will circulator pumps cause water hammer

JOE_99

I'm thinking of installing BB water heat.I plan to have 3 or 4 zones each with its own circulator pump.In between each zone I will have a valve so that if one pump fails I can just open a valve and get heat to that zone.If I just have the pumps will they make a water hammer(WH) sound when they turn on and off.Or should I have zone valves after each pump to stop any WH.

Brad White_9

If you combine zone valves and circulators

you will increase your chances of water hammer.

Water hammer is a function of too much differential pressure and/or too much velocity coming to a stop or restriction. A properly sized circulator and soft-seated flow check valve are your best friends. Well, you still buy the beers but you know what I mean.

If you do use zone valves, the circulator would be sized for all zones then divided by the zone valves. A DP relief valve bypasses any excess flow when any ZV is closed. That is Plan B.

Nick Ciasullo

You can reduce the chance of noise

Use a smaller pump. Since you are zoning out with pumps, don't use B&G NRF-22 or Taco 007 pumps as they are likely too large (or the Grundfos, Armstrong or whatever equivalent). The high head that these pumps generate will probably cause the valve to slam shut. Instead, use an NRF-9 or 005. These pumps are less than half the electrical consumption, and don't generate anywhere near the pressure differential that their big brothers do.

Nick
Representative - ITT B&G

Glenn Sossin_2

Paranoia

Why not just keep an extra circ on the basement shelf?

Installing this valve as you describe will almost certainly create some balancing issues - and your not likely to leave it this way. Your going to go out and buy a replacement circ. Install isolating valves on each circ and it should take just a few minutes to change one out with out even having to repurge everything.