The hot water works fine - the boiler fires up when it is set to hot water, but when set to central heating, the boiler fails to fire. The pilot light is working fine. Any clues?

Rob Gardiner, October 2010

I am also struggling with my Glow Worm. House gets down to 10'C and the system does not switch on when the timer is over ridden to 24H. Tried adjusting the Frost Stat in the garage, and the boiler fired up for a while and then cut out. Got advice to adjust the frost stat with the arrow pointing up, and the room thermo and the boiler thermo at full tilt and the system has fired up. I have flushed the system more than 20 times and there is still gunk coming out. Will continue to flush and adjust all settings but I think I am getting it right.

1.) Flush system - check the equaliser tank, unbelievable amount of gunk in that. Put in flushing liquid
2.) Bleed system - remember the pump.
3.) Turn the pump to max wattage and run for a week with all radiators fully open
4.) Flush again until water runs clear
5.) Clean Glow worm unit - I used a vacuum cleaner.
6.) Run system and put central heating maintenance fluid
4.) Adjust frost stat to arrow facing up ( if there is one )
5.) Adjust Glow Worm to maximum setting - turn anti clock when house is at comfortable temp so unit switches off.
6.) Adjust room thermo to +/- 22'

Fester, December 2010

If it is a fully pumped system, check the diverter valve after making sure the room stat is turned up, if it is gravity, check the pump is operational.

Carefree, October 2010