zone valve water hammer

carol_3

Honeywell's 5000 series zone valves are supposed to be water hammer resistent, if you can use straight-through zone valves. So for example a V8043E5012 is a normally closed straight-through power open, spring close 24V zone valve. The 5000 series is indictaed by the digit after the middle letter. The way it works is that it has a sensor in the motor. If it senses that it's closing off against high pressure, it slows the close.

Royboy

here's the situation

a friend is asking me if I can help him eliminate a water hammer noise in his heating system prior to him selling his house. he's lived with the noise but isn't wanting to pass it on to the new owner. I didn't install the heating system and the guy who did has moved out of the area.

configuration is a 1" constant circulation loop from an outdoor wood boiler through his basement. there are two upstairs zones which each have a zone valve on their supply legs (off the constant circ loop). water is forced into them by a normally-open zone valve just downstream from where the supply lines take off. this valve closes when either of the zones open. the zone loops return to the constant circ loop through a common return just beyond the normally-open diverter zone valve.

it is the action of this normally-open diverter zone valve that causes the hammer, which happens as the valve closes. it is controlled by the other zone valve end switches, so it should close only after they open, which I would think would lessen the chance of it hammering - but it does nonetheless. (though I can operate it manually and if I close it slkow enough there is no hammer!)

the "diverter" zone valve is a 1" Flair brand valve - which I'm not familiar with it. it appears that the spring in the motorhead is not reopening the valve much so we're wondering about replacing either the head or the whole valve.

questions:

do you think this layout is inherently problematic?

do you think a different valve here is likely to solve the hammer problem?

we talked of maybe removing the diverter zone valve and replacing it with a ball valve or balancing valve which could be closed to the point of forcing flow through the zone loops when their zone valves open? what do you think of this approach?

the wild card is that my friend thinks the new owners may want to take the wood boiler out of the system and convert it to a pressurized system on a gas boiler. so he's reluctant to do too much of a rebuild, not knowing where they are headed with it ...

thanks - Roy

bob young

banging

check direction of flow. a reversed zone valve will cause water hammer turbulance.