Drayton MA1 Valve - How to Test

28 Apr 2006
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United Kingdom
I have replaced the valve housing of Drayton Mid Position Valve (MA1) it was badly corroded and jammed.
Having replaced the actuator I still seem to be getting Central Heating when only Hot water is turned on.
How can I test the actuator?
I lock the lever down and click it in place but the lever does not unlock when I switch on heating.
Is it possible it is just the motor which is duff as I believe these can be replaced?
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Just got nosey and took the top off the actuator, the motor was very warm, unscrewed it and switched back on and the actuator motor turned.

Noticed there was a small black piece of plastic loose inside the valve, I cant see where it is meant to be attached, but, it looks like it is a lever of some kind and may be supposed to poke out of the casing opposite the release lever is this the "valve position indicator"?
Would the fact that this has broken off stop the actuator working?
Fella your way off the mark with your diagnostics get a decent plumber/ rgi
To have a look at it for you
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