Request for advice on dealing with faulty motorised valve.

[bstock]

Hi, have been reading through the excellent information on this site for a while now as having bought my first house (yay!) I am now starting to exhibit symptoms of the DIY fever

My first post, but almost certainly not my last, so go easy on me!

I have a fully pumped indirect heating system, and it would seem the 3-port motorised valve has packed up. Having carefully worked through a series of tests and check I have reached the following conclusion:

The valve is a British Gas one (BGMVSP-23) and it would seem the motor has given up as I get 240V across the live(white)/neutral wires when the CH is on, and 240V across the live(red)/neutral wires when the HW is on, but the valve never switches, it is permanently set to deliver only HW (and thus our CH does not work, although I can force the valve manually).

So my questions are:

* Do people agree with the diagnosis, i.e. the motor is dead/jammed?

* What would be the simplest/cheapest route to sort this out, can I just get a new motor rather than a whole new valve? And if so, would something like this be a suitable replacement?

* Having looked at what is available to purchase, would it be worth taking the opportunity to simply replace the whole valve anyway with something a bit better (the current one seems fairly basic). The ACL Drayton, Danfoss Randall, and Honeywell valves seem like they might be of a higher build quality and might last longer, or is there very little difference?

Many thanks in advance for all advice offered!
Ben.

 

[HarrogateGas]

The valve you have is a Drayton valve............you can just replace the motor (about £10.00) or the whole head (about £30). The BG valves are very good valves, no issue with quality there.

 

[seco services]

if your getting no ch you want to check the white wire for voltage not the grey.

 

[bstock]

if your getting no ch you want to check the white wire for voltage not the grey.

Oops! I have been testing the white as you say, but managed to write grey instead.

 

[Hugh Jaleak]

If you plump for a new valve i'd say get the Honeywell for quality. Ive just bought one from heatingcontrolsonline to replace a Sunvic, as they seem to pack up for a past time....

 

[bengasman]

This is the time to upgrade your controls. Get a honeywell kit based on the 3-port valve, and a st 9400a; it will have several advantages.
Standard configuration
Proper wiring centre
New diverter valve
Completely independent use of ch and dwh; this will give a drastic improvement in response time and performance.

If you really got a diy urge, clean the system; 9 out of 10 suffer from corrosion/sludge to some degree, some a little, some a lot.

 

[bstock]

Cheers for the feedback so far.

I went and got myself a Honeywell programmer to replace the old mechanical one, along with a replacement synchron motor for the valve.

I am now a bit stuck though, as having installed the new motor it seems to have made no difference, the HW still does not operate the valve when turned on.

Has anyone got advice as to what the problem might be? The motor never seems to do anything, although it gets enough current that it is able to lock in position (manually moving it), and then resets when the HW is off.

Seems unlikely, but could the new motor be dead, or is there something else at fault here?

I have included a screenshot of the new motor installed just in case it helps.

Motorised valve

• bstock
• 17 Oct 2009
• 1

Many thanks in advance,
Ben.

 

[seco services]

hw has nothing to do with the valve.

if you fitted the motor then switched the electrics back on the valve will be in its relaxed position.
if you then switched hw on only you won't see nothing move as its already in hw only position.
it will only move when heating called for.

switch hw off heating on it should wind itself right across.

 

[bstock]

hw has nothing to do with the valve.

if you fitted the motor then switched the electrics back on the valve will be in its relaxed position.
if you then switched hw on only you won't see nothing move as its already in hw only position.
it will only move when heating called for.

Sorry, tired, stressed, really wanting central heating ... that is what I meant to say (again ) . I need to get better at proof reading my posts.

I am unable to get CH, and turning it on fails to operate the valve ... despite the fact I have replaced the motor and there seems to be current supplied to it.

Ben.

 

[seco services]

so you have switched heating on hw off ?
the motor should wind itself fully over.

if it fails i would say the pcb is faulty as you say its a new motor
you got power to the motor but its not winding across.

 

[bstock]

Hey,

correct - HW works fine (triggers pump, etc), but turning both HW and CH on or just CH on does not trigger any reaction from the valve at all.

Manully moving the valve lever to the far right triggers the pump for the CH, and the valve does not seem jammed as using the trick to manually lock the valve in the mid-position and then request HW to get the CH works.

The circuit for the valve seems so simple that I find it difficult to believe that something has gone wrong there - though I am of course a newbie here, so feel free to tell me otherwise.

Is there anything I can test to try and conclusively identify the issue, e.g. voltage across the motor, etc.

Many thanks,
Ben.

 

[seco services]

have you tried the motor out of the unit ?

 

[MANDATE]

could be contacts in microswitch No 1. Power has to pass through these contacts in this switch to drive motor . Also valve spindle may be too stiff for motor.

 

[bstock]

have you tried the motor out of the unit ?

I did - in that I tried operating the HW/CH controls with the motor only connected to the PCB but not actually driving the valve.

Doing that still got no response from the motor that I could see, although as mentioned the 'stalling' seems to work in that I can rotate the motor head while there is power to it (CH on) and upon stopping it locks in place (coming unstuck when the HW is turned off again). While doing this I can feel the motor faintly vibrating as well.

Cheers for your help so far, I was really hoping the new motor would solve our CH woes, and am still keeping my fingers crossed I don't need a new valve for both reasons of cost and expediancy. Does this look like a losing battle to you though?

Cheers!
Ben.

 

[seco services]

I did - in that I tried operating the HW/CH controls with the motor only connected to the PCB but not actually driving the valve.

i'm still with a faulty pcb.

Does this look like a losing battle to you though?

Cheers!
Ben.

i would say so