Pressure tank bang

[lenharvey]

I reside abroad and my house is a 4- story unit situated on a fairly steep incline. City water delivery is limited to 2/3 times a week and often the pressure is low. I therefore have two underground storage cisterns and an above ground dual storage tank.

The system is plumbed to enable house servicing from either the city source, the cisterns or the storage tanks.

Previously a locally manufactured bladderless pressure tank was the only thing available and worked but required frequent draining due to displacement of the air pocket by water. I recently was able to purchase bladder pressure tanks and have installed them according to the installation instructions provided by the tank manufacturer, Pentair. The 2 cistern systems work great but I have a slight problem with the storage tank system. All works normal except for a loud BANG at pressure cut out.

The only difference between the systems is that the water is pumped upwards from the cisterns and downwards from the storage tanks. With pump the off, pressure from the weight if the water in the storage tanks is 25psi.

Each system is comprised of the following:
LOWARA 1 hp pump
PUMPTROL pressure switch 30/50
WELLMATE WM0075 (75liter) pressure tank

Is there a magical cure or do I elevate the pump inlet line above the tank water level?

Thanks, lenharvey

 

[Valveman]

Do you have a flapper style check valve or a spring loaded one? A little delay in closing of this check valve will cause the "bang" on pump shut off. Probably need a new spring loaded check valve.

 

[Sponsor]

 

[lenharvey]

Thanks for your input. I'm using a flapper type check valve. I'll install a spring
loaded valve and let you know the outcome.

lenharvey

 

[lenharvey]

Flapper type check valve replaced with spring loaded valve. "BANG" is now a mere "click". Thanks ever so much.