Thread: Ice on Chimney

Hello all

On arrival I noticed ice on and around chimney.
After checking the gas fired appliances I had byproduct spillage at the hot water heater. The attic access was sealed.(Some byproducts could be seen leaving the chimney) but not as strong as surrounding chimneys.
Any thoughts on the iceing (Temp-24 degrees outside)

Thanks

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Originally Posted by Donald Hobson

Hello all

On arrival I noticed ice on and around chimney.
After checking the gas fired appliances I had byproduct spillage at the hot water heater. The attic access was sealed.(Some byproducts could be seen leaving the chimney) but not as strong as surrounding chimneys.
Any thoughts on the iceing (Temp-24 degrees outside)

Thanks

My SWAG would be bird nest in the flue or cap.

I'd agree with Vern there may be some sort of blockage. The other option could be that the pipe is rusted out under the ice and that's causing a condensation issue at that point.
Under those circumstances my report would recommend the Buyer ask the Seller to provide attic crawl access to determine conditions. It's one of those things that could be an easy repair or add up to real money.
I tend to be suspicious when there is no attic access or a previous opening has been sealed off. A homeowner should have access to assess conditions periodically.

Thanks, I should have access to the attic today

First of all, this is B-vent and not a "chimney". Second, what are the inputs of the attached appliances and do they both have draft hoods? What is the Rh% in the CAZ? Furnace delta T? Does the furnace have a post-purge and if so, how long? Has a certified pro performed combustion analysis and is there a paper print out of the results?

If it is spilling at the water heater both should be shut off and red tagged. Yes, the entire vent needs to be inspected. I am replacing a B-vent today. In the basement, the single walled vent connectors manifold into a 5" B-vent. The problem is, the rest of the vent is 6" B-vent. When I pulled the tee cap and shined my light up the vent, I could see the first joint 4ft up mangled. They stuffed 5" into 6" where it joins in a wall cavity.

Sometimes the exhaust condenses and drips off of the cap which then freezes and forms a sort of ice "stalagmite" where the condensation lands.

Still, get the vent inspected because of the spillage.