Atmospheric barometric conversion

Bob Bona_4

My error Chris, I was going by usually seeing the collector hood open on bottom. I thought it got covered by the looks of the pic. Carry on

ChrisJ

vaporvac said:

When my spill switches were installed it the screws did prevent an outward swing....it was done the the bottom. I felt intuitively that wasn't right (double-swing means opening in BOTH directions) and spent the time fiddling to get the screws in the other direction. That was a time-consuming pain which explained why it was probably wrong in the first place. Thanks for the clarification.

Not sure if you have the same spill switch or not, this one is a GSK-3.

The screw supplied from Field Controls goes with the head on the damper door side. It needs to be really tight, otherwise the door will hit it.

ChrisJ

Bob Bona said:

My error Chris, I was going by usually seeing the collector hood open on bottom. I thought it got covered by the looks of the pic. Carry on

The drafthood is covered but not the collector hood. The path for flue gasses to flow is unmodified.

Steamhead

And yet, 54 and other Codes have the force of law. So legally we have to comply, but who is liable when something installed to Code goes wrong?

I think I already know the answer...................

BobC

I noticed my damper occasionally would get hung up on the spill switch screw when my boiler was first installed. I ground about 1/16" off the tip of the screw and all was well.

Bob

ChrisJ

BobC said:

I noticed my damper occasionally would get hung up on the spill switch screw when my boiler was first installed. I ground about 1/16" off the tip of the screw and all was well.

Bob

How dare you modify that equipment! That equipment was designed and approved by the manufacturer!

BobC

And every f*cking item used in its construction was supplied by the cheapest supplier they could dredge up. I'll bet they ran out of the right size sheet metal screw and substituted the next size up. You were right when you said it's your equipment and you would do whatever you had to do to insure it's safe and efficient operation.

BTW if that dual acting damper has $5 of material in it I'll eat mine. Back in the day working in a manufacturing environment I quoted equipment at 3X the cost of the materials it took to build that equipment plus any out of the ordinary testing that had to be done.

Bob

RobG

BobC said:

And every f*cking item used in its construction was supplied by the cheapest supplier they could dredge up. I'll bet they ran out of the right size sheet metal screw and substituted the next size up. You were right when you said it's your equipment and you would do whatever you had to do to insure it's safe and efficient operation.

BTW if that dual acting damper has $5 of material in it I'll eat mine. Back in the day working in a manufacturing environment I quoted equipment at 3X the cost of the materials it took to build that equipment plus any out of the ordinary testing that had to be done.

Bob

3X. that's all? I'm sure the bean counters weren't happy with you!

BobC

That worked for 35 years; of course the military gear was a lot more because of the testing requirements.

Bob

ChrisJ

I don't know @BobC you felt the MG-1 was built poorly?
It seems pretty decent to me.

It's no Monitor Top, but I'd say it's far from junk

BobC

I think the MG-1 is built well but they are overcharging for it.

Once you have the design down pat, the cost of reproducing something out of sheet metal is pretty inexpensive. They can stamp things out at an amazing speed with little labor involved.

I used to get fairly complex chassis built out of 18 gauge steel for $12-15 delivered to my dock. That included getting inserts installed and plating. I'm talking small quantities here - 30 to 100 tops. If I could get above 250 or 1.000 the price dropped further.

Bob

ChrisJ

BobC said:

I think the MG-1 is built well but they are overcharging for it.

Once you have the design down pat, the cost of reproducing something out of sheet metal is pretty inexpensive. They can stamp things out at an amazing speed with little labor involved.

I used to get fairly complex chassis built out of 18 gauge steel for $12-15 delivered to my dock. That included getting inserts installed and plating. I'm talking small quantities here - 30 to 100 tops. If I could get above 250 or 1.000 the price dropped further.

Bob

Ah I see.
But, we don't know how many they're actually selling. Look at all the different sizes and the fact most things don't use them. How many could they possibly sell of one size per year?

They're stamped out and I'm assuming powder coated but then they need to each be calibrated, no?

BobC

I would think they sell more 6" than anything else because the bulk of houses with steam heat just don't need big boilers. I can see they would have to charge more for sizes with small sales. Once the program for the stamping machine is set, the cost for individual stampings is pretty low, you could even stamp out different sizes on one sheet to optimize material use.

Something like that is not calibrated unless there has been a change in material, then engineering will make whatever changes are necessary for proper operation. The tech has to determine if extra weight needs to be added to the chain for proper draft.

Bob

ChrisJ

BobC said:

I would think they sell more 6" than anything else because the bulk of houses with steam heat just don't need big boilers. I can see they would have to charge more for sizes with small sales. Once the program for the stamping machine is set, the cost for individual stampings is pretty low, you could even stamp out different sizes on one sheet to optimize material use.

Something like that is not calibrated unless there has been a change in material, then engineering will make whatever changes are necessary for proper operation. The tech has to determine if extra weight needs to be added to the chain for proper draft.

