TRV's create water hammer

Woody

trv's do cause water hammer. read dans book.

Neil Gadabury

TRV's creating water hammer

We installed trv's on all the radiators in an apartment building. It is a two pipe steam system. Several of the radiator traps were replaced after the installation with no change in condition. The water hammer is vary loud with tennants who have been in the building for up to 20 years complaining about the noise. We have been able to find only one end of main steam pipe to two basement radiatiors and it does not have a trap but is piped directly into the condensate returns which are under the floor and the receiver tank is in a pit below the floor. Only one condensate return pipe is exposed above the floor near the receiver tank. A pump is used to deliver the condensate to the boiler. The receiver tank is vented. The hammer occures on startup and happens throughout the building.

What new condition are the trv's creating that didn't exist with the old radiatior valves and how do I solve it?

Dan Peel

Flow direction

I'm not a steamer, but, with TRVs in a water setup the direction of flow must be as indicated on the valve. Sticking them in backwards will make them turn off hard and noisy. Worth a look, Dan

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"

Steamhead

You probably have vacuum forming in the rads

when a TRV closes. This can pull steam from the dry return (which is probably caused by bad traps, there isn't supposed to be steam in the dry return) back into the rad, causing banging and wrecking the trap.

You may end up installing a vacuum breaker on each radiator to cure this.

There should not be any connection between a steam line and the condensate receiver except thru a trap. However, the return lines can go directly into the receiver since they have traps discharging into them.

To Learn More About This Contractor, Click Here to Visit Their Ad in "Find A Contractor"