Barometric or Automatic Damper or Both???

Steamhead (in transit)

was available on oil-fired boilers in the late '70s thru most of the '80s. The motorized dampers used at that time were approved for use as retrofits, in the same way flame-retention burners were (and still are) approved for updating boilers with old-style burners. So in that sense, it wasn't "field-engineering".

Flair was the biggest maker of these dampers, but the low price of fuel and the fact that some of their equipment failed due to being installed on units with soot-making burners, killed Flair.

I still have the Flair damper on my V-14, installed past the barometric as instructed. It still works!

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John Barba_6

Auto. Vent & Barometric Dampers - One or Both?

The DOE EERE website talks about increasing the performance of boilers by retrofitting with an automatic and barometric vent dampers.

Can you or is it worth it to have both? I already have the barometric damper and want to eek out as much efficiency as possible.

Thanks & Happy Holidays.

Jeff

Brad White_203

Completely different functions

An automatic damper isolates the flue from the heated space between cycles.

A barometric damper (comparable to a draft hood on an atmospheric gas-fired appliance), decouples the chimney draft from that which has been established at the burner.

If you do not have a barometric damper or comparable function you will have among other things, a widely variable draft affecting your combustion, minute by minute.

John Barba_6

Brad:

Thanks for the info. I already have the barometric damper but am looking for additional options that will improve overall performance (and spend some money that the state is willing to give me for increasing the efficiency of my boiler).

I read somewhere that the auto damper can increase AFUE by as much as 2%. Will one interfere with the other or will they work independently as designed?

Thanks.

Jeff

Brad White_203

Independently

The arrangement I am most used to seeing is the automatic vent damper on top of the draft diverter (this on my former boiler, a Burnham 204). The idea is that when the damper is closed, any chimney draft through either the damper or the draft hood is blocked.

On oil and gas but in a wet-base natural draft application, I have seen it done both ways, auto damper just on top of the boiler or above the barometric. I really cannot say which is correct in that case for I do not know.

I will say though that the best application, in fact the only application, is the one which the manufacturer sanctions. Putting in after-market products can be hazardous. I have seen enough heat scavengers, bi-metallic vent dampers and other atrocities done, under good intentions, but with potentially dangerous results. Be warned. Go with what the manufacturer says.

Fred Harwood_2

Flue Damper

Another part of the energy saving equation is that a damper virtually eliminates conditioned air loss up the chimney between calls.

I am interested in who supplies oil-fired boiler dampers, and their availability. My supplier has had no luck, and a major manufacturer has delayed production.

Jeff_130

Honeywell & Field Seem to have them

I found them online. Check out this link.

http://www.hvacoracle.com/cgi-bin/store/oracle.cgi?x=parts&show_details=394&s=heating&cur=USD

Let me know how you make out.

Fred Harwood_2

Online

Here's what I get:

Automatic Vent Damper 6

Part #: D896A1277
Category: Boilers:Venting
Vendor: Honeywell
Price: USD $ 169.00 each

OBSOLETE-212,000 BTU D896A1277 D892A1177 & D80B1110 Replaced with Field 6" Vent Damper

No longer available. We will ship the Functional replacement on order.

Bob Harper

barometric dampers are required by code on all oil fired appliances unless the mfr. specifically forbids them. They regulate the draft and as Brad said decouple the flue from the appliance.

You can have automatic vent dampers and bimetallic vent dampers such as the old Amerivent. These are intended to reduce stack losses at standby and keep the chimney warm. However, they can in some cases lead to increased condensation by eliminating dilution air at standby.

Bimetallic dampers are hazardous since they are not interlocked with the primary controls. This is why Amerivent was pulled from the market and MASCO lost their butt in litigation. The leaflets sometimes failed to open fully making it a ventfree appliance with no safety interlock.

I agree with Brad's advice to avoid aftermarket components that are not listed for use with that particular model appliance.
Bob

Jeff_130

Bob:

Thanks for the info. Unfortunately, I have an American Standard A3 and can't find an info on the system as far as literature, etc. I'll have to check with my heating contractor to get someone in to advise.

Jeff

Steamhead (in transit)

The A-3

though built like a tank, is old enough that you might want to look at a completely new boiler. If that's not in the cards and it still has the original burner, upgrading to a high-efficiency burner will help.

Is this a steam or hot-water system?

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Leo_19

I wouldn't waste the money

I would just save and replace the boiler. I haven't had a customer yet that didn't cut their oil consumption by replacing these oil guzzlers.

Leo

Mitch_6

I have yet to see a motorized vent damper on a piece of

equipment with a barometric draft regulator. I have never been a big fan of venturing from manufacturer recommendations. I know there are some big repair over replace fans but I do not like the liability of taking designing and experimentation to the field.

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Fred Harwood_2

Flue Damper

Steamhead, please keep me posted should you hear of the overdue arrival of flue dampers. They are especially effective on older steam systems, which waste much boiler heat up-chimney between calls. Newer boiler packages may still benefit, depending upon conditioned space air losses up-chimney via the open barometric damper on a warm chimney.

Steamhead (in transit)

The first one I get

will go in my house.

I think flue dampers on oil-fired units will have a better chance now, since most equipment in use is equipped with flame-retention burners. They would have an even better chance if oil techs would stop setting burners for a "trace" of smoke. Flame-retention burners can run with true zero smoke when properly installed and tuned, so why look for a trace?

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Jeff_130

Steamhead:

Replacement isn't in the cards right now - besides the system seems to be working pretty well. I just had it cleaned and tuned and it is coming up at 80.5% efficient (which is in line with its historical numbers.)

I looked at the Burnham MegaSteam last year but replacing it with a system that is 86% doesn't make sense to me @ this point (by my math the additional 5.5% efficiency will only save about $300/yr making the payoff something in the 25+ year range).

Your thoughts?

Thanks.

Jeff

Steamhead (in transit)

That efficiency number

just shows how well the burner is working. It is not necessarily an indication of how well the boiler absorbs the heat and moves it to the water.

If we measured the A-3 boiler's AFUE it would probably be in the 70s, even if it had a newer burner.

We just replaced a Utica OU boiler with a MegaSteam and should have fuel-savings figures next spring. The OU is similar to the A-3 in its design, so it should be a good comparison.

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Jeff_130

I'd be curious to see what the numbers say. Your explanation makes sense; efficiency the burner tech gives me and AFUE are like apples & oranges.

A significant decrease in fuel consumption would change things dramatically. The guy who quoted me the Megasteam last year seemed awfully high. He basically double the boiler's list cost to cover labor/install.

Thanks to this website & Dan's books I will have a better understanding of the system when it comes time.

What are your thoughts the best Energy Star Rated Steam Boilers? (Burnham V8 & MegaSteam, Dunkirk Empire Series, Hydrotherm PB Series, Peerless EC/ECT, & the Pennco Keystone, Smith 8 Series, Utica Starfire III.)

Thanks.

Jeff

samazoseb.ov2436457

American Standard A3 oil furnace efficiency

For a hot water system (not steam) is there really a difference between the efficiency that the oil company technician measures and AFUE?

mark schofield

Field Controls has recently put one on the market.

http://www.fieldcontrols.com/pdfs/4325OilVentDamperSS.pdf

Steamhead (in transit)

The best one, hands down

is the MegaSteam.

All the others are vertical-flue, pin-type boilers. In this design, part of the flue passages is above the waterline. This reduces its heat-transfer capacity. Also, the pins are more difficult to clean.

The MegaSteam is a 3-pass boiler. Not only is this configuration easier to clean, but all the heat-transfer surface is below the waterline. This leads to better efficiency.

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