Boiler hasn't been on for about 18 months. I now cannot light the pilot light manually. There is 240v at the terminals on the gas valve. The volts disappear when I switch the boiler temperature setting to off. The igniter hasn't worked for some long time, therefore I have lit the pilot light with the temperature control set to 180 degrees, manually whenever the gas supply has been off. This time I have had no success. Any ideas?
John Thompson, December 2016