Barometric Dampers for atmospheric appliances

Smith19

I recently posted about issues with my hot air furnace - however I have a completely different question. I have been hearing lately about barometric dampers and spill switches being fitted to atmospheric boilers and water heaters. This is obviously a violation that would void warranties - but what are peoples thoughts on this? Is it a good thing to do? Is it downright dangerous? Some say that it's safer than a draft hood.

Thanks!

RayWohlfarth

I have heard some people have done that and swear by the results. I looked at converting one problem boiler to barometric and I have two big stopping blocks. The first is I would think the manufacturer would do that instead of a draft hood as the flue would be smaller and less expensive if it worked as well. The other thing that scares me is if something happens and the manufacturer looks at it and says it was not installed according to their manual and the liability would fall on me. I do not like lawyers. Good luck

Tim McElwain

Draft hoods actually disconnect the appliance from the flue.
with that in mind there are times when replacing the draft hood with a double swing barometric is a good solution. I have done many of these and usually have been able to get manufacturers to sign off. Especially when I was the last hope for keeping this thing running and could prove better venting with the barometric. That includes a better combustion analysis.

Get in touch with Jim Davis who posts here from time to time he can give you even more positive results with this process.

RayWohlfarth

Tim,
Wow I am really surprised the company signed off on that. I spoke with a couple manufacturers and they simply said I could do whatever they wanted but would not put anything in writing. You must be more persuasive than me.
Ray

BobC

Maybe Tim got the ok before lawyers ruled the planet.

Bob

Tim McElwain

My lawyer actually drew up the first proposal I needed to send to a manufacturer. This was after I was in business for myself. I had previously installed barometrics under the covering of the utility I worked for based on the AGA study done back in the 90's.It is simple if you have "curtain effect" taking place then the appliance is unsafe so you make it inoperative. The addition of the barometric will allow it to run correctly and safely so it is really a no brainer. I have actually stood in basements with the local utility,local inspector, landlord and equipment manufacturer giving them those options and showing them the results in front of them with the barometric in place. So what do we do put it back the way it was and leave it on and kill someone duh!

The truth be known a lot of manufacturers do not allow conversion burners to be installed on their oil fired equipment. They void the warranty, my solution I assume the warranty. I have installed over 3,500 conversion burners and have never had a problem. I also have never had to honor any warranty I gave.

captainco

I first started selling barometrics on gas boilers in 1980 and removing drafthoods. The main reason was we were putting reclaim coils in the flue to recoup flue loss. They don't really work above drafthoods. But something I first discovered in 1980 was a rising CO senario. A boiler had run for 20 minutes with no measureable CO but then out of nowhere the CO jumped over 5000ppm. There were no digital CO testers back then but I was using a glass tube that was plugged into a commercial combustion analyzer. Rather than doing a single timed test I just put the glass tube in and figured there either was CO or there wasn't. Anyway, l did not know why this happed or could I find anyone else that even knew what I was talking about. The problem was no one had ever done continuous CO testing in the field.

The boiler was retrofitted with a hot water reclaim coil in the flue. The rear drafthood was blocked off and a barometric installed above the hot water coil. The CO problem disappeared? This is when I really spent all my time studying venting, drafthoods and barometrics. I couldn't believe everyone was so naive. Drafthoods are designed to keep appliances running unsafe for 3 different conditions. !. Prevent draft from venting the flue gases 2. Keep pilots lit during downdraft and negative pressure conditions. 3. Allow equipment to operate if the flue gets plugged.

37 years later, tens of thousands of barometric retrofits, not once has there been a safety issue or a mechanical failure because of them. On the other hand, these problems were eliminated 100%. In some cases, equipment that the manufacturer had already voided their warranty because of failures, never failed again. Drafthood excuse manufacturers from the liability of venting. Barometrics would cause them to be liable.

If you tracked CO poisoning a deaths as I do, you would see that plugged flues and drafthoods without safeties cause the majority of poisoning and deaths.

Drafthoods prevent venting and eliminate all control of combustion air to burners and that to me is scary!!!

RayWohlfarth

Tim and Captain I am impressed. I was nervous about switching over to a barometric instead of the draft hood. Thanks for teaching this old dog some tricks.

captainco

Another nice things about barometrics is they only need one safety spill switch whereas most drafthoods should have at least three.

Besides controlling venting and combustion air barometrics minimizes the chance of condensation in the flue because they keep the flue gases hotter by reducing dilution air.

Barometrics can also prevent condensation in flues of induced draft equipment better than liners. They almost got approved as an alternative to liners but Field Controls decided not to spend the money because so few people knew about them. They can minimize condensation in liners also. Because gas barometrics are double acting they are a visual tool to determine if the flue or liner is undersized or restricted. Of course because of the safety shut-off that should be included they make sure the equipment shuts down.
I have been told by industry authorities that this would cause a nuisance but I figured death was a bigger nuisance.