3 point actuator issue (Drayton MA1) - confusing fault

258 Posts


Hi there.
My central heating system (separate water tank) has developed a fault and I cannot quite worked out was has happened.
A few days ago, I noted that the thermostat was telling the central heating to come on but nothing was happening.
The acutator was in the default hot water position (W) - if it were working, the acutator would have either been in the middle (M) or central heating position (H).
I did some testing, however, and if I used the lever to manually move the acutator to the M position, the heating works fine. Furthermore, if I turn off the hot water but keep the heating on, the acutator moves to H position automatically.
Just to confirm - when the acutator is in all three positions, the boiler fires up as expected (assuming the central heating and water tank thermostats are calling for it).
The fault seems to be with getting the actuator moving from the first position automatically.
Although the motor seems to be working (as the actuator moves from M to W on its own), I tried swapping the motor for a replacement but have the same issue.
Any advice on what to do would be much appreciated - do I need a whole new actuator head?
My central heating system (separate water tank) has developed a fault and I cannot quite worked out was has happened.
A few days ago, I noted that the thermostat was telling the central heating to come on but nothing was happening.
The acutator was in the default hot water position (W) - if it were working, the acutator would have either been in the middle (M) or central heating position (H).
I did some testing, however, and if I used the lever to manually move the acutator to the M position, the heating works fine. Furthermore, if I turn off the hot water but keep the heating on, the acutator moves to H position automatically.
Just to confirm - when the acutator is in all three positions, the boiler fires up as expected (assuming the central heating and water tank thermostats are calling for it).
The fault seems to be with getting the actuator moving from the first position automatically.
Although the motor seems to be working (as the actuator moves from M to W on its own), I tried swapping the motor for a replacement but have the same issue.
Any advice on what to do would be much appreciated - do I need a whole new actuator head?
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I just assumed that the motor was broken but as the acuator can move from M to H on its own, it seems that the motor is working.
I am wondering whether there is perhaps a PCB fault (on the actuator) that is preventing the heating thermostat from telling the actuator to move the motor from default W position.
.withdrawal, NOT withdrawel ..bear with me, NOT bare with me
.definitely, NOT definately ......separate, NOT seperate
should have, NOT should of .....guaranteed, NOT guarenteed
Thats assuming the system is wired up correctly with the programmer and cylinder thermostat giving correct voltage demand to move the valve body.
As Grumbler has mentioned, checking the voltages on all of the motorised valve wires is super important. Every system is Bespoke Some systems are wired up to give central heating and hot water simultaneous ~when hot water demand ceases so will central heating but central heating will commence when the cylinder stat again calls for heat.
Sometimes that is the way it has been designed of left following other component exchanges
Maybe purchase the brass valve body, attach it to your actuator and switch your programmer,cylinder stat, room thermostat in different combinations of demand and watch the valve motor/close in different demands.
Since the introduction of wireless/internet heatig/water controls its even more bespoke. More room for error
The spindle on the valve should be smooth and easy to move through a ~30-ish arc? It should thunk solidly at each end of travel as the ball valve makes contact.