Motorised Valve not working

[OliverHill]

Hi

I'm new to this house owner type stuff but am keen to learn.

I recently moved into my first home and whilst the hotwater is working nicely my central heating will just not come on.

When I turn it on simply nothing happens at all. I have tracked the problem down to the motorised valve for the central heating system not working correctly.

If I move the valve to 'man on' position the rads do heat up when I have the HW on, but unfortunatly the HW soon gets to temperature and it all turns off again.

If I depress the dip switch on the CH valve the system does come on..but I decided not to force this switch down for long as I would imagine leaving it on with both valves closed would do the system no good at all!!

After playing around with the HW valve I see that when the tank temperature drops below that set the HW valve creeps open automatically and depresses the dipswitch causing the sytem to fire up. So I'm thinking there could be four possible problems with the CH and I'm at aloss as to diagnose which is causing the fault.

i) The valve motor itself
ii) The room thermostat (althoguh it is definetly making a 'clicking' sound when I change the required heat past that the room is actually at)
iii) The controller (although the led is on to signify the heating should be on)
iV) Loose wires at some point (although a quick visual check revealed nothing)

I'm not sure how much use model numbers would be, although it appears to be a honeywell system. The HW valve is newer than the CH valve. I do have a multimeter and am not scared to use it, so some information on where there should or shouldn't be some voltage difference would be useful

For the time being I was thinking of taping the CH dip switch down and leaving the valve on manual open. Obviously I would then have to control the heating manually on the controller and the CH would always come on with the HW. Any dangers in doing this?

Many thanks for any help

 

[OliverHill]

Just found out holding the switch in on the CH valve turns the CH on regardless of anything else including the programmer!?!

Guess this will be a very manual system.

In fact the only thing which seems to turn the boiler off now is turning down the stat on the boiler. What is this for anyway, other than to prevent it from overheating?

 

[sime10]

I don't know what the dipswitch is but no danger as the boiler thermostat should conrtol any danger items

 

[trooper]

the zone valve isnt functioning the way it should, if u unscrew the side screw and lift off the metal cover u will se a roundish synchron motor , this is replacable, and quite easy to do, these motors are prone to burning out. £15 to buy, 5 mins to fit.
or ill sort it for £150

 

[OliverHill]

Hi, thanks for the advise.

Probabbly got my terminology wrong. I said dip switches but they are more like micro-switches. Actually they remind me of those on my competition pro joystick back on the good old Amiga 500...anyway I digress.

I also said 'depress' for some reason when I actually meant press down or hold in. The switch is on the inside and I had to take the metal cover off to get to it.

I'll see about getting one of these motors then from a local merchant. I went to wicks, they didn't seem to have anything at all. Guess I'll have to ask around at work for a good local plumbing merchant in Aylesbury.

 

[MANDATE]

I would say you need to have HW off (for quietness) , turn room stat down, then put CH on and turn room stat up and listen or feel to establish if valve is moving.
I'm convinced it can't be. When you move valve manually you trigger the microswitch and boiler flashes up. Your moving the valve instead of the motor moving it
The valve spindle may be stiffish or the motor may need replacing.
Yes thats what the boiler stat is for, prevent overheating.
The CH should go off when the room stat is satisfied as it cuts off the power to the valve and the motor returns to its closed positon by the return spring

 

[MANDATE]

Wickes do have synchron motors, saw one on Monday

 

[OliverHill]

Right, Got myself a new motor fitted it..and nothing. Thought it was time to resort to the multimeter and put some kind of diagram together.

Unfortunatley it appears the system was wired in by a colour blind incompitent fool.

First Take a look at the HW side and everything looks logical. Then take a look at the CH side and WTF is going on here!!!

First a short key:
/ = a switch of some kind
+ = a connection (otherwise assume there is no connection when wires cross on the diagram)

Note that I have excluded the second stage of electrics which connect the microswitches on the valves to the pump and motor as these seem fine

Looks to me that the Green (Earth!!) wire from the controller should be attached to earth bundle and in fact it should be the second black wire (*1) from the controller that attaches to the Brown on the CH Stat.

I think this is where the problem is though. Unlike the Black wire on the HW side which is either live or dead when the HW is set to on or off respectively, the second black wire appears to be always live regardless of the CH setting on the controller (or the HW setting for that matter). Does this look like a faulty controller to everybody else too?

[code:1]
C BLUE ----------------------------------------------
H |
BROWN----- |
S | | |
T / | |
A | | |
T GREEN-- | |
| | |
| | |
| | |
C BROWN-- | |
H | |
| |
V BLUE ---------------------------------------------+
A | |
L | |
V | |
E GREEN ----------------------------------- |
| | |
| | |
| | |
C GREEN -- | |
O | |
N BLUE -------------------------------------------+
T | |
R --BROWN-------------------------------------------------LIVE
O | | | |
L / BLACK (Not Connected) *1 | |
E | | |
R --BLACK -- | |
| | N
| E E
| A U
| R T
H BROWN ---- T R
W | H A
/ | L
S | | |
T BLUE ------------------ | |
A | | |
T GREEN (Not Connected) | | |
| | |
| | |
| | |
| | |
H BROWN ----------------- | |
W | |
| |
V BLUE ----------------------------------------------
A |
L |
V GREEN -----------------------------------
E[/code:1]

 

[ChrisR]

You might want to look : here

In principle, it should be wired like :
this

 

[cross thread]

you should have 240 on the brown at the zone valve when heating is calling,if not have u a supply from clock ? then through the r/stat. if u have 240 on the brown at zone valve and assuming you neutral is correct it should motor.putting the permenant live fron the grey on to the orange this will fire boiler/pump on most systems

 

[OliverHill]

You might want to look : here

In principle, it should be wired like :
this

Thanks for the links very handy.

If we ignore the wire colours that have been used then I still think there is a problem with the controler. The honeywell diagram only shows 4 wires entering the controller/timer. If we first ignore the neutral wire which is there only for it's internal power loop, I have one HW switch wire and one always live (the second black *1) and one always dead (the green wire). Assuming the green wire actually is supposed to be a earth, then I still think a fault/short in the controller is keeping the second black wire always live when it should be switched by the heating timer.

 

[OliverHill]

Ok, now I'm really confused.

The second black cable is not always live, it seems to be some kind of inverse to the HW wire. When the HW is on the first black wire is live and the second one off, and when the HW is off the first black wire is off and the second black wire is live. What on earth would that be for. I'm still sure that the CH being on or off makes no difference to any of the voltages on the wires out of the controller.

 

[OliverHill]

All sorted now. I decided to rip the controller off the wall, and found it to open up nicely displaying all the wires and what they were connected to. both the black wires were for HW, one live when on; one live when off as i found earlier (not sure why you'd want a live one when off). Anyway i didn't really do anything but fiddle with it and put it back together. it must have been a simple loose connection as it's worked after i put it back together. Can't believe all the trouble i went to for something which wasn't even broken. Oh well still saved on a plumber call out.