Sluggish CH motorised valve

[David J]

A few times recently I've woken up to find no domestic hot water, although the programmer is showing that the DHW should be heating. I have discovered that the problem is with a sluggish 3-port motorised valve. This is a Myson Power Extra 322, and it is about 13 years old.

If I gently tap this actuator, I can hear it move into the correct position. The LED then lights up, and all is well.

I've seen the actuator alone can be bought for about £45 - £55 online. The DIYs (B&Q, Wickes etc) appear not to stock such items.

My question is: can this actuator be lubricated or summat, to fix my problem. Does the spring return weaken?

Clearly it isn't broken, but should it be replaced?

David

[Another John]

David -- see the thread that I started earlier this evening: John Rumm and Roger Mills in particular have offered exactly the advice you need!

John

oops sorry: the thread is "Boiler problem: Heating OFF, water ON"

[David J]

Many thanks - a coincidence that we both posted the same problem today. Mine has been lurking for weeks. In fact I thought that it had gone away!

I'll pull the cover off tomorrow to examine the innards, and check the movement of the valve. There is a manual lever on the lower side of the Myson unit that I assumed did the same job as the actuator, but reading the Installation instruction online, I now think that it does something else.

I'm hoping that it is just the actuator at fault so that I do not have real plumbing to do! I can manage these electrics myself...

David