Girafdaniels
Member
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.
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.
