Power Shower problem

[Jerry1]

I have a power shower with a salamander pump. The pump has two inlets one from hot water tank and one from cold water tank, and has two outlets going to shower unit.

When the hot water is used in the kitchen and the tap is switched off suddenly, the pump turns on and off constantly - the only way to stop it is turn the shower on then off.

What i think is happening is a mini shock wave is created when the tap is switched off and this travels up the pipe to the pump flow sensor/diaphragm and turns it on. the water in the pump has nowhere to go (because the shower is off) and so a back pressure builds up and presses against the off sensor/diaphragm this mini cycle repeats itself constantly until the shower is turned on to release the pressure.

What i would like to know is how can this be stopped, is there a way to alter the sensitivity of the flow sensor?
or is the above theory rubbish and something more simple is occurring

suggestions would be much appreciated

 

[chrishutt]

I think your theory is more or less correct, although the flow sensors might not be diaphragms. A possible solution is to put a small pressure vessel or shock arrestor like this one from BES on the hot pipe (near the kitchen tap or shower pump outlet?) to absorb the shock wave.

 

[Jerry1]

thanks will look into it