HONEYWELL ZONE VALVE WATER HAMMER

TJK500

I went out to a service call for banging pipes in the house. I found the noise coming from 2 out of the 5 honeywell zone valves. The noise is coming from the 2 zone valves that supply the upstairs part of the house. I believe that there is an issue with the zone valve closing to fast and thus causing this issue. We swapped operators from non noise making valve to noise making valve and there was no change. Any thoughts on this would be helpful.
THANKS

Grallert

Are the noisy valves installed in the correct direction? Closing against the flow?

hot_rod

What type and model circulator? If it is a fixed speed it should have a pressure activated bypass. Often  a ZV hammers when closing against excessive flow.

Ironman

Are there any flow checks in the system? Check valves and zone valves don't go together. Doing so causes part of the system to be isolated from the expansion tank when both are closed. When the ZV opens...bam.

HomerJSmith

I had the same problem with a Honeywell zone valve and I installed a washing machine hose bib water hammer arrestor, it helped.

Someone suggested removing one of the springs on the zone valve to slow the closure of the valve.

I was thinking, maybe the valve closes before the pump turns off. I know that there is momentum in the circuit. The expansion tank can act like a water hammer suppressor.

EdTheHeaterMan

Those Honeywell valves do spring closed pretty fast. And if the valve is in the wrong direction the water flow helps close the valve faster. If you do find that it is backward, consider a slower closing valve since you need to drain the pipes to make the correction.

Just a thought, if the money is there, I know these are difficult times for some.

DanHolohan

Here’s why:
https://heatinghelp.com/systems-help-center/banging-zone-valves/

hot_rod

We put a slow motion camera on a common spring return zone valve to see what happens when it is powered off and spring closes. It can show how and where the hammer can develop.

That spring tension actually winds up in the motor not unlike a flywheel. When the valve closes the paddle or ball inside actually bounces a few times until that spring inertia dissipates. The bounce can start the hammering.

A couple way to engineer out some of those issues. A coil type spring has a smoother "curve". Actually looks like a pump curve.

A common screen door type of spring found on most spring return valves has a lot of pull back force when fully extended, but very little in the close position.

The coil type spring used in the Caleffi is adjusted with a torque meter gives a much more consistent tension from start to wide open. Basically help eliminate the "bounce" The more metal or wraps you put in a spring the more consistent the tension is across it's working range.

A lost motion gear allows the spring tension to disengage from the motor, think of it as pushing in the clutch when you come to a stop with a manual transmission

Removing one spring on a ZV with two, may change that pull back force, and in some cases fix the "bounce" and hammer. It may also change the valves shutoff pressure. So the valve could leak across. The spring tension is what keeps the valve closely closed. I suspect they would not use two springs if one could work. Springs are $$ and when you sell millions of valves it does add up.