diverter valve alpha CB50

2 Nov 2011
Reaction score
United Kingdom
Changed the diverter valve of the alpha CB50 [just the motor and washer] as the diverter valve was leaking think it was the spindle of the diverter valve motor as the black box in which it rests was leaking.

I drained the system before I did the above.

The leak has stop but now I have new problems.

The radiators heat up very very hot even when the thermostat is set to zero.
The pump is making a constant crackling noise.
Even if I set the dial to just DHW [Domestic hot water] the CH[central heating] still comes on.

what could be the problem which explains all the above
1] faulty heat sensors but than when just the DHW is switch on the CH should not come on as well [The dial has off, DHW, CH and reset]
2] Diverter valve not working properly.............i get both hot water and CH. Though the CH switches itself on even when just the DHW is on. is the DHW being pumped into the CH would this show as a significant pressure increase.
would be most grateful for any suggestions / solutions.
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