How to verify operation of barometric draft regulator

I was I had a house today we’re absolutely everything was wrong. I came across this barometric draft regulator. I’ve tried googling this model I cannot seem to find anything. This is only the second time I’ve ever seen a furnace with a barometric draft regulator. So to say I know nothing about it would be an accurate statement. It was windy outside however the wind kept opening this thing on its own, this didn’t seem right to me. I’ve been doing a bit of googling and everyone I see seems to have some kind of weight on the outside and this had would look like a spot maybe for a weight but nothing there. I’m also including a link to a short video that I shot. If anybody knows more about these I would greatly like to learn.

I am most definitely recommending this furnace be serviced as it was last service to 7 years ago and there was signs of soot and leaks all over the unit.

This furnace was hooked up to an old unlined brick chimney. I was surprised at how clean the interior of the chimney looked as you can see from the picture.

This was on an old oil fired fuurnace. I’ve only ever seen two of those ever. I refused to operate the one today as the ducting and furnace was full of mouse crap. I’m not breathing that stuff. If you want to see the level of mouse crap in the house just ask and I will share that picture, it’s utterly vomit worthy that somebody lives in this house, but that’s a whole other thing.

YouTube link here


We have tons of oil furnaces here in Md and I have one in my own house. The balance screw is missing. It is used to balance the barometric draft for optimal performance and combustion. It should be installed. Having the furnace serviced by an HVAC tech is a good idea, they need to do combustion and air flow calculations to balance the damper. Not something you can really evaluate during a home inspection because of these calculations. They should also change the oil filter and clean the combustion nozzle as part of the service. Always a good idea to recommend this.

The exhaust should have a new continuous metal liner from the furnace to the top of the chimney but these were not commonly installed until recently and using old unlined chimneys is a common problem for older oil furnaces. Still a good idea to recommend having one installed here. Also will help to avoid moisture intrusion into the chimney and exhaust.

Here’s what that chimney probably looks like inside the home. You can see thermally that the exhaust easily escapes the chimney. This is from an inspection I did last week with very similar conditions. A lined chimney would not behave the same way and would not have much, if any, differential.



Hell! I don’t even know what that is

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No oil in Florida lol

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Awesome thank you so much I tried researching and I thought it was missing pieces and wanted to verify.

You would need to know the draft specs for the appliance and use a manometer to measure draft over fire and at the breech. The idea is to have just enough draft so their is enough pull to exhaust the combustion gasses and not so much that the heat is just lost through and out the chimney/vent. For a typical residential oil boiler about -.02-03inWC over fire is usually good. Sometimes too much draft can cause high CO, so the adjustments are done together with a combustion test. All this, however, is beyond the scope of a typical HI.

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New code won’t allow a gas water heater and oil burner to share the same unlined flue. Had one for years that shared the flue with our oil fired boiler. Recent WH replacement had to get an electric WH.

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