Manometer recommendation

  • Active since 1995, Hearth.com is THE place on the internet for free information and advice about wood stoves, pellet stoves and other energy saving equipment.

    We strive to provide opinions, articles, discussions and history related to Hearth Products and in a more general sense, energy issues.

    We promote the EFFICIENT, RESPONSIBLE, CLEAN and SAFE use of all fuels, whether renewable or fossil.

cabinwarmer

Member
Sep 11, 2020
183
SE PA
Good Day,
I am looking for some guidance and advise around a useful manometer to check my newly installed GM 60 wood stove. This is not a commercial deal, just a home owner that would like to verify and better understand my draft through various conditions. I have seen several, some digital some analog. All seem to have average reviews. Thanks in advance for your help!

Dave
 

peakbagger

Minister of Fire
Jul 11, 2008
6,399
Northern NH
Dwyers are pretty much the standard for analog. Unless you stomp on it it cant get out of calibration. Digital can get out of calibration.
 

cabinwarmer

Member
Sep 11, 2020
183
SE PA
peakbagger, thanks. Analog sounds find to me. I have been on the Dwyers web site. Which model comes to mind? I don't think I want anything stationary.
 

peakbagger

Minister of Fire
Jul 11, 2008
6,399
Northern NH
Last edited:

cabinwarmer

Member
Sep 11, 2020
183
SE PA
Got it, that is a popular one, yes. I think begreen showed it as well in another post. Question, how does this unit measure? You simply plug in the air tubes and shut the stove door? Open and close the air inlet and record the measurement changes?
 

brenndatomu

Minister of Fire
Aug 21, 2013
6,351
NE Ohio

peakbagger

Minister of Fire
Jul 11, 2008
6,399
Northern NH
Got it, that is a popular one, yes. I think begreen showed it as well in another post. Question, how does this unit measure? You simply plug in the air tubes and shut the stove door? Open and close the air inlet and record the measurement changes?
Depending on what you are reading you only hook up one tube and other is open to the room. You fill the device with gage oil ( dyed water), level it with that built in bubble level, zero the unit with the tube detached and hook the tube up to the stack. The difference between the air pressure in the room and inside the stack will move the liquid line to the corresponding pressure reading in inches of water which is then read off the permanent markings in the gauge. You need to able to find a spot to drill and tap the stove and the stack as other wise the connections will leak. easy with a steel stove but not so easy with cast iron and every time you drill cast iron you could start a crack

On occasion folks also want to measure the pressure difference between the outside and the inside of the house to ensure that the house is not under enough vacuum to keep the stove from drafting. You

I mostly use them for testing fans. I have some slack tube versions that measure 60 inches of water. I prefer the slack tubes as there are fewer moving parts and easier to set up but they are useless for fine measurements on a stove. I must admit I have never used one on my boiler. Its pretty darn obvious if its got enough draft on it, the smoke goes up the chimney if it has and out the loading door if it doesnt. I have box of various range magnahelics left over from industrial filter systems. They use them to measure the pressure drop across filters
 
Last edited:

Bad LP

Minister of Fire
Nov 28, 2014
1,658
Northern Maine
I think the Mark II Series 25 is popular. Its got the built in level so its easy to set up temporarily. You do need to hit the hardware store and get the right thread fittings and tubing that can take a vacuum. Getting the dyed water in the tube can get messy.

A member has this for sale https://www.hearth.com/talk/threads/dwyer-magnehelic.185541/ It has more range but more prone to getting out of calibration https://www.hearth.com/talk/threads/dwyer-magnehelic.185541/

I ran copper tubing for about the 7 feet it took to get there. Copper is thru the hole I drilled in the stove pipe, runs around the space to a compression fitting, barb fitting and a short length of the factory hose to the meter. Works perfect. What I found interesting is that there is a lot of fluctuation throughout the year in all seasons.
 

cabinwarmer

Member
Sep 11, 2020
183
SE PA
I see, wonder if I could use the digital probe hole? It is 18 inches up from the stove top. OR, could you snake it out the inlet?