I have a Glow Worm Fuelsaver Mk2 model 40B boiler that is probably the best part of 20 years old. It has a delay in firing up. When I switch it on or when the timer clicks in, I can hear the pump open upstairs and hear the usual clicking and sounds in the boiler but then it takes four minutes until it fires up. Once the flame has fired it works perfectly normal. A month ago I assisted a friend to install two new radiators at my house and this was done on two consecutive weekends which meant draining and refilling the system twice. The problem has only happened since then. I am having difficulty locating a manual for this boiler as it is discontinued and I can't find any Gas Council Number in the unit although it has been suggested that it could be a 41 313 78 which relates to a Fuelsaver 40R. Could anyone advise on what this problem could be. It is not a major issue as everything is fine once fired up but I was wondering if it may leak any gas within the four minute delay and if this delay may get longer. Any help would be of great value to me.

eljay, November 2009

also with the new government scrapage scheme now in place for all G-rated boilers you can get £400 off the cost of a new A-rated appliance and depending on the make extra warranty if installed by recommended installers. If you don't have any luck with the old unit go for this offer..

Iain, January 2010

if you remove the outer cover (1 screw underneath and gently lift off) you'll find the tech badge fixed on the outside of the outer burn chamber casing. the G.C. No. should read 4131596 for a glow-worm fuel saver 40B Mk II.

This boiler is range rated, meaning the burner pressure can be adjusted between a set range as laid out by the manufacturer depending on the size of installation (amount of radiators it heats) the range rating is also found on the tech badge. by adding 2 extra rads you may have put the unit under strain and would need to re-calculate your whole house with the additional add-on's to find what input you need in Kw's. it is very important not to over compensate your burner pressure as this leads to a spiral of problems which eventually will lead to the unit failing completely as well as being extremely dangerous.

As for the delay in the unit kicking in when calling for heat you will probably find the thermostat is carbonised and if not in any way damaged simply needs a clean. My advise is to call a registered gas engineer to fully service the unit, if they open up the burn chamber remember all seals will need replacing to ensure it stays properly room sealed. if these are damaged you run the risk of the products of combustion leaking into your house, this can result in carbon monoxide poisoning for you and your family if the unit is not running well.

good - luck

Iain, January 2010