hi just replaced heating cotrols ie, programer,room stat,cylinderstat used a salus/glowworm controls and wiring centre . i have a cable spare / two wires red &black the black as ared tag on it when the controls ask for heat the pump kicks in and the fan. but the boiler wont fire up. checked at the boiler end and the connector block you have the mains feed going in and the other two wires going to the terminal block . the block is as follows L/N/E mains and the HW/CH/CHOFFand then ON and pump L/N/E the red wire goes to the terminal marked ON and the black/red tag goes to the terminal marked PUMP Live. when i disconnected it im almost sure the black/red tag linked with the frost/stat SL in the old junction box , not sure about were to put them in the wiring centre my boiler is a myson apollo 40s , the boiler worked fine until i changed the wiring box cheers dave.

dave m, March 2007

does the apollo 40 balanced flue have pump overrun

paul, January 2009

need to know what system, y plan s plan? if you have wired it
up correctly,probably a fan switch or gas valve fault. manually open any valves and put a temp supply direct to blr switch live and perm live. switch it on for a second,if it fires up.... then your blrs ok and your wirings wrong

jon le gas, April 2007

These boiler have a permanet live to them which allows the pump to run on to clear excess heat when a time period ends this stops the boiler overheating if the permant live is not connected the boiler will not run .sorry cannot be more precise without seeing a diagram of your connection or knowing exactly what controls you have

steve@thermagasplc.com, March 2007