I inspected this house today and this is what I found when I looked at the natural gas furnace chimney. As I was inspecting the furnace I noticed a ticking noise which sounded like water pinging the metal. Of course their was plenty of rust in the draft hood and on the burners.
My assessment was that the byproducts were condensing sooner than they should and dripping back down the flue. Just so happens at the end of my inspection an HVAC guys shows up to do a bid for adding AC to the unit. He says the furnace is just fine but very old.
My concern, I didn't question him in front of the Realtor, was that the condensation will rust the heat exchanger from the top. This is an upflow furnace.
Comments please.
-- Steven Ramos
EnviroVue Home Inspection
866-541-2883
Originally Posted By: rsummers This post was automatically imported from our archived forum.
Steven you are correct in your assessment of the flue condensation issue. With gas appliances you need to keep the stack temp hot enough to carry the gas out while its still a gas as it exits the building. If the A/C dude was doing his job he would have caught it and if he said it was not a problem that shows you what he knows. Most manufactures recommend that the temperature rise should be in the top 2/3 of their recommended temps and this will usually keep this from happening. The 025 being used to terminate this flue is not the best choice and may be adding to the problem.