Hot water Motorised Valve / Motor failed several times

Grippo

Hi, I am just wondering if anyone has any ideas of what might be causing the motorised valve to stop working several times at my home?
The same thing has happened 4 or 5 times now with the motor being replaced around 3 times and he whole valve being replaced twice by a private engineer and more recently a British Gas engineer, via a Homecare contract.
The valve was most recently replaced 6 weeks ago, and the motor 11 days ago. But today it’s stopped working again. So no hot water from the taps or shower. But the central heating is working fine.
I asked the last engineer if something else was causing the valve or motor failure. But he said no. Some last for 30 years and it’s just down to luck. But surely this can’t be the case.

I have an engineer coming out today again, but any suggestions would be great. As I have no confidence of this ever being fixed for any length of time.

Section62

Grippo said:

Hi, I am just wondering if anyone has any ideas of what might be causing the motorised valve to stop working several times at my home?
The same thing has happened 4 or 5 times now with the motor being replaced around 3 times and he whole valve being replaced twice by a private engineer and more recently a British Gas engineer, via a Homecare contract.
The valve was most recently replaced 6 weeks ago, and the motor 11 days ago. But today it’s stopped working again. So no hot water from the taps or shower. But the central heating is working fine.
I asked the last engineer if something else was causing the valve or motor failure. But he said no. Some last for 30 years and it’s just down to luck. But surely this can’t be the case.

I have an engineer coming out today again, but any suggestions would be great. As I have no confidence of this ever being fixed for any length of time.

He's talking nonsense.  There is some degree of luck in how long a component like a motorised valve will last, but you've had a repeated pattern of 'failures' which would - if his theory was correct - make you one of the most unlucky people around.

Has anyone checked the wiring to ensure it is the valve - not the installation's wiring - which is at fault?  E.g. a bad connection could stop the valve working properly, giving the impression to a lazy plumber that the valve had failed.  Alternatively, problems with the quality of the electical supply (e.g. low voltage) could cause premature failure of the valve motor.

You may need an electrician to give the system a once-over, but you probably won't get that with homecare.  Much easier for them to swap out the motor and/or valve and tell you you're just unlucky.

Grippo

The engineer has been this morning and has questioned the wiring. So he is coming back later today with someone else to check that side of things. Hoping for a positive outcome.
Thanks for the reply.

grumbler

Grippo said:

So no hot water from the taps or shower. 

Can it be the HW thermostat, not the valve?
Unfortunately, many modern 'engineers' can't do proper fault finding (e.g., in this case, checking voltage on the valve terminals in different modes) and instead just keep changing various parts and modules.

ThisIsWeird

Hi Grippo.
For how long have you lived in this house? And when did the first failure occur?

Grippo

ThisIsWeird said:

Hi Grippo.
For how long have you lived in this house? And when did the first failure occur?

We’ve been in the house three years, and the first time this happened was around December last year.

ThisIsWeird

I agree with S62 - the chances are there's a common cause. And that is most likely to be an electrical issue.

What, tho', I haven't a scooby...

These 3-port valves are weird in that they are 'held' in the central - catering for both CH and DHW - positions using a half-whatsit, served by a diode and a resistor. Ie, the motor is fed a half-voltage or summat, so it's always half-powered, enough to hold it there against the return spring.

I recall replacing a 3-porter for a friend a few years back, and the damned thing failed again in short order. They called a sparky out, and they reported finding a 'wiring fault' in, I think, the programmer, but that's all I know. Their situation was different, tho', in that they'd just moved in, so the house presumably came with this fault. In your situation, it clearly worked fine for a couple of years, so it cannot be down to a wiring 'mistake', but could still be a wiring 'fault'.

But I cannot figure out what it could actually be. I hope that helps...

ThisIsWeird

Hi Grippo.

What type of programmer/timer do you have? I'm trying to recall if it was an internal fault to that device - a typical LP722-type jobbie - that was responsible. Perhaps burnt relay contacts that caused an unacceptable switching arrangement, but I'm stabbing in the dark here.

Q - did the valve 'buzz' at all when it shouldn't? Ie, it will 'whirrrr' for around 3 seconds when it's operating, but should then stop and remain silent. I think my friends did a 'buzzzz'... when stopped in some postitions.

Anyhoo, has the engineer been out yet?

FFHillbilly

Grippo said:

Hi, I am just wondering if anyone has any ideas of what might be causing the motorised valve to stop working several times at my home?

please define "stop working". what are the symptoms?
I'd recommend an electrician to diagnose the fault, you need to know exactly what is happening.
what sort of heating controls do you have for the DHW and CH? 

I'd recommend employing both an electrician and a plumber to sort this, often what happens is electricians will ignore any plumbing problems and plumbers will not even look at anything electrical and do things like replacing the valve only as they can't touch the motor