High Efficiency Exhaust Facing up OK?

cj5

Had my high efficiency boiler exhaust replaced to offset it more from the intake. But the guys put a 45 degree are the top, not a 90 degree. I've never seen that done before. I'm concerned dirt, leaves, pine needles, roof shingle debris, etc are going to get in there and fall into the boiler and clog up the flow and cause corrosion. See attach image. I asked them abiut and and they said that's how it should be. Should I have them come back and change it so the exit faces horizontal?

pedmec

What happens when you get a torrential rain?? Have them put a 90 on it

kcopp

Some Mfg spec for that set up.
They want the exhaust to be directed up and away so as to not have recirc of flue gasses.
What is the make and model?

cj5

It's a Navien NCB-240.

HVACNUT

Concentric vents exhausting out of roofs always face up. Never an issue because the exhaust is also a drain. Check the installation manual though because some manufacturers spec an inline Tee with a drain on the horizontal run. Manufacturers are very specific on venting. It's all in the book.

dko

yellowdog

The boiler manual will give you all of their accepted methods of termination. Just because the installer wants to do it a certain way does not mean it is accepted by the boiler manufacturer. Open the manual! That is hack work anyways. Get it corrected.

pecmsg

That tight 90 deg turn adds more restriction then a sweep 90 degree. 

cj5

Regarding that 90 turn, is a sweep required per code? It is a very short run.

The installation manual just calls out a 90 degree elbow effectively adding  5 feet. Don't know if that assumes a sweep or tight turn.

cj5

Regarding what the manual says, thank you for the encouragement to look at it. I am but it leaves out details that I am unsure if the code regulates or which one overrides in case of conflict. Current the manual says intake and exhaust should be 1ft vertically offset. CT code seems to say it should be 3ft ....maybe. Reading the code is more complex to fully understand so am unsure.

It does make sense that a vertical exhaust would need a cleanout but that isn't in the manual and haven't come across it in the code.

Thanks for taking the time to provide me with this valuable information.

pecmsg

You site code……was this inspected and did it pass?

code is the minimum standard. 

ChrisJ

cj5 said:

Regarding what the manual says, thank you for the encouragement to look at it. I am but it leaves out details that I am unsure if the code regulates or which one overrides in case of conflict. Current the manual says intake and exhaust should be 1ft vertically offset. CT code seems to say it should be 3ft ....maybe. Reading the code is more complex to fully understand so am unsure.

It does make sense that a vertical exhaust would need a cleanout but that isn't in the manual and haven't come across it in the code.

Thanks for taking the time to provide me with this valuable information.

It says 12" minimum.
That means in your area 3' if local code says 36" minimum.

GGross

My primary issue with this setup is that it isn't really supported at all leaving the flue pretty vulnerable to being taken out by a strong gust of wind. Personally I would have recommended moving the intake and leaving the flue. As far as minimum separation goes.... It is just that, a minimum. There are countless examples in my own experience of flue terminations that are within manufacturer spec, and pass code, but still recirculate or otherwise have issues.

hot_rod

the exhaust vent looks to be CPVC, do that is a pressure fitting ell

DWV fittings come in 3 different sweeps, vent ells standard ells, and long sweep

Maybe that short turn ell adds a few more feet, but it looks like a short run anyways

It looks like it has the screen installed, so I imagine it works fine. Vertical vents get more rain than that 45 will. But the manual is the final word.

realliveplumber

The manufacturers appliance specific instructions would override local and national codes.

They engineered it and paid to have it listed and labeled. You would install it the way they say to install it.

ChrisJ

realliveplumber said:

The manufacturers appliance specific instructions would override local and national codes.

They engineered it and paid to have it listed and labeled. You would install it the way they say to install it.

yellowdog

I agree the height listed is a minimum and local code may have a minimum height which is higher, but the configuration of the piping on the outdoor of the house should not vary from the manufacturers instruction. If they list a 90 for a termination, that means you do not use a 45 or a tee. If they don't want a screen on the exhaust, you don't add one just because you want to. I handled warranties for a supply house for years. These are all things that will void warranties if not followed.

hot_rod

That boiler comes with two vent screens, use one on the intake, but don’t glue it in.
I’m not sure what the second one is for?
I also noticed a temperature control on the exhaust if you vent with pvc? Although it come with a CPVC starter piece for higher temperature operation.

Flue temperature run up around 20 degrees warmer than boiler temperature, so the boiler is limited to around 129 degrees when vented with PVC, as I see it.

I have not seen that PVC temperature control before, good to know when you troubleshoot.

Mad Dog_2

I wanna see atleast one support on each pipe...flapping in the breeze. Mad Dog 🐕 

PRR

> That boiler comes with two vent screens, ..... I’m not sure what the second one is for?
I an NOT the maker. But I once pulled a long-rotting squirrel carcass out of a duct. ALL ducts vents etc should be screened. That's about the first thing I did when I ran my air/smoke pipes.

{The Navien manual calls these "birdscreen". I'm sure its the same thing and purpose.}
https://www.navieninc.com/downloads/ncb-h-installation-and-operation-manual-en/download 40MB PDF

Jamie Hall

realliveplumber said:

The manufacturers appliance specific instructions would override local and national codes.

They engineered it and paid to have it listed and labeled. You would install it the way they say to install it.

Not when I was inspecting, years ago. The manufacturer's spec. was always taken into consideration. So was code. Whichever was more restrictive won. If the manufacturer said a foot, and the code says three feet -- it's three feet. If you cared to take the time and effort and get a letter from the manufacturer that said three feet won't work but one foot would, and why, then i might have considered it. But to be slightly brutal about it -- there had better be nothing else out of code on the job...