moroised valve

[old-wos-is-name]

Hi All,

The motorised valve on my central heating system is opening and closing all the time, from open to close in a few seconds and back again, making a clicking noise. I have removed the electrical part and set the valve by hand. any idea what the problem may be?
thanks,

[GRUMPY]

The elictrical motor that that turns the valve has gone faulty,you can buy these at most places that sell central heating parts,these are not expensive
you can of course replace the whole unit but this is quite expensive.
Hope this helps.

[buildersmate]

These motors contain a profiled cam and microswitches that sense the position of the shaft connected to the water valve. Depending on whether it is a 2 or 3 way valve depends on the number of microswitches. These switches then connect into the logic wiring of the wider CH system to sense whether the valve is in the correct position for the requirements of the system (either OFF, calling for HEAT, calling for HEAT/WATER, or calling for BOTH).
What is happening is that the microswitch or the cam arrangement has gone u/s and the motor cannot work out when to stop rotating.
Since the motor and control cams/microswitches are all part of the same sub-assembly, Grumpy is correct that you will probably have to replace the motor assembly - a relatively straight-forward task that does not involve having to tinker with the plumbing side.

[old-wos-is-name]

thanks Gents, I will get a motor unit from ebay.

[AlBags]

The bit you want is just called a head.
5-wire (unless it's a 28mm 2-port)