Expansion noise or water hammer?

Abracadabra

Can't find any clues that would indicate water hammer, I'm inclined to think this is expansion noise. I've been there 3 times during the day, manually started a run cycle on the boiler, I get no noise whatsoever. Customer says it only happens in the middle of the night after a setback. Setback is only 4 degrees. 68 at night from 72 during day.

https://www.youtube.com/watch?v=xJJHnhfM-r4

nicholas bonham-carter

Tell him to have no setback for a while-68 degrees constant setting, and I am sure they will feel comfortable. Even 65 would work.--NBC

Abracadabra

Heh.. "customer" is the owner of the rental. video was taken by the tenant. I know for a fact that tenants in chicago don't appreciate 65 or even 68. I'll tell him to try no setback at 72 and see what happens. thx.

nicholas bonham-carter

Even though 65 seems chilly, the "feels like" temperature seems higher due to the radiant heat coming from the rads (assuming no drafty windows!).--NBC

Fred

Definitely doesn't sound like water hammer. Is that inlet pipe up against the flooring? If so, as a test, try cutting a strip of plastic milk carton around that pipe (between itand the flooring) and see if the noise goes away.

Chris_L

Sounds like expansion noise. I'd try putting the plastic milk carton shims under each leg of the radiator. I put two shims under each leg of my radiators so they can easily slide past each other, and it has It worked great for reducing expansion and contraction noises.

Abracadabra

Yeah.. didn't seem like water hammer, I couldn't really decide what it was tho... Ah.. good idea on the milk carton thing.... saw the plastic milk carton idea last week. I think I'll try that.. thanks!

ChrisJ

I like the plastic milk bottle bushing.
I agree with others, sounds like the pipe is rubbing against the floor. Can you look down around the pipe with a flashlight and see if it's rubbing on one side? if so just slide the radiator over to get the pipe off of the wood.