Bob

They claim it's calibrated specifically for 0.01" with out any weights added to the chain. I assumed this means someone calibrates each one on the bench, but I could be wrong.

The one I used is a 7" on a 6" pipe.

PMJ

I'm a little late to this conversation but I had a couple thoughts.

From an efficiency standpoint it appears that point of this is to keep to a minimum the amount of excess air going up the chimney - air which in most cases we already paid to heat so we are just wasting that. If like Tim says an open draft hood actually slows the speed in the flue down and keeps the combustion gasses in the boiler chamber hotter for longer then wouldn't restricting that send me in the wrong direction - vs the cost of wasting more heated excess air. Where those two things cross I don't know but I accept what has been said here that controlling it and getting the combution just right as Chris has done here rather than leaving it wide open is in fact more efficient.

But I must say that my mind goes right away to what seems to me must be a much larger efficiency issue which is where does the combustion/excess air come from. If it is air from inside the house that we already paid to heat vs air sourced directly from outside wouldn't that be the bigger deal? I know that code here won't allow an outside air supply to be piped directly to the boiler cabinet. But if I took a duct from outside and took it right to the grill at the burner and another leg to right at the open draft hood wouldn't that net result in more savings than anything else we could do to the draft arrangement? (Obviously this duct needs a damper too to be closed when the burner is off).

This actually was next on my list.

Charlie from wmass

Buderus uses that fresh air setup with their cast iron power vent boilers

ChrisJ

I had wondered about feeding the barometric with outside air but code doesn't allow it.

PMJ

ChrisJ said:

I had wondered about feeding the barometric with outside air but code doesn't allow it.

Isn't it just that it can't be hard piped? You can bring it a few inches away and leave it open. Will achieve 90%+ of what you are trying to do.

ChrisJ

PMJ said:

ChrisJ said:

I had wondered about feeding the barometric with outside air but code doesn't allow it.

Isn't it just that it can't be hard piped? You can bring it a few inches away and leave it open. Will achieve 90%+ of what you are trying to do.

Yeah, but then I also have a 7" wide open pipe dumping ice cold air into my basement.

PMJ

ChrisJ said:

PMJ said:

ChrisJ said:

I had wondered about feeding the barometric with outside air but code doesn't allow it.

Isn't it just that it can't be hard piped? You can bring it a few inches away and leave it open. Will achieve 90%+ of what you are trying to do.

Yeah, but then I also have a 7" wide open pipe dumping ice cold air into my basement.

I plan to put another automatic damper on that one too so it is only open when the burner is on.

ChrisJ

PMJ said:

ChrisJ said:

PMJ said:

ChrisJ said:

I had wondered about feeding the barometric with outside air but code doesn't allow it.

Isn't it just that it can't be hard piped? You can bring it a few inches away and leave it open. Will achieve 90%+ of what you are trying to do.

Yeah, but then I also have a 7" wide open pipe dumping ice cold air into my basement.

I plan to put another automatic damper on that one too so it is only open when the burner is on.

Will I ever get that $100-150 back?

PMJ

ChrisJ said:

PMJ said:

ChrisJ said:

PMJ said:

ChrisJ said:

I had wondered about feeding the barometric with outside air but code doesn't allow it.

Isn't it just that it can't be hard piped? You can bring it a few inches away and leave it open. Will achieve 90%+ of what you are trying to do.

Yeah, but then I also have a 7" wide open pipe dumping ice cold air into my basement.

I plan to put another automatic damper on that one too so it is only open when the burner is on.

Will I ever get that $100-150 back?

I suppose the smaller the system the less sense it makes as the cost of the damper only goes so low. Quick look for me has my current loss at maybe 2% of the total bill so $50 a season or so to be gained. Paid for then in 3 years and over the life of the system why not keep the money? What did you spend on the stuff to do what you did in this thread and what is the savings do you think?

But the bigger reason for me is stopping the drafts - just a comfort issue. It is coming in somewhere and always annoying. Seems to me you have to pick the hole and automate it somehow - and that hole is best right at the boiler.

Charlie from wmass

I meant piping the combustion air to the burners. The barometric is meant to help balance the air in the room with the draft of the chimney.

Tim McElwain

What is the total BTU of all the equipment in the combustion zone?

What is the dimension of the room in which all the equipment is located?

Is there a dryer in the room?

By the way to clear up something I said:

"If like Tim says an open draft hood actually slows the speed in the flue down and keeps the combustion gasses in the boiler chamber hotter for longer then wouldn't restricting that send me in the wrong direction - vs the cost of wasting more heated excess air"

When you install a barometric you actually improve the ability to control the flow velocity of heated gases leaving the breech and improve over all operation. The three "T's" Time. Temperature and Turbulence are also improved. Then any change in air for combustion (draft) will be automatically corrected by the double swing barometric.

Chris your attempt to control air for combustion may be a little excessive lets run the numbers I ask you for and see if adequate air is available already without any modifications or introduction of air from outdoors.

