Venting/BackDraft on Rheem Water Heater?

Users who are viewing this thread

girafdaniels

Member
Messages
49
Reaction score
4
Points
8
Location
KC
My carbon monoxide detector went off recently, so I had the gas company out to test levels at our only gas appliances -- 38000 BTU Rheem* water heater and 80% efficient 88000 BTU furnace sharing flue venting.

The gas company measured 45 ppm CO at the top of the unit when it was kicked on (and the furnace was not), and there are signs of melting at the plastic caps surrounding the draft hood. As points of note, we’ve had the same set up for 2 years and the CO detector hadn't gone off prior. There don’t appear to be obstructions in the vent ductwork (other than a few mud dauber nests in the chimney) after inspection. When I light a match, the flame is drawn into the draft hood.

The furnace was producing ~10ppm CO, as well, so I'm having that separately diagnosed.

The water heater shares venting with my furnace, and I’m wondering if anything should be changed with that set up? I’ve read that the vertical venting over water heaters should be min 12” before a turn...

The flue chimney is 6” double wall where it turns up from the basement through a chase on the main floor and out of our low slope roof. Approximately 18-20’ height.

* The plumbing supply house, where my Rheem was purchased, processed a replacement water heater for me under its 6 year warranty (which was only a week from expiring). Great guys to work with. They said they hadn't previously encountered such a high reading of CO reading directly out of the top of the unit like that. So, I'll be installing the new Bradford White -- supply house no longer carried Rheem -- 40000 BTU 50Gal tank in its place.

Thanks in advance for any advice and please let me know if I can provide more information that'd be helpful.

IMG_0993.jpg
IMG_0994.jpg
IMG_0996.jpg
IMG_0997.jpg
IMG_0998.jpg
 

Fitter30

Well-Known Member
Messages
2,514
Reaction score
383
Points
83
Location
Peace valley missouri
Minimum slope of a flue is 1/4" per ft. Furnace natural vent or have a vent fan? Can try cutting the ell down to make it shorter will have to lenghten the pipe a little.
 
Last edited:

girafdaniels

Member
Messages
49
Reaction score
4
Points
8
Location
KC
That setup should be fine. I'm not sure what your asking.
Thanks for your thought. I was asking if there's anything problematic with my venting set up. "I’ve read that the vertical venting over water heaters should be min 12” before a turn..." and there's significant CO presenting at the top of the WH.
 

girafdaniels

Member
Messages
49
Reaction score
4
Points
8
Location
KC
Minimum slope of a flue is 1/4" per ft. Furnace natural vent or have a vent fan? Can try cutting the ell down to make it shorter will have to lenghten the pipe a little.
Slope shouldn't be the problem. The furnace is natural vent. To clarify, are you suggesting reducing the bend where it leaves the draft hood?
 

Master Plumber Mark

Sensitivity trainer and plumber of mens souls
Messages
5,368
Reaction score
286
Points
83
Location
indianapolis indiana - land of the free, home of
Website
www.weilhammerplumbing.com
If you are getting a bradford white , you might want to see if you can get your hands on a 50 gallon low boy gas hot water heater --just pay the extra money for it...

With a shorter unit you will have at least close to a foot of extra SLOPE draft upwards from the heater...
this might help solve the problem..... maybe , but it wont hurt either
 
Top
Hey, wait a minute.

This is awkward, but...

It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.

If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.
I've Disabled AdBlock    No Thanks