salamander RHB140 will not turn off

[sament]

pump used to increase pressure in system and comes on when you turn tap on. will not go off unless you flick tap close to pump on and off. otherwise working normally. what is problem and can it be fixed or is it cheaper to replace unit. it is about 5 years old and has done this occasionally in past but now always.
thx
sam

 

[Technotim]

RHP 140 http://www.salamander-pumps.com/rhp140-twin-whole-house-pump.html is a positive head pump, so if you have not had any new items installed on your system it will be either sticking flow switches which are located in the outlet side of the pump, remove outlet hose there will be a plastic cross section holding the float in place remove this then take out float inspect clean and replace.
The other reason could be you have a thermostatic dual control shower valve that has its Non return valves sticking, just remove and inspect.

The way to tell which it is is to turn off the isolation valve on the hot side of the pump if the pump stops dead then it will be the shower that is at fault. if the pump continues to run then it will be flow switch in pump.

 

[sament]

thx - will try. nothing new. we have 2 power showers from hot water cylinder one of which does not turn pump off.
sam

 

[Technotim]

I would have thought that it is down to one of the showers then, if the pump turns off with other items, it is working!

 

[sament]

thx - also most downstairs taps do not put it off. will check outlet valves first
sam