Banging Wirsbo telestats on shutdown

Rocky

Any one else getting this lately? As telestat goes to shut down, you get hammer in line. Usually a larger pump, (grundfos 26-64 etc). Have gone to replacing the motorized telestats with the thermopile style. Slower acting so you don' get the valve being hammered by pump flow. What are you guys doing for this?
Rocky

tim from Reed Wright

banging telestats

Sounds like you have the telestats on the supply side. I dont usually find any problem when there on the correct side of the system

Dave Holdorf

Pressure bypass

valves will work, especially when using large pumps like the 26-64.

Another quick trick if available, have an extra port on the manifold not connected to any radiant floor loops, just a 3 foot piece of pipe connected from supply to return and the valves slightly cracked open. It will allow a small amount of flow and bypass the pressure to allow proper operation of the telestats;

Or move the telestats to the return side of the manifold.

hot_rod

Need a PAB

with that much pump. (pressure activated bypass) It will cure the banging and allow better flow under small loads (one or two zones calling) Properly adjusted it is always bypassing some flow when zones start closing off.

Keeps the velocity noise down. Danfoss, Oventhrop, and Honeywell have them available. Most radiant manufactures have them in their catalogs, RTI does.

Standard equipment on the Danfoss ZCP zone panels.

The link below helps explain the mechanics better.


http://www.pmmag.com/CDA/ArticleInformation/features/BNP__Features__Item/0,2379,29498,00.html


hot rod

[Deleted User]

I'd bet a dozen donuts....

that this manifold is piped bass ackwards. In all my years, I've only seen one Wirsbo manifold hammer, and it had its supply and return line flip flopped somewhere between the mechanical room and the manifold. UN-floppped them in the mechanical room and noise went away. Check delta T with zone running and tell us what you find.

PAB's are still a good idea, especially when you have a pump with large cajones like you have. It keeps exces velocity noise probelms to a minimum.

ME