Issue with Combi boiler(hot water)

[simers_as]

Hi,

I would be very greatfull if anyone could shed some light on the issue i'm having.
I have just recently started to have a issue with my combi boiler (sime Format 30 HE).
If the boiler is on for the central heating all is well and I am able to get piping hot water out of my taps, but when the boiler is off and i go to turn the hot water on just cold water comes out. The boiler starts to fire up but then after a few seconds it shuts off. I have no idea about boilers but is there a valve or something which should trigger the boiler to switch on when the water for the hot tap starts flowing through it?

Ash

 

[Barry98]

the valve your referring to is your diverter valve it could be sticking or your diaphram may of split, id suggest you get someone into look at it there not straight forward to replace.

 

[GQuigley67]

must be diverter valve if boiler is firing up then cutting out possibly due to overheaating and the high limit stat kicking in, you'll need to get a gas safe engineer in to fix this for you

 

[Zorro]

Does the boiler fire or just try to ignite?

 

[simers_as]

Thanks for your help.

I'm not quite sure, If it does fire up it is for less than 1 or 2 seconds.

 

[Zorro]

i've had very similar problems on halstead boilers and its the pcb

 

[Zorro]

if it was the diaphragm the boiler would not fire

 

[GQuigley67]

but it could be the diverter valve itself, the boiler would fire with the diaphragm but the valve may be jammed in the CH position

 

[Zorro]

very true good sir

 

[GQuigley67]

best getting a registered engineer out to have a look at it

 

[desrob]

could be the high limit stat,thermister