Back draft

Water heater was installed in June of 2008, at the BLUE & RED plastic rings around the pipes on top of the water heater are melted, is this a good indication of back drafting? The run on the flue pipe is very long, is this a problem.

Thanks! in advance for your input.

Could be…did you check it with a mirror or gas detector or such?

The connector pipe looks like it runs down hill from the picture.



Mirror did not fog up and my FLUKE CO detector did not detect anything. I agree there is a slight downhill run in the flue pipe. I will refer the whole thing. The TPR valve was also leaking. It might need a thermal expansion tank or valve installed.

Or they melted during the install when sweating the copper. Maybe.

I thought about that also.

Where did the mirror test come from? I know it has been use as a way of testing draft for some time.

I personally use the information from the manufacturer. Wait 15 minutes after the burner turns on and test with a match. If the match has a steady flame as it gets drawn into the opening, it is a proper draft (hard to fight that in court).

So the plastic overheating from back drafting during the first 15 minutes from when the burners turn on can be a possibility. Indirectly, the manufacturer does considered that acceptable.

Is that flue supported properly?

I think you need to expand the photo. Looks as though the vent is not proper but cannot see in the pic. What other issues are going on around the water heater?


I would have turned up the temperature on the W/H and viewed the the draft hood area, while the flame kicked on.