new 3 port valve actuator - odd results

stator

I've replaced my own three port valve actuator because a heating engineer let me down. I did a like for like replacement of just the actuator.

Now the hot water works fine, but the heating only comes on if the hot water is off. The HW and CH are both supposed to come on in the morning, and then the HW goes off at 9:10am and the CH stays on. So what's happening is that the CH is off when it should be on but comes on at 9:10am.

The 3 port valve without the actuator seems to turn ok.

Do you think I have a duff actuator and need to get another one?

The old one was broken and was stuck on hot water only. So I'm a little confused why the CH is working but only when the HW is off. It must be moving the valve, but won't stop in the middle?

It's a Drayton MA1

Alex1983

Have you got a multi meter? What voltage do you have on grey, white and orange when you have heating and hot water on?

stator

So the results are as follows:
Water only: Orange : 230v / White: 23v (not a typo) / Grey: 0v
CH Only: Orange 230v / White 230v / Grey: 230v
Both: Orange 230v / White 23v (not a typo) / Grey: 0v

I've double checked all the wiring is correct as per the Drayton installation manual.
Any thoughts?

Alex1983

The 23v is the issue.

You should have

HW Only - 230v orange only
CH Only - 230v on all 3
Both - 230v orange and white

The 23v on white is strange, the white cable on the valve will trace back to the room stat. Would probably be worth linking the room stat out to start with, if your confident to do that.

stator

The room thermostat is a wireless system, but it's Drayton so I was thinking of just replacing it with a wired Drayton unit which you can get for about £15 and it looks like they use the same backplate, so no wiring required.

dggar

stator wrote: »

The room thermostat is a wireless system, but it's Drayton so I was thinking of just replacing it with a wired Drayton unit which you can get for about £15 and it looks like they use the same backplate, so no wiring required.

I can't quite see how you replace a wireless thermostat with a wired thermostat and not have to wire it to the boiler.

Alex1983

I would guess he's thinking of swapping it with the wireless receiver, it will be the same back plate so won't need to alter anything.

I would link the reciever out first to prove your fault, just take the receiver of the back plate and join the cables in 1 and 3 together, leave the receiver of the back plate, be care as it will be live, and then test your 3 port to see if it cures it.

stator

dggar wrote: »

I can't quite see how you replace a wireless thermostat with a wired thermostat and not have to wire it to the boiler.

Just temporarily to prove where the fault is.
I know having a room thermostat in my airing cupboard isn't much use :rotfl:

stator

Alex1983 wrote: »

I would guess he's thinking of swapping it with the wireless receiver, it will be the same back plate so won't need to alter anything.

I would link the reciever out first to prove your fault, just take the receiver of the back plate and join the cables in 1 and 3 together, leave the receiver of the back plate, be care as it will be live, and then test your 3 port to see if it cures it.

I tried as you suggested but it behaved exactly the same. Water or Heating, the actuator moved the valve to one or the other, never stopping in between

Alex1983

It's strange.

Can you try putting both on and testing what voltage you have on connection 1 at the receiver back plate. It should be 230v. If its 23v I guess it could only be the programmer. If it's 230v then the next thing you could try is to put the receiver back and split the cables at the white of the diverter valve and make sure you have 230v coming from the receiver.

stator

Thanks I'll give that a try.
I was thinking I might just buy the Drayton set. Then I can replace the Programmer and the 3 port valve motor and even the two thermostats and it would probably still work out cheaper than calling someone in. It would all be like for like replacements so should be simple
http://www.screwfix.com/p/drayton-pbbe58-biflo-central-heating-control-pack/1344g