Hi,
One year ago (almost to the day) the Drayton MA1 mid-position actuator was replaced (4 years old) on my central heating system as it wasn't operating correctly. It was replaced with another MA1 and the problem was solved. However, I have just switched on my central heating for the first time this year and find that I always get CH with HW even when the CH timer is off. I looked at the MA1 and can see that the valve position is in the middle (HW+CH). If I unsnap the actuator from the valve I can turn the valve manually. I then tried the following with the MA1 removed:
CH OFF
HW OFF
Moved manual lever to HW position
Switch on HW and MA1 lever remains in HW position - correct
Switch on CH and MA1 lever moves to mid position - correct
Switch off CH and MA1 lever stays in mid position - wrong
If I then nudge the manual lever, the MA1 lever then moves to the far-end (HW) which is where it should have gone without me nudging it. The lever seems to be getting stuck.
This looks like a problem with the MA1 but its only a year old - are MA1 prone to failure or is there something else that could be contributing to premature failure ?