Drayton MA1 3 Port Valve Actuator Head 230V, 27651

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When there is a CH demand but no HW demand (tank stat satisfied or HW off at programmer) the valve moves to the CH position. A microswitch in the valve actuator switches a live supply to the orange wire - which then powers the boiler and pump. At the moment, there is nothing wrong with the system, thank goodness. It was a case of putting two and two together and coming up with five. The water was very cool when I showered and so I advanced the timer to heat it up. The boiler was working fine as I had the heating on at the same time.

That was why I came here and my misunderstanding has now been corrected thanks to John and flameport! That is, there is a shared (flow) valve which has to open to allow any water to flow, then a second 3 way valve which decides which way the water will flow. I was ready to go buy a new actuator as I believed this was the problem, however it appears to operate as described in the above discussion. If the boiler doesn't run when there is *only* a CH demand, it indicates either that the valve hasn't moved all the way to the CH position or that the microswitch isn't working.The MPV actuator is a BGMVSP-23. The control and thermostat is a Hive system. Boiler is a Worcester Greenstar Ri. System is gravity fed open vented system, tanks in the loft and HW cylinder in airing cupboard. With power applied to the white wire only, it will move to the mid position for hot water and heating. Boosted HW MPV stays in W. Boosted CH and MPV moves to H. Turn the boosts off and MPV remains in H and after a short time pump stops. From what you say, does the actuator stay in the H position when the demand is satisfied when the timer is still on (as well as when the timer shuts off) and if so, what is keeping it 'actuated' there and thus stopping the spring pressure from returning it to the W position? However, turning off the system power causes the actuator to return immediately to the W, relaxed, position under spring pressure. Turn on the system power and everything works as it should, until the Heating-only demand is satisfied when the actuator remains in H.

One side of the house, the radiators do get hot, Some of the other radiators don't, or at least take a long time (I've only recently put the hot water on constant). Pump is on flat out setting. This suggests that the radiators may not be balanced.I have a really weird problem with a Drayton MA1 mid-position valve and I can't find any reference to this specific problem.