circulation noise

J. Cricket

Good point. In this case there is no indirect.

J. Cricket

circulation noise

We have two zones. Only one is noisy. It's not the circulator; they use the same circ (Grundfos 15-58) and I have tried switching them. It increases with the speed of the circ. It's not a gurgling noise but a constant and quite loud clattering noise. The noise feels like it's worse than it used to be in previous years.

The noise is loudest near the boiler; it can be heard near the radiators upstairs, but very faintly. The noise seems to come from the near-boiler pipes, which are 1" copper, going to cast iron in the rest of the house. As you may have guessed, this zone is a converted gravity zone. There are three parallel branches, but closing off any of the valves doesn't change the noise; only closing all of them stops the noise (bad for the circulator, of course, so I only did it for a couple of seconds).

The other zone (noiseless) is 3/4" copper all the way.

I would be grateful for any suggestions.

Big Ed_4

Flow Valve

Unscrew up to open the flow valve on the supply pipe and see if the noise stops . If its a old Watts air traps in its bonnet and the valve will chatter. Change the valve .

If it is not a Watts , replace the valve with a one size smaller flow valve..

Any old check valves on system ?

J. Cricket

All valves are wide open. I will play with them to see if I can get any clues.

There is a check valve but it's only 5 years old. It could be the problem but I don't know how to test it other than unsoldering and removing it.

Big Ed_4

Check or Flow Valve

A flow valve will have a stem on top to lift the weight. This valve is more suited for heating large volume heating system . Some use a spring loaded check valves which sometimes fall apart . There will be no way to open this type check. A swing check which has no place on your system will have a cap on top with a nut on it's side .

J. Cricket

OK, then I have no flow valves and no swing check. I do have a check valve built into a shutoff valve. No way to test it; maybe in the summer I will unsolder it if nothing else can be the problem.

Many thanks for your help,

Big Ed_4

I never seen a check in a shut off..

I would recommend replacing the spring check with a flow valve . just remember if supply pipe is 1 1/2 or larger drop it down one size....

Unknown

I`ve heard,

the 15-58 or 15-42 chatter sometimes. Usually caused by armature "flutter" within the "can" because of nothing much to push against.
Was the built-in C/V left in or removed?
As Ed suggests, try another check.

Dave

Bob Bona_4

Last week

I did a service call for the same issue. It was the early Taco 007 IFC with the spring check in the volute area. The check dome was chipped slightly, and making a soft chattering. Your check/iso valve most likely uses the same caged spring check assy. That would be my first stop.

J. Cricket

The circ's built-in check valve was removed. In any case it's not the circ, because I have tried switching circs (see first post).

I will take out the installed check valve in the summer.

Why do I need a check valve at all? Except in the bathroom, my radiators have TRVs. And with outdoor reset, the system runs 16-18 hours a day anyway, and if some ghost circulation occurs, that merely keeps the water circulating longer, which is not a problem. Any other reason I would need a check valve? (sorry, I'm an amateur.)

Big Ed_4

May not

TRV will control the overheating and the outdoor reset will shut off the boiler. Only problem I could see is if the boiler heats up the homes hot water like with a indirect. Every time the boiler would heat up your bathroom would heat up.