Dealing with chimney contractor

gennady

Please advise - we are currently installing a boiler of 275.000 btuhr ( there are 2 existing water heaters 2x50.000 bthuhr each) input on a project where the chimney contractor is less than pleasant. They insist on installing a 14" flex liner 70' high, first without even listening to the size of the boiler and then just disregarding what we've told them. I think chimney is way oversized BTW. Tables at fuel gas code pointing to 10" diameter chimney. My question is this - has anyone had experience with a chimney contractor not sizing the chimney to the boiler and how did you handle the situation? We have yet to come across a company like this. Thanks in advance.

ChrisJ

The chart I have for multiple appliances into a flex liner suggests even an 8" at 45' would be sufficient. 10" sounds too big too.
14" 70' tall sounds insane.

nicholas bonham-carter

Can you get a second opinion?--NBC

j a_2

Nfpa 54. Has great charts,,as well as manufactures of the flexi crap, provide the ratings....call the manufacture present him with the details and he may or may not help you...Definitly a mistake you don't want to go thru...Ultimitly, it's on the installer, he had best know his business, people hate it when they get c o poisoned...Now that's a bad day...Go by the book....

Zman

The boiler manufacture or rep can run the calcs for the flue. It would be hard for the owner or the chimney contractor to argue with that.

gennady

Thanks for reaffirming my calculations. Unfortunately we can't get a second opinion because the owner contracted the company separately. But since we are on this project with these guys, how can we approach this sizing issue without upsetting them even further? We can't just leave the sizing as such because at the end we will be responsible for proper boiler operation and we will be signing chimney portion of schedule C.

hot_rod

Send them and the owner a letter documenting your calculations and recommendations based on the tables you used, either the manufacturers or NFPA 54?. If you proceed with their system and problems arise you have it in writing. Have them sign the letter.

j a_2

hot rod said:

Send them and the owner a letter documenting your calculations and recommendations based on the tables you used, either the manufacturers or NFPA 54?. If you proceed with their system and problems arise you have it in writing. Have them sign the letter.

Hot rod I would just flat out refuse if I knew for a fact it was wrong...no idea what schedule c is...

newagedawn

fire the contractor and hire another one, that will give you time to sort out the required flue size, is the 275 boiler flue 8"

ChrisJ

newagedawn said:

fire the contractor and hire another one, that will give you time to sort out the required flue size, is the 275 boiler flue 8"

It sounds like the liner is already installed and the contractor doesn't want to change it.

Bit late to just fire them, I think that's issue.

I also think @gennady is right, this is going to cause endless problems and they're going to be his problems.

HVACNUT

I would write a letter voicing your concerns. Have the G.C. and the owner of the chimney company sign it, and maybe get it notarized.
Do you have a copy of the the proposal? It should state "X" boiler installed, connected to new "Y" chimney. All work to code, and per manufacturers specifications, yada, yada.
Bottom line is C.Y.A.!

Zman

Ill say it again. Get the boiler manufacture involved. They have engineers on staff that do nothing but calc this stuff. Show the manufacture engineers calcs to the owner and tell them that the warranty will be void if the job is not done per manufacture spec.
I am sure you are right. You just need to send it to a higher authority to convince everyone else.

ScottSecor

I agree that the chimney liner should be sized properly.

However, I must admit that I've been in countless basements and boiler rooms that had boilers vented into over-sized masonry chimneys. That being said, on a few occasions did we witness poor draft, unstable flame or unsafe conditions. An over-sized metal liner is probably better than no liner at all. If the new liner is 14 inch, I suspect the chimney interior is at least a 16" square and perhaps much larger.

If all three appliances are typical gas fired atmospheric equipment you may be just fine with the 14" liner. Keep in mind when just one of the water heaters is operating even the correctly sized liner (eight inch I gather) will be grossly over-sized!

ChrisJ

ScottSecor said:

I agree that the chimney liner should be sized properly.

However, I must admit that I've been in countless basements and boiler rooms that had boilers vented into over-sized masonry chimneys. That being said, on a few occasions did we witness poor draft, unstable flame or unsafe conditions. An over-sized metal liner is probably better than no liner at all. If the new liner is 14 inch, I suspect the chimney interior is at least a 16" square and perhaps much larger.

If all three appliances are typical gas fired atmospheric equipment you may be just fine with the 14" liner. Keep in mind when just one of the water heaters is operating even the correctly sized liner (eight inch I gather) will be grossly over-sized!

Absolutely.
And with a 14" it's three times as bad as a correct setup. That's not the way to do things. a 14" pipe can in theory vent 3 times as much as an 8 inch.

I do get where you're coming from though. You're saying it's probably not the end of the world.

Rich_49

hot rod said:

Send them and the owner a letter documenting your calculations and recommendations based on the tables you used, either the manufacturers or NFPA 54?. If you proceed with their system and problems arise you have it in writing. Have them sign the letter.

As Bob stated , make sure the building owner or representative is also aware . A Hold Harmless Agreement is a powerful tool along with making others who disagree do a bit more critical thinking .

JohnNY

Can an oversized liner be compensated for with a specially selected chimney cap?

Larry Weingarten

Hi, The water heaters are unlikely to be able to heat up such a large vent... so spillage is almost a certainty. I'd get all parties involved and not allow this unsafe condition to be created.

Yours, Larry

j a_2

I have no idea why anyone would take responsibility for such a thing...They hopefully will tell the ocupents of the property the potential problem....Some one is making a real stupid decession, if I read the op correctly

gennady

"Thanks everyone for the advice, I really appreciate it. As you mentioned, we will provide them with our calculations for their review and request theirs to prove that their sizing is correct. As of now we haven't been able to get any calculations from them. "