zone valve issues

[Andymav]

hi guys looking for some technical advice just replaced a drayton ZA5 actuator valve head as when the customer was putting the hot water on they were getting heating aswell the problem ive found is that the valve stays open constantly, when power is cut to the system it closes but when i switch the power back on it opens and doesnt shut so it allows hot water to flow to the heating aswell as the hot water circuit they have a vailiant ecotec boiler and a megaflow pressurised cylinder i cant figure out why the valve doesnt close off the flow to the heating


andy

 

[phil the bucket]

Is the programmer or room stat off on the heating side

 

[Andymav]

yes mate i turned off both sides and the valve stays in open position

 

[kimbo]

Disconect the demand from ythe programmer if it sorts out the problem there is your answer

 

[phil the bucket]

Is the zone valve a normally open ,or a normally closed one should say on it

 

[Andymav]

it says on the manual they are supllied in the closed postion and have to be powered to open and they spring to the closed position when power is removed its a2 port valve

 

[Chalked]

Not the best valve in the world, did you just replace the head or complete valve?

Could be a sticking valve body

 

[mountainman]

Have you a multimeter and know how to use it?

 

[Andymav]

well i took off the head and the valve itself is turning fine and freely it just seems like its not closing despite the fact it is turning ok its weird as hell

 

[Andymav]

i have a multimeter mountainman yes

 

[Ermintrude]

Turn off timer and stats so there is no demand for heat. Take cover off zv. The two wires coming to motor carry power and open Valve.

In accordance with manufactured instructions set up your multi meter to work on 240v. Put one lead on to a neutral wire in connector block and then test either of the wires to the motor. If one of them is live its the wrong wire. Take a picture of zv wires and pic of wires in box

 

[mountainman]

When the valve is stuck open, is there power on the brown wire?

If so then a control is keeping the valve open, if not then the valve is most likely faulty.

Disconnect the brown and the valve should close, if not then it's burglered.

 

[Ermintrude]

Next u need to determine which wires are coming from your controller and which is live and which is s/l for zones

 

[mountainman]

Turn off timer and stats so there is no demand for heat. Take cover off zv. The two wires coming to motor carry power and open Valve.

In accordance with manufactured instructions set up your multi meter to work on 240v. Put one lead on to a neutral wire in connector block and then test either of the wires to the motor. If one of them is live its the wrong wire.

Are you sure?

 

[Andymav]

yes there seems to be power flowing through it which tells me that something is telling it to stay open

 

[Ermintrude]

Are you sure?

Hope so, if no demand and testing to neutral then the valve shouldn't be energised and will probably read 350mV

 

[phil the bucket]

Check room stat and programmer suspect it could be room stat

 

[Ermintrude]

yes there seems to be power flowing through it which tells me that something is telling it to stay open

You have connected a perm live to it so as others said check timer is off. Put timer on and test room stat, put on room stat, test across s/l and neutral - small voltage difference, now turn stat to 10c should have big diffrrnce 180v or more. Do same on cylinder stat . If they both break and make circuit turn both to low (no demand) check again at motor for voltage. If no voltage then u have a faulty time switch. If you have voltage u made a boo boo and connected one wire to perm live.

 

[Chalked]

Could you have the brown and grey wires crossed to the wrong connections? The grey is live when mains are on and would then back feed and keep the valve open

 

[kimbo]

As the problem was there before the new valve wss fitted it would be logical to assume that it is not the wiring or the valve at fault more likely to be the programmer or possibly stat.

 

[Ermintrude]

As the problem was there before the new valve wss fitted it would be logical to assume that it is not the wiring or the valve at fault more likely to be the programmer or possibly stat.

How would stat bring in hot water if wired correctly? Perhaps timer wired incorrectly ? Easy way to check is remove wires for heating and hot water from back plate on timer and re test?

 

[phil the bucket]

How would stat bring in hot water if wired correctly? Perhaps timer wired incorrectly ? Easy way to check is remove wires for heating and hot water from back plate on timer and re test?

The problem is the heating zone valves your just complicating matters

 

[kimbo]

Disconect the demand from ythe programmer if it sorts out the problem there is your answer

As stated earlier check heating demand from programmer disconnect heating on wire and see if valve still opens which would indicate a back feed. If it doesnt I would go for the programmer

 

[Andymav]

it would appear that yes the zone valve wasnt the problem originally i would assume the programmer is the problem, the system is quite new as the houses are new builds and the wiring centre is wago connectors il include a picture the wiring is exactly as it was i have double checked my wiring and it seems ok so im assuming the programmer has developed a fault

 

[mountainman]

You have connected a perm live to it so as others said check timer is off. Put timer on and test room stat, put on room stat, test across s/l and neutral - small voltage difference, now turn stat to 10c should have big diffrrnce 180v or more. Do same on cylinder stat . If they both break and make circuit turn both to low (no demand) check again at motor for voltage. If no voltage then u have a faulty time switch. If you have voltage u made a boo boo and connected one wire to perm live.

Why 180v?
Mains voltage is usually 230 to 240v.
This is really basic stuff imo and if as suggested, the op has made a boo boo, then perhaps it's time to call a professional to sort it out.

 

[ManchesterGas]

180v difference as you will usually get around 50v when it's at rest

 

[mountainman]

Not on any zone valve that I've ever encountered.
Check the recent 'S' plan thread on this forum.

 

[Andymav]

 

[Andymav]

 

[Andymav]

it cant be a wiring issue because the valve was wired the same way exactly so im assuming this vault has developed

 

[mountainman]

Nice piccie, I prefer Honeywell valves though, expensive but quality.

 

[Chalked]

it cant be a wiring issue because the valve was wired the same way exactly so im assuming this vault has developed

I would bet as this is a new propery the fault is wiring and has been there all the time.
Like others have said check that grey is live with the mains on and when calling for heat the brown becomes live. Also check the brown does not become live when other valves are calling. This would indicate a back feed.
a picture inside the junction box would be helpfull

 

[Andymav]

so you believe the zone valve itself maybe wired incorrectly

 

[phil the bucket]

I would bet as this is a new propery the fault is wiring and has been there all the time.
Like others have said check that grey is live with the mains on and when calling for heat the brown becomes live. Also check the brown does not become live when other valves are calling. This would indicate a back feed.
a picture inside the junction box would be helpfull

Could be a loose wire in the jb have u asked the customer if this has just started to happen or has always happened

Is the heating system getting luke warm or hot

Is it the rads in the bathroom just getting hot

 

[SimonG]

Pull it out and wire from scratch. That way you know the wiring is correct and then go from there.