Glow worm 30ci, When heating is on the pressure goes up to 3 bar?

Glow-worm 30ci
when the heating is on the pressure goes upto 3 bar, and then when its cold it goes back down to 1 bar. I have looked on the internet and it sounds like the pressure in the heat exchanger might be low, but i cant see when to check/add air to the exchanger. Help please
Andy Groves, September 2006


done
Get rid of the Glow worm and buy a worcester

Daniel, December 2008
firstly possible exspansion vessel needs charging or is faulty, second possible fault discharge safty pipe may not be funtioning. You need to get engineer to look at it, NOT D.I.Y FIX-TELE NUM 07788484855.

chris, November 2008
pressure vessel faulty poss repressurise or renew vessel

paul, September 2006
link Click here to see other fixes for Glow-Worm.