no hot water coming out of our shower we have a combi boiler 24cdi ?

Do you have hot water at your tap if so its the shower mixer

welsh leek
April 2009

is it only the shower that does this, or have you noticed a lack of hot water at any other tap?

Is it a thermostatic mixer shower?

If the answer to these questions is yes just the shower, and yes it's a mixer, you could be looking at something called "cross flow". This is referring to a problem with the shower itself and not with the boiler. This is easily identified and probably needs a plumber to put right.

The other possibility is that the problem is occurring at every tap, and that it IS the boiler's fault. Watch the hot water indicator lamp on the boiler. When you turn on the tap, does the light come on and stay on? If not, there's probably a problem with the diverter valve in the boiler.

Bunslinger
April 2009