What should I replace my mid position actuator valve with?

[JoeyT]

Have had an issue where the heating comes on when it should, but gets stuck on when the timer and thermostat turns off.

Boosting the hot water and then turning it off again always fixes the issue.

Found out today that the actuator sends a signal to the boiler and pump to turn on, and this is what wasn't turning off. The valve is free moving (can move it with my fingers), the actuator is also able to turn it, but sometimes sticks on heating

I need to replace the Drayton, head that the Draytons aren't that good, what should I replace it with?

 

[ianmcd]

you can normally only change actuators with like for like, if you want a different brand you will need to change the whole valve

 

[JoeyT]

Thanks. I decided to just replace the entire valve and actuator so I've ordered both.

 

[ianmcd]

Thanks. I decided to just replace the entire valve and actuator so I've ordered both.

Why would you order both ? the valve comes with the actuator ?

 

[Hugh Jaleak]

Not sure what you've ordered, but if you're replacing the lot, go for Honeywell.

 

[JoeyT]

I ordered this: https://www.amazon.co.uk/dp/B00COD9KKC
Should I order this instead? https://www.amazon.co.uk/Honeywell-V4073A1039-Mid-Position-Valve/dp/B005IM1EG4

Ordered both the actuator and valve because it is a bit stiff turning sometimes. I can do it with my fingers some of the time, but today I had to turn it with the adjustable spanner. Probably could do with a good purge.

 

[Justin Passing]

If it's only a stiff valve, you can if you're handy (think Steve off the Repair Shop) try dismantling and greasing. If it's the switches, ditto. If it's the mechanical bits in the head, I've never tried on a Drayton.
Honeywells are easier for that caper.
Very understandable if you CBA!

If you get a drayton head & valve, and it's only one bit, you'll at least have a spare for the other.

 

[JoeyT]

Thanks. I'm capable of doing both, just I'm sure these are the original from 20 years ago (which may or may not be old for these parts).

I'd just rather make sure it's done as I've been fighting with this for months. (Waking up at 3am and the heating is stuck on full / hot water heated up above the thermostat temp and is scolding hot - which is why I slightly suspect the actuator as it shouldn't send the signal to the boiler when it is in the mid position but it has a few times).

 

[Justin Passing]

There's about 2 dozen ways they can be wrong, including variations on :

never wired up right in the first place but we only just noticed because....
or
that bit of leakage current didn't used to matter but now the boiler's seeing it and turning on...
or
the programmers messing about...
or
owner thought the spindle should turn more so broke it with a spanner
or
it's in backwards and the wiring has been changed to make it work some of the time

etc.
None of which are the thing's fault. Good luck!

 

[JoeyT]

Wired fine, issue was there when we bought the house, but only happened once in a while, now every day. I changed the programmer and thermostat but the same issue continued (didn't change because of this issue, just wanted NEST).

When it was stuck, I confirmed the relay in the timer (NEST hub) was switching correctly.

Realised a few days ago that by manually moving the lever to heating mode on the actuator will trigger the boiler and pump (despite timer and thermostat not calling for heat /hw, so looked up the wiring diagram to see how it is all connected and confirmed it does this by design (signal to boiler / pump when call for heat comes from the actuator). Then realised that every time the heating was stuck, the actuator was stuck in the heating position when it should move back to HW position when it's not energised.

This is why I came to the conclusion that it is either valve or actuator. I got it working for a week when I loosened up the valve, but even when it was loose, the actuator would get stuck, although the valve is stiff again, may as well replace both.

Thanks for replying, I will do the swap over the weekend, will report back. Hopefully I don't flood the house

 

[Justin Passing]

NB that's not a "heating position", the lever's there to open the valve for filling/bleeding. It doen't necessarily turn the boiler on. Some do, some don't, some do sometimes.

 

[JoeyT]

I'm not sure what you mean, I have a "W M H" indicator, it either opens the valve to flow through to the cylinder, both or the heating loop. Mine does turn the boiler and pump on, I can manually move the lever and turn on the boiler and pump when there isn't a call for HW or heating.

Manually boosting the hot water for a second and then turning it off is enough to move the actuator to M or W, stopping the signal to the boiler / pump.

At least, from what I can tell from YouTube videos and wiring diagrams (and fiddling with it).

 

[Justin Passing]

Fair enough. It's the Mid position which may or may not turn the boiler on, if you put it there with the lever.

 

[Dereekoo]

When its stuck and not moving to where it should be give the unit a tap or two with something, sometimes it just the microswitches within the unit not making a firm enough contact to initiate whats required.

 

[JoeyT]

I did just swap over the actuator on my lunch break. The new one also gets stuck in the H position, I realised it's moving all the way over to H and then the manual lever locks in this position until there's a call for hot water at which point it unlocks and goes to W or H.

I took the old one apart to see how it works, and the mechanical behaviour of the new and old are the same. Could be the contacts as you've said.

I'll leave it a couple of days to see if it fixes the issue (without replacing the valve just yet).