I have a worcester 240 RSF closed system. I have just taken the bolier off the wall for plastering work and replaced it in the same place (drain sysem etc).
I have noticed that my boiler takes up to 40 seconds to fire up (heating of water). The spark and pilot light comes on immediately but the main heater takes annother 10 to 40 seconds to fire up.

any Ideas?

Booji, September 2008

Hi,

How it works is that the electrode for the spark first ignites the pilot, then if the pilot flame is the correct size it makes contact with the electrode and the flame sensing circuit on the circuit board conducts through the flame which then allows the main burner to operate. If the pilot is not correct or if the ignition lead or pcb is faulty this will prevent the main burner operating.

Ian, September 2008

The igniter does spark after the pilot is on and as soon as the relay operates on the sequence board the main burner comes on. How does the igniter sence the flame? I was looking for a sensor but cant find one. Is there a sensor in the spark ignitor itself such as heating the ignitor changes the resistance. If you could elaborate one the opperation of the ignition unit I would appreciate it.

Booji

Booji

Booji, September 2008

possibly a poor pilot light, if the igniter keeps sparking after the pilot is lit the electrode is not detecting the pilot flame and will not energise the main gas solenoid. May just require the dust blowing out of the pilot assembly or the pilot jet cleaning.

Ian, September 2008