Boiler pilot o.k, but boiler will not light?

I have a Gas central heating boiler, the pilot light is on , but the boiler will not light, so no hot water or rads....any help appreciated before I take out a 2nd mortgage and call the engineer out!.....Kev.
Kev., September 2004


done
got no hot water or heating

jean garratt, May 2010
i can hear it come on but it not lighting so that the water is cold so is the rads

jean garratt, May 2010
hi my boiler will not light and my water is cold and rads are cold can you tell me what i can do next

jean, May 2010
the actual problem is with the pressure switch, if you remove the cover then locate pressure switch, normally round with 1 or 2 rubber tubes connected, try just tapping it first ,if not then detatch tubes & blow through them to see if they are clear. pr sw clicks which activates burner.remember to isolate boiler before doing this.

gary, March 2008
The common problem is the Thermocouple. It may not be measuring the temperature of the water in the heat exchanger and hence the thermostat does not open the gas valve to ignite the main burners. Its worth checking the Thermostat is commanding the gas valve to open. This is sometimes an electrical solenoid so you need to be handy with an electrical meter.

John

John Stokes, March 2005
Need a bit more info is it a combi or a normal sytem with a cylinder and tanks , can you here the pump running ????

Steve, September 2004