Big BANG when the pump switches off !

Bob1000 · Mar 16, 2007

I got the following system
0.75HP Booster self priming pump connected to the water mains
Pressure tank ( air pressure 30psi)
Pressure switch st to 44/68 psi
A check valve at the water entrance to the pump
when the pump stops I hear a big bang , very annoying !
Any advice?
Thanks in advance

Speedbump · Mar 16, 2007

Make sure the check valve is the spring loaded type. You may have a swing check that would do the banging out of the box.

bob...

Sponsor · 2022-01-29T12:20:58-0800

Bob1000 · Mar 16, 2007

hi

speedbump said:
Make sure the check valve is the spring loaded type. You may have a swing check that would do the banging out of the box.

bob...

Check valve is the spring loaded one (YORK) 1"

Bob1000 · Mar 16, 2007

valveman said:
Put 40 PSI air in the tank. Replace the check valve. If that doesn't fix the problem you can use a Cycle Stop Valve on the discharge of the pump. The CSV will reduce the flow from the pump to 1 GPM before the pump shuts off. This will keep the check valve from slamming from the wide open position as it is now.

But that phenomena is new , the pump has always been there but we never heard that bang and usually is loud and sometimes not as much !

Raucina · Mar 17, 2007

Your pump is being fed by a pressurized main, 30 or 40 psi [?], so you have a high velocity flow of water to stop instantly.

Perhaps the spring is broken on your check valve and the seat is mislocated.

A Conbraco SS check valve is sold by surplus center for 13$ that closes flawlessly and quickly - it has solved most hammer issues for me with booster pumps.

You might also try a smaller flomatic check valve in 3/4" to restrict the pump feed a bit.

Bob1000 · Mar 24, 2007

No, the incoming mains pressure is almost 25psi
will replcae the check valve and see what will happen
Thanks to all of you

Raucina said:
Your pump is being fed by a pressurized main, 30 or 40 psi
N[?], so you have a high velocity flow of water to stop instantly.

Perhaps the spring is broken on your check valve and the seat is mislocated.

A Conbraco SS check valve is sold by surplus center for 13$ that closes flawlessly and quickly - it has solved most hammer issues for me with booster pumps.

You might also try a smaller flomatic check valve in 3/4" to restrict the pump feed a bit.

Raucina · Mar 25, 2007

The internal design of your checkvalve will be important. Most checkvalves open too wide and create turbulence with a flat closing disc. Look for a valve with a machined interior and a composite plastic round or oval ball.

You can also increase the shut off pressure and restrict the pump outlet slightly to reduce flow velocity of your water at shutoff.

Found the model # 1" Conbraco brass #61-105-01 and SS #62-105-01 34$ and 110$ respectively, but Surplus center has some at 13$ - Go figure. Maybe they are slightly off spec, but I have several in use for years without fail.

"vibration free ball cone check made of TFE"

bigtoewit · Apr 5, 2007

Bangin Check Valve

I have a ejector pit with a pump in my basement floor. The house is only 17 months old. On the line connected to the pump is a check valve/shut off valve combination. When the pump discarges water the check valve slams hard and can be heard throughtout the house. Do I need to replace the combination valve with two seperate ones. One check valve and farther down the pipe a shut off? Thanks for any help. Mike

Speedbump · Apr 5, 2007

Can you send us a picture Mike?

bob...

bigtoewit · Apr 7, 2007

check valve banging

Thanks for the input. As you suggested I am posting photos. This ejector pit is right behind the wall that seperates the bathroom from the ejector pit. I put the shower, toilet and sink in and everything works fine except for this really loud check valve. Also the pit gathers ground water and it causes the pit pump to activate even if I am not using the basement sink etc. Hope the photos help. Thanks a lot Mike.

Raucina · Apr 8, 2007

I see a partially closed valve, not a checkvalve, unless it is incorporated into the lower half of that valve.

bigtoewit · Apr 8, 2007

Yes it is a combination check valve and shut off. Someone suggested closing the shut off a little to reduce pressure. This did not work. It still bangs loudly.

Raucina · Apr 10, 2007

In my sewage pump systems I use Hayward ball check valves. Very reliable and heavy duty. Yours must have a flapper which allows enough reverse flow
for the bang.

I would better support the pipe to a rigid brace. lose the strap.

You can leave the existing valve in, open it all the way and put the check above it.

Big BANG when the pump switches off !

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