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[coolidge]

How much can you add to the g200?

[mlappin]

With or without having to add a barometric damper? Slim would be the goto guy on this.

[slimjim]

I wouldn't do more than a couple of sections without a barometric damper, are you using it inside?

[schoppy]

I haven't asked this question of the factory but since this is a forced draft furnace, I am pretty sure you are not to use a barometric damper on the G series units. According to the National code, fan assisted furnaces use a barometric damper or draft diverter as the fan only gets the flue products to the exit point of the furnace. On power vented or forced draft furnaces they are to have a sealed venting system so the products of combustion will not enter the home or leak out of the chimney.

The manual does give the maximum recommended lengths both horizontally and vertically but there is no mention of a barometric damper.     

[slimjim]

You are right schoppy, I wouldn't want to use one on the inside of a building but if it's for Coolidge ( I know his is outside ) and he wants to add a lot then I would suggest it as it would break the constant draft created by the tall chimney.
Because we have been under the EPA mandate here for many years and the DEP's solution to pollution being dilution, forcing folks with older conventional boilers to put ridiculously tall stacks on their units and the increased amount of wood that they burn because of it, my solution would be a barometric damper.

[coolidge]

I have 5 ft on it now. Just curious if you could add more. Neighbors question who might be in the market for a replacement OWB.

[slimjim]

You can but with increased draft, efficiency does start going downhill!

[schoppy]

Hi Coolidge, I have 7 1/2' of vent on my G200 right now. I had to go that high to get 2' above the peak of the roof the unit is in. The manual says 15' max. I am going to try to reach a contact of mine who actually is a contributor to the National Fuel Gas code rules with this question.

I know on power vented gas furnaces the limiting factor is length and diameter of run combined with elbows so the resistance of the venting does not exceed a certain level set by the factory. Typically power vented or forced draft furnaces (induced draft for the G series) are not affected by draft considerations due to their sealed venting, rather it is their length and diameter that are the limiting factors so the resistance does not exceed the venter's ability to expel the flue products.

The G series is a lot like a high efficiency gas furnaces in that the heat exchanger is actually under negative pressure up to the point the venter discharges the flue products into the chimney which is why it should have much less smoke rollout when loading. I'll see if I can get more info.   

[schoppy]

Hey guys, got ahold of my contact and it was pretty much as I thought. The G series has only been approved with the designated venting and should not be modified.

Another reason a barometric damper should never be used on a solid fuel appliance is the dilution air mixed with the flue products will cause drastic cooling and creosote formation in the vent pipe, especially on outdoor units. On atmospheric vent, solid fuel units a damper in the vent pipe can be used to control the burn rate but these should not be used on power vented units like the G series.

I haven't talked to the factory but my guess is they would say pretty much the same thing.   

[slimjim]

Hey Schoppy, I'm not going to argue with you but I'm going to try to make a point here.
I know Coolidge and have known him for several years now.
I know the layout of his property and buildings.
I have been running, installing and servicing wood boilers now for well over 10 years.
I hold a valid solid fuels license in the state of Maine which is recognized throughout the North East.
( by the way, Coolidge also resides here )
Below Please find a couple of pics of the stack that for those who have seen me at shows, they may recognize as the very same stack that showed on my G 200 this last season, between heating my home and shop plus the show season, this stack has had well over 20 full cord of mostly green oak (30% moisture and higher), it has never had a brush or even a rag run through it.
By the way, I just delivered that boiler and fired it up again yesterday!
I wish I had taken some pics of the top of the tubes when I cleaned it for him but I didn't so Please take my word for it, there was 0 creosote anywhere past the firebox.
You are talking about a man who creates rules that he knows nothing about, heck I would doubt that he has ever seen an OWB let alone ever run or installed one, his rules are based on gas and oil that are indoors, would I put a barometric damper on a draft induced boiler in a building,  no way, but in Coolidges surroundings as well as his wife's concerns with wood smoke, if he wants to add some stack to get over the roof of his shop which would be I would guess 10- 12 feet then by all means Coolidge go right ahead but I would drop a tee in at the top of the stove and install a barometric damper to help reduce stack temp losses in the off cycle just like the indoor gas and oil industry has been doing for probably 100 years.
Do you see any creosote in the pics?

[schoppy]

You're right Slim about a lot of the rule makers that don't have real world experience and I'm not arguing with your experience just stating what the code is. I am not sure if he is aware of how clean the emissions are on the new gasser OWB either.

Have you ever had any problems with flue products coming out the barometric damper when the unit runs especially on days with less than ideal draft conditions?

If I understand your explanation it sounds like you are trying to eliminate excess air from being pulled through the unit when it is off? If that did happen it would rob stored heat from the unit.

Some situations call for thinking outside the box. The only thing to be aware of is all the other people (with a lot less experience) reading this which may have different units or installs and think they can do the same thing in their applications.       

[slimjim]

Rule makers,  I have been on the receiving side of their mistakes most of my life, almost 30 years as a trucker and then for the past 10 years with OWB's, thanks for starting out my monday morning with reminding me of the money and effort that they have cost me as well as my customers! It's no wonder that there is such turmoil in our nation today.
Flue products, I'm assuming you are referring to sparks and creosote, I have not seen it on any of the gassers that I have been a part of. Smoke, yes it can happen with the right wind and atmospheric conditions but if the gasser is running properly then there should be no creosote past the initial fire box and no sparks past the fire tubes.
Yes you hit the nail directly on the head with the stack temp losses in the off cycle.
Situations, I agree that a barometric damper and tall stack are not the perfect solution to all the issues  seen in the industry but I'm not the one that argued for mandatory laws like we have here in Maine or CT regarding additional stack height, in fact that was NESCAUM, DEP and the Maine lung association. Those three organizations spent a lot of money and effort to destroy an industry and based their argument on lies, in fact if you want to see something funny look at the front page of the report that NESCAUM used, it happens to be a picture of a CB conventional boiler that on first glance appears to be smoking like a burnt pig, however if you look closely, you will see that in fact the loading door is propped open and what you assume is smoke is actually steam coming from the vent tube, they chose to use that photo on the front cover of their report and when I confronted them in the hearings, their response was that they never SAID that it was smoke but they kept the photo anyway.
If they choose to knowingly lie to me on the front cover of a report and I know it, why would I believe anything they ever said again!

[schoppy]

Sorry about getting your week off on the wrong foot. You couldn't be more right about rule makers. Our EPA is so out of control it is ridiculous and this out going administration (thank God) has grown all regulatory agencies exponentially. This gives state regulatory agencies the belief they can do what ever they want and not answer to anyone. I never put it past the liberals to lie cheat or steal to get what they want.

I hope the Trump administration "Drains the swamp" like he campaigned on because if he doesn't I don't think the people will give him another chance.

Hope the rest of your week goes better Slim and have a Happy Thanksgiving.

[slimjim]

Thanks Schoppy, we are up in St Johnsbury Vt, temps are mild now but next week it will be cold here, glad we are doing the install now and not next week