Problem with a Sundial Y Plan system

[Piratepete]

Hi
I'm investigating a Fully pumped Honeywell Sundial Y plan system with a mid position zone valve. The customer only had hot water.

I found that the motor on the valve was knackered and changed it. I also had to replace the Sundial Wiring Centre and swopped the wiring over one for one (I think).

The problem now is that though there is now hot water and heating with the thermostats seeming to operate correctly, the programmer won't turn off the system once it switches on.
It seems clear to me that there is feedback from somewhere which latches the circuit permanently 'on'. I've checked the connections and all seems ok. Can it be another fault in the valve - switches or circuit board doing this? I don't fully understand when the 2 microswitches operate.

Getting desperate.

Pete :cry_smile:

 

[ajelec10]

From memory I think you require a special wiring centre with a built in relay? I always stick with Honeywell spring return valves!

Hope this helps??

 

[itselectric]

Honeywell Y-Plan Explanation
the above website shows animated actions of circuit diagram. Hope it helps.

 

[ajelec10]

The op mentions sundial not Honeywell these valves work differently and I don't think they even have micro switches built in. But with out part numbers it's hard to identify.

 

[itselectric]

The op mentions sundial not Honeywell these valves work differently and I don't think they even have micro switches built in. But with out part numbers it's hard to identify.

oops sorry. no help then.

 

[tanna]

If u have Iphone download Honeywell wiring systems app, a plumber showed me it and i can't believe how helpful it is!

 

[ajelec10]

If u have Iphone download Honeywell wiring systems app, a plumber showed me it and i can't believe how helpful it is!

Still no help its sundial not honey well!

I had the same problem and you will require a really to stop the back feeding problem. Sundial of a special wiring centre with the relay built in. Thinks its about a oner though!

 

[Piratepete]

Honeywell Y-Plan Explanation
the above website shows animated actions of circuit diagram. Hope it helps.

Thanks, yes it should help. Also found a schematic and description of how the valve works. If I can't faultfind with all this info, I'm becoming a chippie!

 

[Piratepete]

The op mentions sundial not Honeywell these valves work differently and I don't think they even have micro switches built in. But with out part numbers it's hard to identify.

Um. As far as I know Honeywell and Sundial are all the same.

 

[Piratepete]

Tis a Honeywell valve.

 

[ajelec10]

Good luck Pete! Can't remember what the make of valve was I had may have been danfoss but it was a night mere even the two port zone valves don't have micro switch or spring return you have to use the no contact of the stat to open valve and nc to close!!! Honeywell all the way!!