OIL FIRED DRAFT PROBLEM

Steamhead (in transit)

is only approved for atmospheric gas units. I'm not sure why.

Field is introducing a damper that's approved for oil-fired units, and it might be OK to use it on power gas-fired units. We'd have to verify that, though.

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Dan_63

oil fired draft problem

Tuning up a weil mclain wgo-4 oil fired boiler. found the draft before the barometric to be .5 inches of water. this is the best it will adjust to. the flue pipe from boiler to chimney is presently 7 inch. manufacturer will allow 6 inch so I will probably change it. has anyone any ideas to safely lower draft beyond the barometric damper adjustments??? also has anyone hear of an automatic draft damper being installed on an oil fired boiler??? thanks for any ideas

billtwocase

draft

Dan, I'm assuming thats a negative draft? readings between chimney and draft control -.05? doesn't matter as long as you are no higher than -.02 over the fire. That's the only place it matters. If you cannot get the current control to stabilize, than upsize, or add another. I don't care for stack dampers on oil fired. Been there done that with Flair years ago.. This boiler should be set up rear flue, as it is optional top/rear flue. Rear flue won't allow the air flow thru as much as top flue will. Stack temp will tell you that. peace

BMIN

draft

YOU COULD ADD ANOTHER DAMPER TO REDUCE DRAFT TO .04-.07 BREECH.

Dan_63

It is -.50 between the boiler and the barometric damper. I like the idea of moving the flue pipe to the rear outlet, it is presently out the top. I would have to add another 90 ell. What about changing the present 7 inch pipe to 6 inch??? The room this boiler is in is heated and I can not change that. A lot of heat is sucked up this barometric damper. That is why I asked about the possibility of an automatic flue damper which is common is gas fired systems. Thanks for any ideas...

billtwocase

high draft

That is high breech, but over the fire is all that matters. It needs to be no higher than a -.02 down sizing the smoke pipe will not help with lowering the draft because you will also have a smaller draft control

Dan_63

Thank you, But I do not understand why smaller flue pipe would not slow the draft over the fire??

Dick Charland

Smaller flue pipe won't slow the draft, just the volume of air that will pass through at a given pressure. If you had a 1" water pipe at 100 psi, changing it to 1/2" won't change the pressure. The important measurement is overfire draft. Putting a stack damper in will only control draft loss when the unit is turned off (standby loss). If the overfire draft is too high you can try 2 barometric regulators or in some cases a larger barometric installed accordingly.

Steamhead (in transit)

****'s right

"If the overfire draft is too high you can try 2 barometric regulators or in some cases a larger barometric installed accordingly."

Remember that older chimneys were designed to pull draft thru a bed of coal. This means they're wayyyyy over-designed for oil or gas firing. If you have one of these chimneys that can pull pets and small children up to the roof, you have to get the draft down somehow. Otherwise the excess draft will pull much of the heat out of the boiler, and can pull the flame right off the burner head, causing sooting.

Some Codes and AHJs frown on reducing the flue pipe diameter below the breech diameter. But a larger barometric- in your case an 8-inch on a 7-inch pipe- often works just fine. I'd try that first, then add a second one if needed. If the draft is still excessive, a chimney liner might be needed.

I still have my 25-year-old Flair Stack Pack damper, which came with my Burnham V-14 when it was installed. I've had to lube the gear box a couple times, but otherwise it works perfectly. On a mild day when the boiler runs a bit in the morning, then is off till the evening, it still has some heat in it when the burner starts again. The key is to set up the burner so it does not produce any smoke or soot. Every oil burner made since about 1980 is capable of this.


Field just came out with a damper for oil-fired boilers. When I get some time I'm going to try one.


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scrook_3

-0.50\" not -0.05\" w/ a baro?

You might need to make a neutral pressure point adjuster to limit the breech draft and volume of air sucked out the barometric. You could keep the 7" pipe and use an 8" Field M (vs. an RC or a 7") for maximum control. Pose the question at Alan's Oil Tech Talk too, http://www.oiltechtalk.com/ as the diehard oil guys all hang out there.

jim dowling_2

You never mentioned if it was a very windy day when you were servicing boiler.

Dan_63

Not a windy day and still -.50" .. Lots of good ideas, Thanks guys.

don_205

i would

I would check the firing rate and make sure it was firing at max.You'll se surpise with the results.

efo

Stack Dampers for oil units

Can someone tell me why stack dampers are legal for gas and not for oil units?

jimscout

Draft issues

What kind of stack temperature are you seeing and how tall is the stack.
Jim

World Plumber

Burner set up for firing rate

Do you have the right static plate and head/ is there too much excess air? I got called in the middle of a repacement on new years day, to do the setup. They went by the plates on the old boiler and then added a little. The draft was -.7 cycled off after 3 minuites run once it got up to temp. After changing the heads and down firing it to the load I was able to get the draft down to -.04 to -.06. Something to consider.

Dan_63

Thanks for the great ideas, I will check them out.