Doing the Barometric Damper Shuffle

Constantin

...of why barometric dampers are needed even on sealed combustion appliances. While I was reading the Opus IOM, I noticed they set aside a nice section on what to do with the damper. Then it struck me: Why was the damper shown pulling inside air? For that matter, why the Vacuum breaker on the inside?

Wouldn't it simply make more sense to hook up the intake air for the sealed combustion option to both the air intake of the burner <i>and</i> the barometric damper of the exhaust? Perhaps its just late on a Sunday night and I'm just easily befuddled?

Weezbo

What you suggest would sortta work...

a seperate outside air could be used to change the pressure over the boiler... on a dedicated supply air that is used for the burner things would be a bit different , the burner is pulling the air in and pushing it down the blast tube the barometric is equalizing over the boiler reducing the stack temp and sorta locking in the boilers heat..sorta. so simply tapping in a tee out of the drawtube out going air ,to the diffuser might present a few difficulties in patterns in the flame of oil burners. I can see a small tube that had a flat spray pattern that could be regulated in the air stream over the fire box to adjust barometric pressure. it probably would have to have a solenoid to close during pre purge and post purge....and have some small modulating spring like a erie zone valve ii hate thinking this much:) that allowed it to self correct for noticeable variances in temp...like old high limit lock outs in the stack.. it might be a way to do it,never thought about that idea before today. i just accepted that the inside air is in the 70 degree range and cool enough to close down some of the "lid" on 700 degree stacks to some where in the 200's 350 range ..outside air here is not as consistent in its temps or pressures in the stacks through out the year. however your idea might work. i am adventureous i might try to make some gizmo that would work...If only i had that fancy scientific super tech tool Firedragon mentioned a while ago:) i could drill a hole in the draw tube chuck the barometric drill a hole in a piece of flue pipe install a tube from point a to point b:) .... i think there fore i am:)

eleft_4

Vacuum breaker on the inside?

It's simply a safety, if the outside intake opening gets plugged.
.

Constantin

Yeah, the more I think about it...

... the more I'd want a dedicated air supply to the barometric damper. Otherwise, all sorts of funny business WRT air flow could happen.

On the other hand, what use is a barometric damper in a "tight" house (i.e. let's assume zero infiltration for arguments sake). If there is no "excess" air available inside to send up the chimney, wouldn't one want an external air supply to the damper?

eleft_4

Vacuum breaker on the inside?

It's simply a safety, if the outside intake opening gets plugged.


"intake terminal must be at least 12 inches above grade plus snow accumulation"

al

Unknown

The Opus

is not a true sealed combustion unit. It has an option of adding an outdoor air kit to supply outdoor air directly to the burner box or cover when equipped with a Beckett Burner. The kit includes a 4" collar that bolts to the burner cover, a blank off plate for the louvers on the burner cover base, a 4" elbow with vermin screen and a 4" relief damper. The damper is required in the event of the outdoor inlet elbow being blocked.

The flue barometric is still required to regulate and maintain over-fire draft in the event of adverse chimney conditions. Once again, the unit is not sealed combustion. In essense the kit is simply like introducing combustion air into the boiler room area except directly to the burner. The barometric needs to stay the way it is. The boiler also comes equipped with a "Residium Wave Resonator(RWR)" at the flue connection to "muffle" possible combustion noise almost completely. Hope this helps.

Glenn Stanton

Burnham Hydronics

Robert O'Connor_6

Glenn

How would the Opus perform on a 50'tall chimney with a 10 ft horizontal run?

Would condensation be a concern?

Regards

Robert

DaveGateway

Modified Combustion Air

15 or so years ago, when a customer mentioned they MIGHT be stripping furniture in the same room as the Armstrong furnace (SX 80) I simply blanked off the burner cabinet door louvers and brought in 6" CAI to the cabinet.

OEM recommended conversion? I doubt it. Still operating flawlessly? Yep.

I have since become a firm believer in direct vent. Sealed combustion requires no "house air". All indirect vent appliances should have dedicated combustion air provided IMO.

Unknown

Depending

on the chimney exposure to the environment, this may or may not be an issue. The Opus is not running significantly low flue gas temperatures (350°F+) so provided draft is not a real issue, it should be fine. As always, we would advise on a properly sized and installed flue liner to aid in overcoming these possible issues. If the boiler room is going to be as tight as he is discussing though, then this may not be the best application for a chimney vented boiler such as the Opus. A true sealed combustion unit would probably be a better choice.

The 88% to 90% efficiency of the Opus is AFUE and is acheived in the same manner as the Revolution Gas boiler. By modulating flow of water through the boiler and it's connected bypass, it is able to deal with return water as low as 55°F and not condense in the heat exchanger. Larger water contents and longer (more efficient) related burn times also contribute to the boiler's efficiency rating.

Robert O'Connor_6

Thanks Glenn