Shower problems

[Nevin]

I have a shower which runs off the combi boiler and which used to work fine. Now however the flow of water is much less than it used to be and is not always sufficient to make the boiler turn on and heat the water up, meaning you have to switch the central heating on as well before you can have a shower. Any suggestions as to what the problem might be?

 

[Ant]

Are all the other hot taps in the house working OK? Check the boiler pressure is high enough (mine is 1.5 bar when cold) I guess this will be OK as you say the CH is working. If the other hot taps give similar problems then chances are the priblem is in the boiler or at least in the common pipework. My boiler (Saunier Duval) has a diaphragm that moves when a tap is opened (sensing the pressure) and fires up the boiler - these regularly fail and the boiler doesn't fire up. Fairly simple to replace and only about £15.
If it is only the shower that is causing problems it may be down to some restriction in the pipe/shower head not allowing sufficient water flow to allow the boiler to fire up.

 

[ogoshi]

If the other taps are ok then remove the hose from the shower and turn it on to see if the flow is ok and the boiler ignites.if it does then it could be shower head blocked with lime or kink in the hose.Also does your shower have filters on the inlets,they could be blocked.
finnaly check that the "flow dial"is actually turning the spindle its mounted on,sometimes they split where it goes over the spindle,resulting in the dial turning perfectly,but the spindle stays put,(most dials pull off ).