Shower won't turn on / no water flow

[lynnoakwood]

We've just bought a shower pod from Coram with a bar mixer

Odd thing is, when we turn on the flow valve nothing comes out until we fiddle with the heat control on the other side. Even then it takes ages for the flow to start and we have to turn it to and fro several times

Our plumber put an auto valve on the hot tank, thinking the pipe was taking in air and had an air block, but that's not fixed it either and we think he's a bit puzzled himself too

Can anyone tell us what's wrong??

 

[petej]

Could be a lot of things.
Do you have enough head of water above the spray head ? (vertical distance from top of water in tank to spray head)
If possible try lowering the spray head to the bottom of the cubical this will increase the head of water, if this works that's your problem.

Is the shower suitable for a tank fed system ?
Some are only for unvented systems.

Are the hot and cold pipes plumbed the correct way around ?

Do you have a good supply of water to both sides of the shower ?
Best checked without valve fitted.

Go through the instructions that came with the shower valve and check it is suitable for your installation.