Halstead Sime trio won't fire up

[Plumbgjc]

Hi I'm a registered gas safe engineer, about 3weeks ago I changed a diaphragm on a diverter valve in a Halstead sime trio due to no dhw, worked perfectly! Now I've been called back to property as boiler won't fire up! It goes through the start up sequence but never fires! There's gas upto the valve at correct pressure! I'm think the gas valve has gone, but I ve heard that there's a switch that goes on these which could cause this problem! Any ideas as the gas valve is nearly £300 for this and prob not worth changing...would like to save the customer some cash! Any help would be great! Cheers

 

[mypetearthling]

This one's better off in the Combustion Chamber,
You'll need you gas safe number to get in, contact mods with it and they'll give you access.

K

 

[Plumbgjc]

Cheers just put in request, didn't know about that!