[dougp23]

I am having this issue on my second floor where the bedrooms are....

The heat piping run is entirely on this floor (save for the feed up and return back to boiler). So each register has the pipe that comes up from the floor, feeds the register, then goes back down into the floor to the next register.

One room is just very noisy, especially when it's cold and it's 2AM, lol. The knocking starts gently, then gets faster and louder and eventually stops. I do not hear anything until the next boiler run. If it was only expansion, wouldn't I hear something as the ppe cools? I have widened up the holes where they come through the floor, but I am thinking it is either under the floorboards, or some sort of pressure bleed thing...

Any ideas?

 

[beenthere]

Turn stat up. Go to room and trace out area noise is worse at. Proceed from there.

 

[how]

Angled pipe straps can often make noice in one direction of expansion but not the return (or vise versa).

 

[jagans]

It has been my understanding that this is caused by improper slope in the pipe which traps air above the hot water. I would say to check the grade on your pipes.

 

[Bondo]

If it was only expansion, wouldn't I hear something as the ppe cools?

Nope,... Not necessarily,... The pipes heat up, 'n expand, Quickly, but cool quite slowly...

 

[dougp23]

Thanks everyone! I will have to open up the floor and see why the pipe is making that much noise. If you are sitting in the room directly below, you can hear it knocking quite loudly as well, so I imagine it must be an expansion issue.

 

[REP]

It has been my understanding that this is caused by improper slope in the pipe which traps air above the hot water. I would say to check the grade on your pipes.

What you are discribing is a STEAM system problem and does not apply to this HOT WATER system