I'm looking to purchase a home that has a hot water system. This home shows black marks above the radiators on the painted walls. What does this mean and should I be concerned? The previous owner was a smoker could it be residue or is it another more serious problem?

  • Welcome to the site Ron. Please take a look at the tour to get an idea of how the site works. The "Title" of the question should be a summary of the question rather than your name. I'll make an edit to update that. – JPhi1618 Feb 22 '19 at 23:03
  • And, we'd need more info (e.g. pictures) before we can really help you. – Daniel Griscom Feb 23 '19 at 0:21
  • maybe you can ask the home inspector to determine the source of the marks – jsotola Feb 23 '19 at 3:10

Can you post pictures? Are the radiators for sure hot water or could they be steam?

Sometimes in homes with heavy smokers, the air flow patterns over the radiator fins are so consistent that the smoke residue collects in those places where the air passes over the exact same spots on the walls for years on end. I've never seen black though, it's usually just a brownish discoloration. Black implies soot. Hot water can't get hot enough to make soot, but steam can and that would indicate a serious problem.

| improve this answer | |

Heat rises and dust goes with it. Dust gets deposited in vertical lines above the radiators over yeas. I see it often in houses where the occupants are, less than, let's say, tidy. No offense but hot water boilers can definitely make soot with any fuel but oil fired takes the cake. Anything burning fuel rich will make soot. Soot is just unburnt carbon from incomplete combustion.

| improve this answer | |
  • I don't know why anyone would give a down vote to @Joe Fata when his answer is correct unless you feel that the 2nd statement about the soot is that the soot is what is being deposited on the walls. That is not what he said. Dark spots above radiators are the result of a dirty home. – d.george Feb 23 '19 at 11:15
  • Since I wasn't allowed to edit my last statement , let me add a comment here. I get so disgusted by up votes and down votes that make no sense. I see up votes on statements that are wrong or make no sense and down votes on statements that are 100% correct.Who does this voting and why? – d.george Feb 23 '19 at 11:26
  • @d.george I'm from Toronto Canada and have been in the HVAC business for my entire life, and I mean Dad would take us to work instead of calling a babysitter, kind of entire life. I'm approaching 40 now and I can count on one hand with 3 fingers missing how many times I've seen steam boilers in residential applications. It seems common stateside. Do you still encounter it in resi? – Joe Fala Feb 23 '19 at 14:53
  • Steam boilers were very common in the older neighborhoods where I am from. Many have been replaced or converted to hot water heating since hot water is easier to control, much cheaper and probably safer to operate. The only difference between a steam boiler and a hot water boiler is the controls and a hot water boiler is completely flooded and a steam boiler is not. Most cast iron hot water boilers carry a 20 year warranty on the boiler sections and the same boiler used as a steam boiler had a 1 year warranty. I am a lover of steam but I prefer hot water for a residence. – d.george Feb 23 '19 at 15:47

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.