ZV hammer vs Grundfos Alpha

Steve_35

Over the years we've solved numerous complaints of ZV, typically HW, hammer by replacing the ZVs with Taco 570 series valves.  I'm wondering if the Grundfos Alpha 15-55 pump would help to solve that issue or would it not react quickly enough help.



I understand how a delta-P pump operates and it seems that it may address the problem, but I don't know how quickly it reacts.  Too slow and you would still have the hammer.



Anyone tried this?

Robert O'Brien

Alpha

No hammer with Alpha pumps,also no hammer with valves on return or with a diff bypass either!

Mark Eatherton

Hydronic Hammer from Hell...

the ONLY time I've seen a Honeywell V8043 series zone valve hammer is when they are installed backwards...



With that said, I don't think the alpha could fix that.. The normal flow path is such that if you are sending too much water through the valve due to an oversized pump, the valve will NOT close off completely. If water is running through the valve backwards, it will suck the ball onto the seat, and THEN it will hammer like the hubs of Hell....



The DEVI'L is in the details :-)



ME

ChasMan

Hammer Bammer Slammer...

I have Caleffi valves, Z One types. I had hammer on one zone and I just installed a pair of Alpha circs. So far so good. I haven't heard any hammer YET. They don't appear to react fast enough to be a cure though, I'll know more when it gets cold and the water gets hot. Thats when it hammers the loudest. I don't think all my zones are coming on at the same time yet either which is when it hammers.

hot_rod

the cause of hammering

Is in the hydraulics of the system. 



 Use flat curve circs with zone valves,size the circ pump to the load properly.  Use a hydro separator if the heat source has a high pressure drop heat exchanger. Check the Cv on the zone valve they come with different size orffices and Cv ratings for specific applications. Use a pressure activated bypass valve when 4 or more zone valves are installed, as a rule of thumb.  Or if a high head circ is used. Install the valves on the return so the piping "scrubs away" some of the head before the valve sees it. These are a few of the ways to solve hammer issues.



The delta P circs are an excellent solution and usually bring along a much lower power consumption, but they are should not be required to rid a system of ghost hammering.  It's all about the velocity you are closing off against.



hr

Steve_35

Thanks

We're looking at a problem job.  Not one of ours.  There are a few ways to rectify the hammering.  Replacing a standard pump with a delta-P pump would be a relatively inexpensive solution while providing the additional benefit of lower electrical usage.



Thanks for the input.