Britony Combi boiler problems

[PSP-Paul]

I have had no end of problems with my britony combi boiler, and recently it has sprung another one on me.

When it is fired up and heating there is what can only be described as a kettle type whistling coming from the boiler. It gets quite loud and high-pitched. It lasts a couple of minutes, and then the boiler makes a small click noise as though some process has stopped. The boiler is then quiet for a few minutes, until making the same noise again.

I have always had problems with the boiler locking out also. It usually only allows me to run it for 15minute intervals.

Any ideas what the whistling noise may be? I have no background of this, so could be way off here...but it's almost like there is air in the boiler. Would this cause the problem? I recently drained the full system as i fit a few new radiators. There is a small twist valve bleed nipple type thing at the back corner which i think is to remove air inside, but when i twist it there is no hissing air noise!

Any advice would be fantastic!!

 

[Gasguru]

Assuming its a Brittony Combi 80 or 100 then:

Have you checked both the flow and return isolating valves under the boiler are fully open (22mm pipes left and right underneath). Make sure you don't have TRV's fitted to all radiators.

The lockout could be occuring due to a faulty overheat thermostat - had a few on this model go out of spec. Easy part to swap.

The clicking is the gas valve switching between solenoids (full or 1/3 power). The kettling is due to scale in the primary heat exchanger.

If your heating system is no more than 10Kw then set the plug C on the board to the 1/3 setting - it should cure the noise. See the Chaff website for the manual.