Y plan heating stays on when programmer is turned off

[Connor Williams]

Hello guys here's a problem I am having and would appreciate any helpful advice thankyou.
i have a Honeywell Y plan heating system with three port zone valve and the heating and hot water stays on when the programmer is turned off.
i have renewed the programmer and the problem is still happening.
when I turn down the cylinder stat and wall stat this will turn off the pump and boiler.
So....I suspect the zone valve may be sticking but how does this explain a constant electrical signal going to the valve, only interrupted by the stats being turned off.
got me stumped as I have renewed the programmer and it's made no difference, any advice greatly appreciated thanks

Connor

 

[sedgy34]

Sounds like a wiring issue

 

[Kay101]

Hello guys here's a problem I am having and would appreciate any helpful advice thankyou.
i have a Honeywell Y plan heating system with three port zone valve and the heating and hot water stays on when the programmer is turned off.
i have renewed the programmer and the problem is still happening.
when I turn down the cylinder stat and wall stat this will turn off the pump and boiler.
So....I suspect the zone valve may be sticking but how does this explain a constant electrical signal going to the valve, only interrupted by the stats being turned off.
got me stumped as I have renewed the programmer and it's made no difference, any advice greatly appreciated thanks

Connor

power on the Orange wire coming from the three port, I suspect the fault is in the three port, when programmer off there should be no power on orange, it can get power from the grey to the three port but shouldn't, if you know what your doing you could check this out. Only check if your safe and know what your doing, don't touch without safety electrical knowledge

 

[Leo21]

Get a professional in, its safer.

 

[Kay101]

Agreed Leo, I was assuming the op is a professional but couldn't find the fault, if not a professional get one in

 

[Connor Williams]

Thanks for the replies, yes I have carefully checked with my mains tester and there is power on the grey and orange wires even when the programmer is turned off.
i thought the valve may be stuck but when I turn off the cylinder stat and room stat this does shut everything off and the 3 port valve does close off the heating port into its 'standby' position.
this is the only way to shut off the boiler and pump at the moment.
So maybe I should replace the actuator and take it from there!

 

[Kay101]

Think the actuator may be fine, it sounds like the internal wiring in the head, or it could be wired wrong sending power out on orange, need to check every piece of wiring if safe to do so

 

[Connor Williams]

Thanks guys don't worry I am a professional plumber but have to confess this had me stumped a bit but the customer has just informed me this has only started since a previous plumber renewed the pump two weeks ago and won't come back.
hmm....reckon he may have got his wiring wrong, I will check the wiring and let you know the end result thanks for your help.

all the best Connor

 

[Leo21]

My apologies Connor, I didn't know you were trade. It sounds like a wiring fault, the easiest way forward to my mind would be to wire a new divertor in, without actually doing the wet side to test the theory.

 

[Connor Williams]

No problem as we are dealing with electrics so I appreciate we have to be careful with advice given. I will double check the wiring but I doubt the previous plumber altered the wiring in the junction box as pumps don't normally come with a flex, I normally just disconnect and reconnect at the pump terminals.

i will doublecheck all wiring, renew the actuator and post the outcome thanks again for your help,
all the best Connor

 

[DaveTidy]

If the wirings fine then you'll need to change the actuator as the mircroswitch has gone and they can't be replaced.