Humming in a steam system

cunninghamzach

hearing a lot of humming, not banging, coming from my grandmothers 3 family house. I can not locate which boiler is making the noise, it is noticeable from outside even when standing in the street. What could it be

Jamie Hall

This will probably a slightly tedious process of elimination — with no preconceptions. First, turn all the boilers (what are the multiple boilers? Why?) off. Humming stops? It may be related to one of the boielrs. Otherwise, its' not a boiler. Now fire up just one boiler at a time and let it come up to temperature. Does one of them hum, but not the others/ Start looking at that one. If they all hum, even to varying degrees, again, it's not a boiler — though it may be related.

One thing to check — although it's not usually audible outside the house — is if these are oil fired and any of the oil feed lines is touching, never mind tied to, other plumbing, that can cause a big hum.