pumped shower too cold!

[garrytheob]

I have a pumped shower fed from tank and cylinder with a warix flange on the cylinder. It is thermostatically controlled but won't get hot enough. Sometimes sounds like the pump is pumping air but I think hot water is getting to the mixer because the feed into it gets hot and if i fiddle with the controls the water gets warm for a few seconds but then turns icy. Could the thermostat need adjusting? If so how? Could the hot water be too hot and be cut off by the thermostat? Sorry if thats a stupid idea but it's driving me mad! Any suggestions would be appreciated. Thanks for reading

 

[JohnD]

see if the thermostatic shower has the hot water connected to the cold inlet.

also see if it has an "overtemperature" control

also see how much water your hot cylinder can provide (maybe less than the pump is trying to suck) and if the hot and cold supplies to the pump are both at the same pressure (drawn from the same tank through similar-sized pipes)

 

[garrytheob]

I'm 99 percent sure the feeds are connected the right way round. Hot usually on the left as you look at it? There's plenty of hot water at the taps so i assume cylinder has enough capacity. What is an over-temperature control? Is that the button to turn it past 38 degrees? Thanks for the quick reply