 30 bucks with shipping.  I just bought one a few weeks ago....

My draft was .75 and .70 WITH the pot turned all the way down......I have nearly the same setup....21 feet of 4” pipe into an existing masonry.

I’m going to try to put the OAK on mine this weekend.

http://cgi.ebay.com/Dwyer-Magnahelic-Differential-pressure-guage-15PSI-NEW_W0QQitemZ130174970942QQihZ003QQcategoryZ55825QQcmdZViewItem

Oh my low draft test is to close the door to the stove....then latch the latch slightly.....my stove will run with just the door closed but not latched......the further I press on the latch the higher the flames go....(this was pre magnahelic and quite barbarian)

Good luck!

You know if my stove had the test port on the back I would have had mine permanently hooked up, and watched the reading to tell me when to clean it, like in the picture above.
I think you would use it more than once to compare the initial install and then when you have a problem you can compare the readings.
If I still lived in MASS I would lend you mine but it is packed in a box somewhere I would have to look for days,and days to find it…
You’re dealer could check it for you.

I thought about leaving mine hooked up but it says in the gauge manual to not leave it hooked up to air hotter than 120 deg......

Perhaps they have another gauge for that but this one would not do it......

That’s a spiff idea tho.....kinda like an boost/vac gauge for your stove?  That would also be neat if I could put an EGT in too!

I cant wait to tell the wife that plan.....Yes dear we need an EGT for the stove.....

MrWinkey - 21 November 2007 07:46 PM

I thought about leaving mine hooked up but it says in the gauge manual to not leave it hooked up to air hotter than 120 deg......

Perhaps they have another gauge for that but this one would not do it......

That’s a spiff idea tho.....kinda like an boost/vac gauge for your stove?  That would also be neat if I could put an EGT in too!

I cant wait to tell the wife that plan.....Yes dear we need an EGT for the stove.....

It would be vacuum at that point so it would not be blowing hot air in the Mag.
There would need to be a transition to copper tube at the stove connection though that gets pretty hot.
I had mentioned the woodburners doing this on thier flues and they might be able to dial in thier fires easier, but they hve more stuff in the pipe to deal with plus higher temps. But if someone could do it say on a woodburners firebox then I’m sure it would work, and make the newb woodburners learn how to control thier stove quicker.
I’ll try to dig up an old thread from MSG on this..  I’ll be back.

EDIT*****
here it is
http://www.hearth.com/econtent/index.php/forums/viewthread/6748/

GVA - 28 September 2007 04:07 PM

BrotherBart - 28 September 2007 08:15 AM

Question for da pellet pros. How is a Magnehelic hooked up to a pellet stove to measure draft?

There is a bolt hole on the stove that you remove and insert the tube into.

Southbridge06GT - 03 March 2008 04:12 PM

GVA - 28 September 2007 04:07 PM

BrotherBart - 28 September 2007 08:15 AM

Question for da pellet pros. How is a Magnehelic hooked up to a pellet stove to measure draft?

There is a bolt hole on the stove that you remove and insert the tube into.

Any idea where this bolt is on an XXV?

The bolt hole is located @ the left lower side of the cabinet by the door.  It’s a hex bolt.
Download the PDF manual from Harman’s site, it’s listed in there.

Thanks cantman. I found the bolt but what should I do? just put the hose in the hole and follow the directions in the book? It tells you how to do the test just not how to hook up the gauge.

Southbridge06GT - 05 March 2008 10:21 AM

Thanks cantman. I found the bolt but what should I do? just put the hose in the hole and follow the directions in the book? It tells you how to do the test just not how to hook up the gauge.

I have the Harman Advance and did a self install. This past weekend I checked the draft and on high I got a reading of -.7 but on the low it stayed at .75 no matter where I adjusted the pot. Also when adjusting the pot I never heard the blower change speen either.
Any suggestions.
Thanks
Steve