Drayton 3 Port motorised Valve MA1 Actuator only.

Product Information

The system is a conventional gravity-fed system with gas condensing boiler, Lifestyle LP522 programmer, Drayton RTS1 room-stat, Honeywell tank-stat, Drayton MA1 MPV and ACL Lifestyle Wiring Centre.

Anyway having diagnosed this far I'm going to leave it with the central heating and the water heating on full time to see if I can get the temperature in the bungalow up to the expected level. I assume if the 3 way valve was working properly and the heating side wiring wasn't requesting heating then the 3 way valve would be set to Heat and the central heating wouldn't work. However although I heard the main valve move and watched the plastic lever move, I haven't heard anything from the 3 way valve and the plastic lever seems to be floating.I have looked up the model and found it to be a "drayton mid position actuator MA1" and wanted to know what i need to do to replace it . So, am I trying to fix a problem that isn't there, (other than not having any hot water yesterday morning)? Perhaps I've never noticed the actuator staying in the H (or the last selected) position before. 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:

So, it seems as though everything is working normally until there is a demand for Heating only, when, once it is satisfied, the actuator remains in H. This is repeatable! The best advice I got was that my system was working as it should and I am glad to say it is. From those who knew, I learned what it is that holds the MPV in the H position even when there is no demand for heating, the HW-OFF feed from the programmer. As I said, when I turn the water on, the actuator does move to either the mid or W position depending on whether there is demand for Heating as well. In that respect it all works perfectly. With power applied to the white wire only, it will move to the mid position for hot water and heating. Now some heat is getting to the cold radiators. The new (compared to the others) double radiator is doing something I haven't encountered before. The rear part is heating up but the front part is staying cold. It doesn't have air in because I have bled it (amazingly after a long search I found a bleed screw) and it was full of water.I have a really weird problem with a Drayton MA1 mid-position valve and I can't find any reference to this specific problem. 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.