6X6 room gas furnace and hot water tank

[Mark Nicholet]

I inspected a room with 100,000 BTU natural gas furnace and 36,000 BTU hot water tank in a 6X6X8 room. No exterior ventilation for combustion air. Door to room was trimmed at bottom allowing house air to enter for combustion air. I am going to recommend an exterior vent added for combustion air. My question is: There is currently an exterior vent with ducting into the return air plenum. Should I recommend the return air plenum be sealed from exterior vent and exterior vent be allowed to add air into small utility room for combustion air? Thank you.

[cbottger]

Originally Posted by mnicholet

I inspected a room with 100,000 BTU natural gas furnace and 36,000 BTU hot water tank in a 6X6X8 room. No exterior ventilation for combustion air. Door to room was trimmed at bottom allowing house air to enter for combustion air. I am going to recommend an exterior vent added for combustion air. My question is: There is currently an exterior vent with ducting into the return air plenum. Should I recommend the return air plenum be sealed from exterior vent and exterior vent be allowed to add air into small utility room for combustion air? Thank you.

I think I would stay out of the recommendation department as to how to make repairs I would recommend that it does not have proper combustion air provided and let the repair folks decide how to make repairs. Keeps the monkey off of your back. On the personal side if I live north of the border and had a exterior duct to the return air I would leave it as is provided there was a damper that could be sealed off during the winter months. Nice to bring in outside air when cooling or heating is not required.

[Greg Veal]

I agree with Charley, recommend that the lack of adequate combustion air be corrected by a Pro in the field. Hard to believe the original local inspector missed this during the installation process.
You may be dealing with a replacement installation, where the contractor took it upon himself to make some changes. We see that a lot in my area of the country.