Then as an alternative a fan in the can could perhaps be used.

ChrisJ

Tim McElwain said:

What is the total BTU of all the equipment in the combustion zone?

What is the dimension of the room in which all the equipment is located?

Is there a dryer in the room?

By the way to clear up something I said:

"If like Tim says an open draft hood actually slows the speed in the flue down and keeps the combustion gasses in the boiler chamber hotter for longer then wouldn't restricting that send me in the wrong direction - vs the cost of wasting more heated excess air"

When you install a barometric you actually improve the ability to control the flow velocity of heated gases leaving the breech and improve over all operation. The three "T's" Time. Temperature and Turbulence are also improved. Then any change in air for combustion (draft) will be automatically corrected by the double swing barometric.

Chris your attempt to control air for combustion may be a little excessive lets run the numbers I ask you for and see if adequate air is available already without any modifications or introduction of air from outdoors.

Then as an alternative a fan in the can could perhaps be used.

Hi Tim,

The basement where the boiler is located is around 350 sqft. Only other appliance is a power vented 50 gal water heater. Basement is also connected to four crawl spaces. Everything is very drafty down there so I have no doubt there is plenty of combustion air, and then some. I really need to fix the crawl space doors, once that's done we'll see where we're at.

Boiler is currently 125,000 btu input, water heater is 40,000 btu.

I'm curious, what exactly is "a fan in the can"? Sounds like a bathroom fan?

Fred

"I'm curious, what exactly is "a fan in the can"? Sounds like a bathroom fan? "
@ Chrisj See: http://www.theenergyconscious.com/fieldcontrols-ha013.html

ChrisJ

We didn't have too much success with the blocked drafthood + barometric.

Off the top of my head, O2 was over 13% even with the manifold pressure cranked up as high as we could get it, 5" or so. Opening the EG-45 drafthood dropped it a lot, but still wasn't great.

Swapping in the EG-40 drafthood and a brick as a baffle got us down to almost anything we wanted but the safest setting resulted in this. I believe this was just over 4" WC manifold pressure.










So far, the barometric isn't doing anything but I'm leaving it in to see if it does anything when it's actually cold outside.

ChrisJ

I'm amazed.
When we were testing it was in the mid 50s out and the barometric was doing absolutely nothing with the drafthood operating.

Boiler just fired and it's 40F out and the barometric actually opened slightly. I guess it is going to be beneficial afterall.

Charlie from wmass

By going to 4" you have increased your fire rate. Have you clocked your meter?

ChrisJ

Charlie from wmass said:

By going to 4" you have increased your fire rate. Have you clocked your meter?

No, why?

Should be approx 142,500 input now vs 125,000

Charlie from wmass

Works out to 50 square feet more steam than you had. This will mean you may shut off on pressure now.

Fred

@ChrisJ , I'm confused. I thought you downgraded you EG45 to a 40 because you didn't want/need the output of the 45. Doesn't this take you back to close to what the 45 output was?

ChrisJ

Charlie from wmass said:

Works out to 50 square feet more steam than you had. This will mean you may shut off on pressure now.

Highest we saw today was 1" wc

Charlie from wmass

So you doubled the pressure! !!!!

ChrisJ

Well, what would you do?

Run the lower default pressure with a lower combustion efficiency?

Doesn't seem to make much sense. We all know 1" WC steam pressure is harmless, as is 1.75".

The same block as an EG-45 has an extra burner and is 150,000 input. So, we're approaching that with less O2.

Tim McElwain

I hope you know what you are doing because you are playing around with design equipment and unless you are an engineer or highly trained on combustion you could surely hurt yourself or someone else. I really have been uncomfortable with this since the beginning.

JStar

Chiming in here. I was with Chris doing these modifications. Combustion analyzer and personal CO meter were running throughout the entire process.

Tim McElwain

Glad you are involved Joe but I am not sure Chris is really going get things to work any better than they were designed to work. It seems like a lot of work to accomplish a very small change in operation if any at all.

I have found in some cases removing the draft hood and installing a barometric did not change things much. Then again I have had some real good experiences with eliminating the draft hood and going to a barometric especially on draft hoods that are external of the boiler.

JStar

I think that Chris and I are particularly interested in the proof of concept and to witness what changes can or should be made to atmospheric boilers.

ChrisJ

Tim McElwain said:

Glad you are involved Joe but I am not sure Chris is really going get things to work any better than they were designed to work. It seems like a lot of work to accomplish a very small change in operation if any at all.

I have found in some cases removing the draft hood and installing a barometric did not change things much. Then again I have had some real good experiences with eliminating the draft hood and going to a barometric especially on draft hoods that are external of the boiler.

Tim,
My hopes were to make the system safer, with perhaps a gain in efficiency as an added benefit. Unfortunately the system ran much worse with the drafthood blocked.

I really liked the idea of having a setup where I could look over at the boiler running and see the damper leaning in giving me confirmation that I have good draft. With the drafthood, who knows?