Glow Worm 45 60 Water Too Hot

[4077mash]

My old old glow worm is still running well but the water is almost boiling. Is it likely to be as obvious as the thermostat? Or the thermocouple?

Gravity water, pumped heating, both far too hot with thermostat in min position though the boiler does cycle on and off periodically.

Changing it means a rebuild of half the house so I'd prefer to get it fixed if poss.

Cheers!

 

[45yearsagasman]

Get a new thermostat fitted. Cheap fix if it works. It is possible to control HW temp with a simple 28mm tapstat or converting to C plan, or better still to a proper fully pumped system. Ask your local friendly heating eng for a quote.
Better still is a new boiler as those old lumps are way past their use by date.