Shower pump cutting out

[HRMan]

I had a pump (Stuart Turner Showermate 1.4 bar twin) installed on a new shower (with thermostatic valve) at the end of last year and it worked for a few months with no problems. For the last few months the pump cuts out after approximately 2 or 3 minutes; but the pump re-starts if the shower valve is turned to cold. After 15 or so minutes the pump works again (but cuts out again after 2 or 3 min).

I've spoken to Stuart Turner and they think it's a problem with the hot water pressure in the system i.e. the cylinder is emptying faster than it is filled up from the cold water tank. This seems plausible given the fact that the pump works again after it has been left for a while (and the cylinder has filled up again) but why did it work for the first few months?

Are there any other things that might have caused the hot water pressure to drop? Blockages in the pipe? Air in the pipes? The fact that I haven't been using my central heating over the summer?

Are there any ways to increase the pressure coming from the cylinder? (I can't increase the height on the cold water tank). Is it possible to fit another pump from the cold water tank to the cylinder?

Grateful for any advice.

 

[g20]

if it was working for months before its unlikely to be the cylinder running out of water, espoecially after nly 2-3 mins, sounds like the pump may be drawing air into the pipe, which is why its still working on cold but not the hot.

Where is the pump positioned in relation to the hot water tank?

 

[HRMan]

The hot water cylinder is positioned about 3 ft of the floor just above the boiler in the kitchen; the hot water is then piped along the top of the kitchen wall for about 10 ft before feeding the pump (which is situated on the floor of the bathroom, under the bath and directly below the shower).

 

[g20]

this isnt really the best positioning for a shower pump, when its above the tank like this its alot more prone to drawing air into the pipe from the hot water cylinder, idealy they should be positioned on the floor next to the hot water tank if you have enough room to do so,

You can try disconecting the hot water inlet to the pump to see if there is any air (have a bucket at the ready though ) an be ready to fix it on again when the water comes out (try same for outlet, then test the shower again) A better option would be to reposition the pump though.

 

[HRMan]

Sorry I wasn't clear. The pump is below the hot water cylinder (though in different rooms). The pump is on the floor and the cylinder is about 3 feet above the pump.

 

[seco services]

how is it connected to the cylinder ?

 

[BGEngineer]

Check your installation against how it should be installed in Salamanders free "Pump Right" installation guide (note the section you want is "Right Pumps" this is their range of shower pumps.
http://www.salamanderpumps.co.uk/Download/instructions.pdf
I just installed the RSP75 to service two showers and couldn't be more impressed with it. I use the guide as gospel and it has never let me down yet. Hope it helps