Outside Combustion Air

George -- Granjor Contracting

The boiler is a W/M with a Beckett AFG and Field Controls outside air kit on it. The chimney is masonry and at least 40' tall, with most of it inside the home. The question is -- There is a tremendous amount of air flowing thru the boiler when it is not running, there by increasing the standby loses. Any thoughts on how to control this? Thanks.

[Deleted User]

controlling combustion air

Beckett makes an "inlet air shut-off" part #5861. This will stop any air from going through the burner.

Weezbo

careful there...

pre purge is gonna be a minimum on that suggested lash up ....think about it for a cold sobering second.

clammy

baromitric damper

this is a oil fired unit correct did they install a baromatric damper on the smoke pipe and does that fresh air boot on the burner air inlet have a baromatric relief on it maybe some put ascrew so it wouldn't make noise good luck maybe just take off the air boot qand run 6 in rd to a oval x rd ell and use 6 oval with a dual stack for combustion air more then one way to skin a cat p.s. that air shutter for the beckett gun can cause promblems in the future when they get jammed or restrict air to the burner there great for sooting up a boiler and a 12;00 clock at night cleaning just my 2 cents peace

Weezbo

the barometric on the combustion is a for sure good idea.

George -- Granjor Contracting

yes on the barometric

There is a barometric on the smoke pipe ,and a relief on the fresh air. There is such a good draw on the chimney it just pulls it though the easiest path right thru the fresh air piping (4" rnd), throught the air boot, the burner, the boiler, and up the hot air goes. Thanks for your input.

Mike Kraft_2

The negative pull

Sounds like a very tall chimney.Riello did make a burner with a hydrolic air band to cover the squirrel cage.Great idea and cannot recall why it was eliminated.The only thing that I can see to reduce would be a properly sized chimney liner.Don't know if the chimney is oversized but reducing the diameter to the proper size may reduce loss..........marginally at best.

cheese

Mark Hunt

Are there


any problems running this boiler?

Sounds like you have some extreme draft potential.

Mark H

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George -- Granjor Contracting

Could be extreme draft

The chimney is over 40' tall and is inside the building envelope. The house sits up on a little hill with a constant breeze. The boiler lights off well, runs quitely, no soot. I'm going back next week with the draft guage.

Mark Hunt

If possible


Could you get the combustion numbers as well as the draft?

Beginning with light-off, run cycle, and shut-down.

Thanks!

Mark H

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George -- Granjor Contracting

I will get the numbers

The original problem, not yet solved, is what is percieved as excess cycling. This a fairly large house, 6300sq ft; 4 fan coil zones, 3 baseboard zones, a large radiant loop with tile warmers for 4 bathrooms,and a W/M 120 for domestic h/w. It's configured as a cold start. The boiler was origianlly packaged with a 1.45 nozzle, downfired once to 1.25, and then again to 1.10. On the coldest nights, 10 to 15 degrees, this thing has no problem keeping up and it still cycles. Before I did anything additional with controls I wanted to make sure all other mechanical issue were addressed. Thanks

Weezbo

i am thinking cold start...

maybe some speed drives on the fan coils blower motors ,and mixed returns ahead of a boiler bypass protection loop would help with the short cycling...maybe the outside air to the premix air is stuck open or is allowing too much outside air.

George -- Granjor Contracting

outside air premix

The combustion air comes directly into the burner thru a Field Controls air boot that replaces the air band on the burner. It's all outside air going to the burner. Thanks for thinking.

George -- Granjor Contracting

chimney

Its 8" sq masonry and at least 40' tall.

Dave Palmer_3

if

the draft is too high going thru the unit add a second barometric damper.Looks goofy but works great.We had some Slant Fins that would draft to much and pull the flame up into the sections,just a thought,dave

Maine Ken

Barometric

I have seen several places with similar setups. They all had too high of a draft. A second barometric stopped that problem. Why the makeup air? Is it a tight area?