Thread: Very tall vent flue

Is this water heater vent ridiculously tall or is just me? What code reference would pertain to this?

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Minimum of 3' above roof line and 24" higher than roofline at ten feet away, or 24" above peak if within 10'. It seems there should be some guy wires on this install, but the height looks correct.

Originally Posted by David Bell

Minimum of 3' above roof line ...

Huh?

Where did you get that?

That is a Type B Gas Vent, which is a minimum of 1 foot high, then higher based on roof slope, so maybe that may have to be 2 feet or so high above the roof.

... and 24" higher than roofline at ten feet away, or 24" above peak if within 10'.

You are thinking "chimneys", not gas vents.

Originally Posted by Frank Bombardiere

Is this water heater vent ridiculously tall or is just me?

Yes, way too tall. It needs support to keep it straight up and not falling over.

Sorry,,spent too much time in a hot attic today. Internal hard drive problems.

Well depending how for down is the draft hood of the appliance (IE water heater) I had a building that had a water heater that kept back drafting, and the vent terminated a foot off the flat roof, from the roof to the top of the water heater there was only 5' of rise in the flue pipe. I added another 5' section to the roof termination (and supported properly), and it solved the back draft problem. Had a good strong draw from under the draft hood.

It was plenty tall enough before it reached the roof. You will love this pic of the same vent at the top of the water heater.

Originally Posted by Frank Bombardiere

It was plenty tall enough before it reached the roof. You will love this pic of the same vent at the top of the water heater.

Wow.. that whole install.. wow... ok I am speachless.

You need roof support once you get over 5ft above the roofline. Should be rigid bracing and not guy wires, which only hold in tension. 3/4" EMT conduit is typically used but no screws into B-vent.

There is so much vent exposed to the cold air, any benefit from the additional height is offset by cooling the stack gases. This can actually be worse than a shorter vent with less exposed.

As for the stacked draft hoods and connectors, somebody ought to be shot for attempted murder.

and the plumbing.. no unions, .... and I am still speechless. Who ever installed that heater, should go to jail. That is one horrible install

Originally Posted by Ron Hasil

and the plumbing.. no unions, .... and I am still speechless. Who ever installed that heater, should go to jail. That is one horrible install

I had one the other day...new home final inspection, that the plumber installed the shut-off valve directly into the water heater...PEX on the other end of the shut-off valve. RED TAG...I called the plumber and he said he doesn't need a union because the shut-off valve will turn inside the PEX............He actually said that!

I didn't even show you some of the other stuff on that same water heater, see other pics. And the house was plumbed with PB to boot.

Originally Posted by Jerry Peck

....That is a Type B Gas Vent, which is a minimum of 1 foot high, then higher based on roof slope, so maybe that may have to be 2 feet or so high above the roof.

Jerry, it could be that CDN and US rules on this are different, and I don't have the codes to back this up (yet.... Maybe some other Canuck could help me as well), but it was my understanding that "L" and "B" vent chimneys need to be a minimum of 24" high above roof and 24" higher than anything within 10'. Brick chimneys, and metal chimneys for wood burning appliances, are 36" from roof and the same 24" higher than anything within 10'.

I am also turning to you to see if you know how close two metal chimneys can be to each other. I am thinking of situation on duplex or condo where the furnaces are 'back to back' on opposite sides of a wall that separates two adjacent unit and where the two chimneys would stick out through the sloped shingle roof that the two units share.

Thanks in advance for your, and anyone else's help.

Originally Posted by Egbert Jager

how close two metal chimneys can be to each other. I am thinking of situation on duplex or condo where the furnaces are 'back to back' on opposite sides of a wall that separates two adjacent unit and where the two chimneys would stick out through the sloped shingle roof that the two units share..

As far as I know, you can have two vents next to each other, separated by the distance or their respective flashings (should not be cutting the flashings up to put the vents closer together).

With chimneys, because they are wider than a vent, the answer might be different. This was discussed some time ago and Bob Harper provided some information, which I have now forgotten what it was and what was required/allowed.

Originally Posted by Wayne Carlisle

...PEX on the other end of the shut-off valve. ...

That's CPVC in the photo ain't it?

Originally Posted by John Arnold

That's CPVC in the photo ain't it?

Yes it is. But that is the discharge tube for the TPRV behind the inlet. It's trick photography, like the infamous Roof Beaver.

Per the listing of each appliance. I doubt you will find a separation stated by the mfr of types 'B' or 'L' vents or factory chimney but you should find it in the fireplace manual. Usually 18" OD to OD and 18" vertical staggering measured at the flue gas outlets.
HTH

If you are talking about my picture, which is the quote you used, it is CPVC but that is for the pressure relief valve and not the water inlet. I peeled the insulation back to look.

In California 12" above roof line.

The purpose of venting a gas or oil-fired water heater is to
completely remove all products of combustion and to vent
gasses to the outside air without condensation in the vent
or spillage at the draft hood (except in cases of downdraft
or poor stack conditions).
To assure correct venting, use a strong, gas-tight insulated
pipe with a cross section equal to that of the flue collar or
drafthood outlet and of sufficient vertical height.
During vent installation, avoid sharp turns, long horizontal
runs and improper pitches. Maintain proper support of vent
connectors and joints, observe clearances from all combustibles,

and top the vent outlet with an approved cap.

Fred Sweezer Sr.
http:Home Inspections in Long Beach, Los Angeles, Santa Ana and Surrounding Areas | Sweezer’s Inspection Service

Originally Posted by Fred Sweezer Sr

In California 12" above roof line.

Actually, the California code does not say that. It says basically the same thing the ICC codes say (because it is derived from them): (underlining and bold are mine)
- 802.6.2 A gas vent shall terminate in accordance with one of the following:
- - (1) Above the roof surface with a listed cap or listed roof assembly. (followed by more wording but I did not want to type it all, it also refers to Figure 8-2)
- - Figure 8-2 shows the roof pitch / minimum height above the roof chart, basically (if not exactly) the same as the ICC codes.
- - - flat to 6/12 - 1 ft
- - - 6/12 to 7/12 - 1.25 ft
- - - and continues up from there to
- - - over 20/12 to 21/12 - 8 ft

Well, ok why is the arverage hight from the roof line12 to 18 inches high above roof line?

Fred Sweezer Sr
Home Inspections in Long Beach, Los Angeles, Santa Ana and Surrounding Areas | Sweezer’s Inspection Service

Here are pictures of a new house I inspected last Sept. The vent pipe in the pictures is from a gas fireplace. This was a new development and this was the first house out of eight that was sold. I saw at least three others with the same problem. The missed the distance from a side wall by about 7' and the height by about 10'. They also had to bend the gutter to make it fit. Not sure how they fixed it but I think I would have put in an unvented fireplace.

Originally Posted by Wayne Carlisle

I had one the other day...new home final inspection, that the plumber installed the shut-off valve directly into the water heater...PEX on the other end of the shut-off valve. RED TAG...I called the plumber and he said he doesn't need a union because the shut-off valve will turn inside the PEX............He actually said that!

Falls under the same category as a city inspector telling me that mechanical protection for cabling was not needed in one area of a home because it was a residence---the mechanical protection was for commercial establishments only.