Check valve question...........................(Starch)

John Starcher_4

.....a hot water system for a church. Three zones, each with independent circulators that are controlled by thermostats. This is an older system that has been retrofitted at some point - the supply pipes are 3", reduced down to 1 1/2" for each circulator.

I replaced one of the (oversized) Series 60 circs with a smaller Armstrong E13. Did this because of a pump failure, and had to get the heat on ASAP. The E13 has less capacity than the existing B & G pump, but it's heating just fine. This tells me that the original pump was oversized. Most of the piping is concealed, so it will be extremely tough to calculate actual head of each loop.

Here's the problem: Each of the existing loops has a 1 1/2" spring check valve installed immediately downstream of the circulator. They appear to be standard type valves. I don't know if someone makes a spring check specifically for hydronic systems or not. The check valves chatter pretty bad, and it's worse when more than one pump is running.

I'd like to eliminate these check valves, and install swing checks on the returns instead. Each return is 1" copper where it enters the boiler room, and there is sufficient horizontal run on each line to mount the valves. My concern is the potential noise if the swing check "slams" shut when the circ turns off. I have used swing checks before, usually downstream of the circulator, and have not really had any noise problems.

I'm thinking that this configuration will not cause excessive banging, but would hate to find out the hard way!

Any thoughts??????


Starch

bob young

flow control

why not consider flow control valves? what could work better

Sweet_2

Another thread posted

the other day "swing check vs. flow check". addresses this same topic .

Andy Stack_2

Check Valves



Viega has a spring check 1/2" to 1-1/2" that I have
used for years with great success.

hr

To operate properly

a check valve really needs to be sized to the flow rate, not the pipe size. Most times a pipe size check valve is oversized and hense the chatter.

In your case you don't really know what the flow rate SHOULD be. You could add up the BTU requirement of the emitters on each pumped zone and ballpark some pipe length and fittings and get real close. You'd really like the GPM and pressure drop of that circuit to correctly size the circ. You might add a circuit setter to get some readings and have some adjustability.

You're kinda starting in the middle and working both ways .

Becareful with any flow restricting valves near the suction side of a circ, especially a high head version. It may be enough to coax that baby into a State of Cavitation

hot rod

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