Honeywell F2- 9421 Diverter Valve

9 Nov 2011
Reaction score
United Kingdom
I hope someone can give me an idea about fixing this valve.
My CH stopped working yesterday but HW worked as normal. Boiler seems fine (only 3 years old). Heard it might be a faulty diverter valve so, with boiler power off, I moved the little levers from auto to manual. There was resistance and they whirred back to auto. Its an S plan system so I put the CH valve lever to manual and latched it. Switched on, and radiators heated up (although not as hot as usual).
The valve is a Honeywell F2 - 9421 and I believe its possible to just replace faulty parts rather than the whole thing.
Can anyone indicate what part could be faulty and how to replace it?
Thanks for any help!
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Just looked at the less obvious side of the valve - it's a V4043H. The F2 - 9421 is maybe not its model number. Sorry!
Probably find the motor inside has failed. Don't waste your time buying a cheap copy motor...they often last only 12 months.
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