2 port valve not opening

[SJM76]

I have an SVM 1802 that isn’t doing its job. When the thermostat is calling it doesn’t move.
If I bang it a couple of times it then comes to life. Is this the head or the value at fault?

It does manage to close ok once the heating has reached the set temperature.

 

[muggles]

Probably the head, but hard to be certain without doing more tests. You need to take the head off and see whether there is any stiffness in the valve itself, and also observe whether the head operates correctly with no load on it

 

[SJM76]

There is no stiffness in the valve. If I take the head off and set the thermostat to call nothing happens unless I bang the head a couple of times.
Is it worth taking it apart to see if anything can be done or is it best to find a new one? This model seems to be hard to find though, do you know of other brands that will fit on the valve?

 

[ianmcd]

I have an SVM 1802

Is it definitely SVM and not SZM

 

[SJM76]

Sorry yes it is SZM

 

[ianmcd]

Sorry yes it is SZM

O thanks, that valve is what is called MOMO means motor open motor off, most are motor open spring return so you can not use another actuator, they are readily available though just google sunvic SZM 1802