Drayton MA1 Valve not allowing heating and water at same tim

[Montys]

Hi,

I wonder if anyone can point me in the right direction here please?

We moved into a 7 year old house and noticed that when the central heating was on together with the water heating on at the same time, then only the central heating was working.

So, we were advised that the Drayton MA1 mid position actuator was stuck, so we had this changed, and it 'seemed' to work. At least when the electrician was here to test it. Once he went, it reverted back to working as before.

We had an electrician come in, as a central heating engineer checked the system and said the valve was working in both positions, therefore it must be electrics.


We get around this by heating the water when the central heating is not needed

Has anyone seen this situation, and if so, what's the answer please?

thanks

 

[seco services]

have you watched the indicator on the side of the valve to see what it's doing ?
what position is the marker when both are calling for heat ?

if the valves working as it should be then the electrics must be wired right.

 

[matt1e]

could be balancing issues, do you have one of these on the cylinder coil

or

 

[Montys]

Hi,

Thanks - yes, I think so, there is one that looks similar just above the Grundfos pump

 

[Montys]

Hi,

Thanks - I am just doing some testing

Currently, the situation is as follows

With Heating on, the slider at the side is at the far end

WIth Just water heating on - the slider is at the near end

WIth both water and heating on, the slider is in the middle

I checked the back too(far end) which has a thicker slider and this moves too as follows

Heating only on - on left hand side
Both on - in the middle
Water only on - on right hand side

 

[seco services]

so the valves working as it should.

 

[Montys]

Yes, this is true, but this what happened when we had a new valve put in, so at the moment, it is under testing and for 2 hours, still working correctly, but will let people know if and when it decides to stop

 

[Montys]

well,

Everything was working fine and then, it all stopped and reverted back to not working again.

So after about 2 -3 hours of working correctly, with both heating and water on, only the water was working, no heating (even though thermostat turned up)

The setting on the valve hadn't moved, so they were both in the middle as expected, but no heating working.

So it seems to work when first set, but then fails after 2 -3 hours.

 

[twgas]

In your first post you said;

when the central heating was on together with the water heating on at the same time, then only the central heating was working.

and then you said;

with both heating and water on, only the water was working, no heating (even though thermostat turned up)

They contradict one another - which of the two is correct?

 

[Montys]

Yes, sorry - quite correct, the latter is correct, when both on, only the water is working, the heating is off (even though thermostat is turned up and when water taken off, the heating comes on - this is how we noticed it initially, so for any confusion

 

[twgas]

If you isolate the eletric supply to the whole heating system, does the valve move to the hot water position?

 

[Montys]

It's difficult to know, without taking all the electrics out for the house, which I could do - what does that say if it does?

 

[twgas]

without taking all the electrics out for the house

That is not correct, either the statement or the installation.
If the valve doesn't move it's stuck, if it does it isn't.

 

[Montys]

ok - I have just put both heating and water on and the valve has moved to the water only position, so heating is off again - so the valve moves fine

 

[twgas]

After 2-3 hours the water should have shut off via the cylinder stat, unless the cyl stat is set higher than the boiler stat.
I'm suspecting the wiring is not correct, do you have the means to check the electrics (multimeter)?