Help - Mid Posn Actuator Problem.

[Maggs]

Hi,
I have recently moved house and I have inherited a problem with my central heating controls.

I have the following devices installed

Worcester Greenstar Ri Boiler
Drayton MA1 Mid Posn Actuator
Drayton Lifestyle LP552 Controller
Drayton HTS3 Hot Water Tank Thermostat (set to 55 Degrees)
Salus RT300RF Wireless Room Thermostat (Set to 22 Degrees)

My problem is this:

All the individual components seem to work and function OK individually. The Mid Posn Actuator moves to all 3 posns, the tank thermostat and room thermostat both switch on and off and the controller switches on and off correctly.

Unfortunatly the system as a whole has a problem.

When the controller switches both Heating and Hot Water on at 5:00am, both room thermostat and tank thermostat are calling for heat.

The boiler fires up and the Mid Posn Actuator moves to HW to heat the water as a priority.

Once the water is at temperature the thermostat switches off, HOWEVER instead of the Actuator moving to the H(eating) posn it stays at the HW posn and the system shuts down.

The only way i can get the heating to come on is to

1. Advance the controller to make both H and HW OFF
2. Unclip the Tank Thermostat and blow on it to cool it down to make it "click" and think it needs heat.(it dosen't as the water is almost boiling by now!!)
3. Advance the HW to ON (the boiler will fire up and Actuator move to HW)
4. Advance the H to On
5. Advance the HW to OFF ( the boiler will continue to run and the Actuator will move back to H)

Some times i can get the Mid Posn Actuator to move to the Mid position but i havent worked out the sequence of On/Off presses to get to do it yet.

Since all the items work individually do you think it is a wiring issue?? or is the Actuator dodgy??

Thanks

 

[Andy™]

if you have basic knowledge, it shouldnt take too long to go over it with a wiring diagram and make sure its wired correctly. then use a multimeter to make sure you have the correct voltage at the correct points

of course, that all assumes you have some idea and a screwdriver. and not being colourblind is also a help

 

[ProDave]

Disconnect (physically undo) the actuator head from the valve body of the 3 port valve.

Then try all combinations and see if you can see the actuator head moving to the different positions.  Often it's the valve itself that's stuck and jammed up and not allowing it to move.

 

[Paulp]

I have had two honeywell programmers with an odd fault they will not switch both hot water and heating on together for some reason(apart from being faulty)

If you put hw on fist it would not switch ch. and visa versa. The display did indicate it was switching but the relay did not click of produce an output.

Do you have any reason to suspect it was wired up wrong from the start?