water hammer in a hydronic system??

[Deleted User]

Weil-mclain hot water boiler. 7 zones, mix of baseboard and radiant. All Honeywell zone valves on supply side of boiler, as well as the circulator. When two of the zones close water hammer occurs. Other zone valves were making banging noises and we replaced them, the problem still occured. As well as a bang the system is losing tremendous pressure dropping from 21 lbs hot to about 10lbs. The boiler and all componenets were installed less than 2 years ago. No signs of a leak are present and all radiant is staple up. Theres no air in the system because no heat isnt the symptom its just a loud bang when a zone valve closes and loss of pressure.

[Deleted User]

water hammer in a hydronic system

Weil-mclain hot water boiler. 7 zones, mix of baseboard and radiant. All Honeywell zone valves on supply side of boiler, as well as the circulator. When two of the zones close water hammer occurs. Other zone valves were making banging noises and we replaced them, the problem still occured. As well as a bang the system is losing tremendous pressure dropping from 21 lbs hot to about 10lbs. The boiler and all componenets were installed less than 2 years ago. No signs of a leak are present and all radiant is staple up. Theres no air in the system because no heat isnt the symptom its just a loud bang when a zone valve closes and loss of pressure.

tim smith

Has sound been there since new

I would suspect you have some zone valves in backwards or pump is pumping wrong way. You may want to check this. Tim,
I just noticed another note in your post, is the pump on the boiler side of zone valves or on the outlet side of zone valves?

[Deleted User]

We checked that theyre all right

ed m

is the pump on the return? what size pump?

[Deleted User]

pumps on supply taco 007

tim smith

? sequence of problem

Try turning on all zones and then shut just one off, does it make the sound. Then try one more, any sound? Sounds like you may need a pressure differential bypass installed to take additional head when more than one or 2 valves are closed to stop the excessive pressure on zone valves? just a thought.

Jim Bennett

Banging zone valves...

read this:

http://www.heatinghelp.com/newsletter.cfm?Id=137

Copy and paste,

Jim

Justin Gavin_5

Another Option

Before you install the Diff Bypass valve, Pick the smallest zone and detach the zone valve from the stat and leave the valve forced open. Let the system run for a couple of days. If the noise goes away you know that it is a Differential Pressure problem. This can be fixed by a Diff Pressure valve or a 1/2" bypass line.

dann crist_2

z valves should be on return side--espesialy Honeywell-- try using the slow closing valves--the powerhead fits right on the old body.