"Neil" wrote in message
...
Swiftflow 100 died today. Main burner not firing on either DHW or CH.
Pilot
+ fan + pump running fine. I havent got the installers instructions that
would allow me to work through the flowchart that Hepworth thoughtfully
include. Before shelling out 115 for a new Gas Valve are there any
overheat
or flow sensors that would prevent the gas valve operating on both HW & CH
?

Neil



Check the wiring first. You find a one has detached itself or broken. You
say the pilot flame is still lit, so this would indicate that the
thermocouple is still OK. So check the motorised valves, especially the
micro-switches, are making and breaking their circuits correctly, and that
all the thermostats are working properly.

If a valve or thermostat isn't calling for heat correctly, then the boiler
will not fire up when it should.