Orifice Plate/TRV Installation Troubleshooting

mgeraci

Hello! We recently installed orifice plates and TRVs in a large building and all seems well except we're getting some complaints of pipe banging from a few apartments in the building. One resident gets a fairly persistent "tink" sound in the walls, I imagine this is coming from steam in the return line, but I suppose it could also be the riser. Another mentioned that their radiator is "ticking" even when they valve it off. Can anyone offer any suggestions as to how to best troubleshoot pipe banging related to orifice/TRVs? Thanks!

Jamie Hall

The first thing to do is to clearly differentiate between a pipe -- or radiator -- banging from water hammer, and one banging from expansion (or contraction). To the anxious tenant, both are dreadful and cause for alarm! But the causes are totally different -- and so are the potential fixes.

A tink or ticking sounds to me -- not being there -- much more like expansion noise than like a hammer, however.

If the tink is actually steam in a return line, the return will be warm or hot (it may be no more than quite warm, by the time it gets to the basement) -- and, if you are depending on orifice plates rather than traps, the solution to that is simply a smaller orifice (assuming that your pressure is under control, of course).

Otherwise -- and for the ticking radiator -- if it really is expansion or contraction -- you need to start looking for anywhere that the movement of the pipes or the radiator itself is restricted, and either relieving the restriction (for example, if the pipes come up through the floor, are they rubbing on the floor? Can you shift the radiator slightly to eliminate that?) or putting a slippery shim in (I've found shims cut from plastic milk jugs can work wonders under the feet of radiators, for instance). One minor caution: if the radiator in question has tension rods, unless they are actually loose (you can wiggle them easily), resist the temptation to tighten them. They break easily...

JUGHNE

Is your steam pressure remaining within the design parameters of your orifice sizing?
Were orifices done because of failing rad traps?
And were all rad valves done.

Between the orifices and TRV's there should be no steam in returns from the radiators.
How about some EOM F&T's or drip traps that may be passing steam.

mgeraci

Jamie - Thanks for the detailed response! I will definitely have to look into whether or not it's a pipe rubbing issue. This could be the issue. I will also confirm that there isn't steam getting in the returns.

Jughne - Steam pressure is within the design parameters. Orifices were installed because of many failed traps. We believe all radiators were done, however it's a bit of a complicated building, so it's possible a few were missed. All F&T's were tested working or replaced recently.

JUGHNE

Possibly you "fixed" traps that were passing steam and no longer have actual hammer.
So if system is quieter then maybe the tings and pings are now obvious.
Throttling with TRV's may cycle rads now and produce more heat up and cool down noises.

Just a WAG.