(no hot flow to) mixer shower

[Newby2]

Hi

I am having my upstairs bathroom changed. When the plumber took out the old bath tub and washing basin yesterday, he turned off the mains stopcock and the hot water valve in the airing cupboard (connecting the water tank in the loft and the hot water cylinder). Later on he turned the valve back on. However we later found out there is no hot water from the mixer shower (using the hot water from the cylinder) in our bedroom on-suite, only cold water coming out. But all the hot water taps in the house work ok and the hot water pipes in the airing cupboard is indeed warm/hot.

What could be the problem causing the hot water failing to reach the shower? The plumber does not have a clear clue, he guesses there may be trapped air in the pipe leading to the shower. Is this diagnosis correct? Then what is the best way to remove air?

Many thanks.

 

[seco services]

sounds like an airlock.
is the hot pipe for the shower fed of a seperate pipe from the cylinder ?
ie a surrey flange etc.

you can try turn the shower to fully hot and use cold mains to push airlock out or has the pipework any bleed valves?
or slacken a pipe to release the airlock.
or lower the hose from shower and remove the head.

there is a few ways it can be done.