Glow worm fuel saver f not working?

I have a Glow-worm Fuel Saver F boiler which has started to make a loud whistling noise when it's been turned on for a while and the whistling seems to increase in volume the higher the thermostat is set. Any thoughts on what might be causing this and how it can be rectified please ?

Neil Mc
February 2018

I had this problem, it was caused by the air pressure switch not working. This can be because the fan is not working, but sometimes they just stick. If you bang the left hand side of the outer casing near the bottom while the system is calling for hot water it might clear the problem, temporarily at least. The switches are pretty expensive to have replaced, so it is worth a try. (No qualification needed for this approach!!)

Fuelsaverman
May 2008

You need to go to college for a few days an get registered,
until then you are at the mercy of the wolves.

botdog
January 2008

yes call a CORGI registered engineer. Legally you are NOT QUALIFIED to work on/repair gas appliances. And if you are you should be prosecuted. So should others like you.

Mr Gas
July 2007