shower pump cuts off when turned to cold

[scottpetrie]

Hi
My shower is a basic 2 pipes coming from wall with a mixer knob in the middle. Lift the lever up to switch on, right to turn up, left to turn down. Recently the temperature has been feeling like its getting hotter, so the knob has had to be turned down whilst at normal showering temperature. This morning it got really hot, so I turned it down, but if I turn it right down to cold, the pump cuts out. Im sure its not a pump fault as its only just over a year since it got replaced. The shower works fine when its hot, but when I trn the knob colder, the pressure gradually decreases, then when the knob is right down to cold it cuts out. Any ideas????
Thanks

 

[Newboy]

Symptoms suggest lack of cold supply / obstruction to cold

Is it a thermostatic shower - if it is then there could be a fault with the cartridge or if not then a blockage in the cold feed such as a blocked filter. Also possible failure of the impeller on the cold side of the shower pump

 

[scottpetrie]

Sorry Im not too clued up on this. Where abouts is the cartridge or the filter? The shower basically has a cold pipe on the right and a hot pipe on the left, with the lever in the middle. Is that thermostatic?

 

[Newboy]

If it's thermostatic then the cartridge will be (usually) behind the temperature control dial. The filters could either be in the pipework leading to the mixer or within the body of the mixer itself.

Can't tell from here type or model - my physic abilities are very limited!

 

[scottpetrie]

It doesnt have a make or model on it Im afraid. I cant see any filters in the pipework coming from the pump & the rest of the pipework is behind the tiled wall. Maybe if I turn off the water supply, & remove the mixer from the wall it may become obvious

 

[ALCPlumbing]

Some pumps only require 0.6l/min to activate the flow switch. If cold water still flows from the outlet and the pump isn't kicking in then it's most likely a pump problem. Either the flow switch on the cold side of the pump has had it or the start capacitor. If it's less than a year old it will be within warranty. Some pumps are two years if registered.

 

[scottpetrie]

I wonder, could it be the cartridge in the actual shower controls that might be blocked, as when I turn it slowly to cold, the pressure decreases as I turn the knob and then when its completely round to cold, it cuts off