Thread: 4" exhaust pipe

Mechanical inspector in Troy MI asking to change 3" exhaust to 4" for water heater saying that now it's in code, is it true and if it is true then why?

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Refer to the manufactures installation instructions.

I'm sorry this is my fault, I did not explain it good enough...
Every time, when I change out a furnace in Troy, MI this inspector makes me change smoke pipes on a water heater from 3" to 4". These are existing water heaters, they already passed all inspections long time ago, they are working great for 10 - 20 years and he makes me change the exhaust. Why?

"Smoke pipe" - is a slang for the 26 g. pipes, at least here in MI

Originally Posted by gennadiy edelshteyn

I'm sorry it is my fault, I did not explained it good enough...
Every time, when I change out the furnace in Troy, MI this inspector makes me change smoke pipes on the water heaters from 3" to 4". These are existing water heaters, they already are passed all the inspections long time ago, they are working great for 10 - 20 years and he makes me to change the exhaust. Why?

Good Lord, how long has this guy been with the city as an inspector? Because something passed years ago, doesn't make it right at today's standards.

rick

Originally Posted by gennadiy edelshteyn

Mechanical inspector in Troy MI asking to change 3" exhaust to 4" for water heater saying that now it's in code, is it true and if it is true then why?

Originally Posted by gennadiy edelshteyn

I'm sorry it is my fault, I did not explained it good enough...
Every time, when I change out the furnace in Troy, MI this inspector makes me change smoke pipes on the water heaters from 3" to 4". These are existing water heaters, they already are passed all the inspections long time ago, they are working great for 10 - 20 years and he makes me to change the exhaust. Why?

Huh? Why aren't you asking the Inspector?

BTW (by the way) I don't think you're sharing, even remotely, any of the important details for the situation you are asking about.

I'm not of a mind to attempt to extract them all from you.

I will ask is english your first language? (grammar, syntax, things get lost in the construction, and terms like "smoke pipe").

Seems you are working on multiple properties or dwellings, please explain.

Originally Posted by Rick Hurst

Good Lord, how long has this guy been with the city as an inspector? Because something passed years ago, doesn't make it right at today's standards.

rick

Well, this is my question: does anyone know that there are changes in the code, which make this particular inspector to demand changes in the exhaust?

There are lots of changes in the Code in various years. But that isn't really the point. You seem to be missing the relevant points all together.
- it is your right and duty to request the municipal inspector provide proof of why he is demanding the change. Ask him to cite the Code section. If he refuses to cite Code or sign-off on the install, call your attorney and threaten suit against the municipality.
- If he can't tell him you would be more than happy to change it IF he provides the Code section so you can do it properly.
- If you have been doing this so many years why don't you have a Code book?
- You have not provided enough relevant information for anyone who isn't a psychic to answer your question.

Since its a new installation the current codes would apply, but usually manufactures specs are acceptable to the authority having jurisdiction. This may be what the inspector is referring to.

There are lots of changes in the Code in various years. But that isn't really the point. You seem to be missing the relevant points all together.


- it is your right and duty to request the municipal inspector provide proof of why he is demanding the change. Ask him to cite the Code section. If he refuses to cite Code or sign-off on the install, call your attorney and threaten suit against the municipality.
This is a good point, but I'm an installer and I won't jeopardize my boss's relationship with one particular inspector!


- If he can't tell him you would be more than happy to change it IF he provides the Code section so you can do it properly.
As you should know inspector comes when the job is done...


- If you have been doing this so many years why don't you have a Code book?
People who making changes in code do it almost on daily bases! How much money should I spend on these codes?


- You have not provided enough relevant information for anyone who isn't a psychic to answer your question.
What else do you need?

Originally Posted by Raymond Wand

Since its a new installation the current codes would apply, but usually manufactures specs are acceptable to the authority having jurisdiction. This may be what the inspector is referring to.

Well, but manufactures specs asking for 3" pipes!

Gennadiy

Please excuse the rudeness as a lay person you have the right to ask your question without fear of ridicule by so called professionals.

Please continue.

Originally Posted by gennadiy edelshteyn

Well, but manufactures specs asking for 3" pipes!

In that case the inspector better have documentation and reasoning to support his demand because the manufacture has designed the system. Otherwise as Markus suggested contact your lawyer.

At first I thought you were referring to PVC for a power vented WH then I realized you were referring to a CAT I natural draft WH.

If you look at the sizing charts in the gas code, you will see that in most instances, a 40/40 NG water heater with a 3" draft hood will require a 4" vent connector to the common vent. You might be able to find a way around it with a very tall vent rise on with a short lateral offset on the vent connector. He isn't referring to a code change---he's just learned to read it.

HTH,

Bob,
Thank you!
I hope that eventually I have the answer, but just in case one more time:
Originally, it was a water heater's and 80% furnace's exhausts joined to the 5" B-vent pipe.
After I replaced this furnace with 95% one, from now on I must replace 3" vent with the 4" one - is this correct?

You need to distinguish btw the 'vent' and the 'vent connector', which have different venting requirements in the code.