Thermostatic shower problems

[justinc]

I installed a thermostatic shower as a replacement mixer shower about a month ago. Recently it has started acting up with only the cold coming through and the shower stopping all together if it is turned all the way to hot. I think it has something to do with the hot water not getting past the in build non return Vv. It may be to do with the water pressure differential but it isn't that great as the cold is gravity fed from the cold water tank in the loft and the hot is from the Tank (also gravity fed from the loft). Can any one help as my wife is getting fed up with going downstairs for a shower, cos it has no heating and a non opaque window which our neighbour can look in to?!?

Many thanks J

 

[Meldrew's mate]

Leaving aside the issue of whether your neighbour would want to look at the wife, try removing the shower head and laying the flexible hose (if it's a flexible type) into the shower tray.

Does the flow of hot increase?
Does it gurgle shortly after starting to flow?
If so look at the supply pipework. Can it entrap bubbles from the HW cylinder and cause an air-lock?

MM

 

[justinc]

Unfortunately it isn't a flexible pipe. It could be trapped air as all the hot taps around the house splutter when they start to become warm. When I've disconnected the supply pipes there seems to be a residual pressure in the shower mixer held in by the 2 non return Vv which are in the elbow joints. The supply pipes have 2 gate Vv, can one of these be used to 'throttle back' on the cold water supply as it only seems to be the hot that can't get through?

 

[uknokianut]

Are you sure it has been connected up correctly . ie hot and cold pipe the right way round . check that the hot pipe is connected to the side with the red dot on it. Its an easy mistake to assume that the old one was connected the same way.

 

[Bamber gaspipe]

I installed a thermostatic shower as a replacement mixer shower about a month ago. Recently it has started acting up with only the cold coming through and the shower stopping all together if it is turned all the way to hot. I think it has something to do with the hot water not getting past the in build non return Vv. It may be to do with the water pressure differential but it isn't that great as the cold is gravity fed from the cold water tank in the loft and the hot is from the Tank (also gravity fed from the loft). Can any one help as my wife is getting fed up with going downstairs for a shower, cos it has no heating and a non opaque window which our neighbour can look in to?!?

Many thanks J

Was it cheap? sounds like the inner workings have called it a day or a blockage on the hot supply.

 

[justinc]

Unfortunately it wasn't cheap. When it works it works fine, it is just that 50% of the time only cold water comes out and the flow rate of this can be controlled by the temp control. One thought I've had is to remove the hot not return Vv and put a check Vv further back in the pipe work as when I have disconnected it it seems to be this Vv that is stuck shut with a back pressure behind it. Do you think this will work?