Water Hammer/Zone Valves

Unknown

A previous version of a manifold we used had loop actuators on it, on the supply side.

I've seen mechanical actuators cause water hammer in that position before, but these are the slow acting thermal actuators. I've never seen that.

Has anyone else ever had water hammer with thermal actuators? If so, how did you fix it?

Brad White

DP bypass?

It seems so counter to what one would expect, Rob, but then, it is the same seating principle so I wonder why we do not see it more often as the valves have to touch bottom at some point. Wonder if a DP bypass valve would help?

Tough to set as the hammer is more of a vibration, washer-to-seat. The relief path would have to be of an equally responsive characteristic. How about a hydraulic shock absorber or bank of them as a buffer.

Is the circulator of a particularly high-head selection? A 26-99 maybe? Not a lot of wiggle room at low loads.

Just throwing out ideas. Have not experienced that condition before.

Unknown

bypass is present, and even turning the Differential pressure down doesn't make it go away.. very strange. shock absorbing is one possible solution, but I'd rather figure out the issue rather than treat the symptom (if possible!).

very odd, but thanks for trying brad!

J.C.A._3

Rob,

Dumb (but often overlooked) question....Do these valves have an arrow pointing in the right direction?

The only ones I've had make noise like that were inherited...and installed backwards.

Could the BDV have a broken spring/setter? Just thinking...Chris

tim smith

Flow direction & water hammer

Rob, is the flow direction wrong for the manifold. If it is then the actuators still won't prevent water hammer in valve assy as it is opening and closing because the valve assembly is spring loaded and still can bounce up and down. Tim

Mark Eatherton

Hammer time...

I'd bet a bucket of Rocky Mountain Oysters (MMMMmmmooo) that the flow is going through the manifold backards...

It happens...

If'n it WEREN'T backards, it would be closing off AGAINST flow, and that will not cause a hammer, especially with a slow acting operator. Only being SUCKED into the seated position will cause it to hammer. BLAM,BLAM,BLAM versus SSSSSSSsssssss.......

Had a customer who's hubby did their RFH, DIY style. He somehow got his main supply crossed up with his main return lines in the mechanical room. After he passed away, she called me up there to talk to me about the system. Whilst sitting at her living room table, there was a sudden BLAM BLAM BLAM (zone valve hammer), in her sweetest Swiss voice she said, "Is that a normal sound???" Sounded kind of like a truck running into the side of the house... No Ma'am, that is NOT a normal sound... :Vell, my dear departed husband said it WAS a normal sound, so we LIVED with it for 20 years..., can you make it go away???"

Funny what people will put up with for the sake of warm floors...

ME

ME

JK_3

just a thought

I agree . ckeck tho flow first. but if the flow is correct i would check the actuators. i had one recently that kept spinning and as it closed quitely against the flow it open fast enough with the flow that it would bang in the first fitting.

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Unknown

flow is correct, though the manifold is constructed with the actuators on the supply (not the return) in this case, we did a lot of projects with the exact same configuration without these problems so I'm leery of it. However, we are going to switch it out with a newer one that has actuators on the return manifold to see if that makes the issue disappear.

JK, sounds like you were getting hammer on zone open? we're getting it on zone close.

Thanks everyone for your input!

[Deleted User]

Curious...

Who's bright idea was it to put the control valves on the supply side of things? Every manifold control valve I've ever seen is a seat/needle type of valve (normally open) and when it closes, the needle pushes against flow.

Additionaly, why WOULD one want the operators on the supply side of the system where they will see higher temperatures, and a shorter life expectancy and would be much harder to gain access to for service/replacement?

THese manufacturers SHOULD ask US about things like this before they make major changes...

Inquiring minds want to know...

ME

Unknown

This is last generation Mr. Pex hardware; there is no problem with servicing, but I agree it was a strange decision originally. The new hardware does not have that issue, actuators are on the return.

Thing is, we have quite a few of those older ones out in the field and no other hammer issues, strange decision or not, this is a very unusual issue for this particular family of components.

Unknown

flow is correct, and PBV seems ok but we're giving it a more robust test to be sure. That's about the only other thing I could think of.

Has anyone EVER had a noise issue related to a malfunctioning expansion tank? Just curious.

Mark Eatherton

I see... said the blind man

as he walked into the wall...

I guess people do make mistakes.

ME