CH on all the time but programed and on automatic

[BobHumphrey]

Having bought a house, I found the old Sunvic mechanical heating timer was not working, so replaced it with a Sunvic 207XLS timer. I have used a Honeywell Sundial Plan Wiring Centre to connect all the various connections.
The system is wired for a Y plan system using:-
Sunvic Room Stat
Sunvic Hot water tank Stat
Danfos HSA3 mid position valve

I have connected:-
Danfos HSA3 Grey to Grey on Mid Posn (on Sundial HW valve connector block)
Danfos HSA3 Blue to Blue on Mid Posn (on Sundial HW valve connector block)
Danfos HSA3 Orange to Orange on Mid Posn (on Sundial HW valve connector block)
Danfos HSA3 Brown/White to White on Mid Posn (on Sundial HW valve connector block)

Sunvic Room Stat Term 1 to 1 (on Sundial Room Stat connector block)
Sunvic Room Stat Term 3 to 3 (on Sundial Room Stat connector block)

Sunvic HW Tank Stat C to C (on Sundial Cyl Stat connector block)
Sunvic HW Tank Stat 1 to 1 (on Sundial Cyl Stat connector block)
Sunvic HW Tank Stat 2 to 2 (on Sundial Cyl Stat connector block)

Boiler which is a Baxi Solo 30/4RS is connected:- L to S/L (on Sundial Boiler connector block)
Boiler which is a Baxi Solo 30/4RS is connected:- N to N (on Sundial Boiler connector block)
Boiler which is a Baxi Solo 30/4RS is connected:- Earth to Earth (on Sundial Boiler connector block)

Pump is conneced to Sundial connector L to L, N to N and Eath to Earth

Sunvic 207 XTS Timer is connected 1 to HW Off (on Sundial Boiler connector block)
Sunvic 207 XTS Timer is connected 2 Not connected as no term in Sundial connector block
Sunvic 207 XTS Timer is connected 3 to HW On (on Sundial Boiler connector block)
Sunvic 207 XTS Timer is connected 4 to CH On (on Sundial Boiler connector block)

On the Sundial connector block I have cut links L1, L4 and L5

The dip switches on the back of the Sunvic 207XLS are set to factory default P, 24hr 7 day, 24 Hr 5/2 day and 2 on/off's So all 4 switched to the Left.

So having done all that everything works fine with the exception that despite having set the Heating and HW to come on at the same time and go off at the same time, the Heating does not switch off with the timer, it is on all the time. It does switch off via the room stat when at Stat temperature though.

HW works fine and switches on and off as required. The mid possition valve appears to be operating as required if the HW is turned off. (The Actuator has also been replaced as the original was old and noisy).

I have tried doing a reset on the Sunvic, but this hasn't resolved the problem.

Has anyone any idea's what could be causing the heating to be running all the time. We are having to control it by the room stat at the moment, which as you can imagine is a bit of a pain. Any constructive help would be appreciated.

 

[seco services]

Danfos HSA3 Brown/White to White on Mid Posn (on Sundial HW valve connector block)

Sunvic 207 XTS Timer is connected 4 to CH On (on Sundial Boiler connector block)

are any of these terminals live when the programmer ch/hw are off on the programmer ?

 

[BobHumphrey]

I am not at the house at the moment, but from memory, when the room stat is turned up (on) and the heating and HW demand turned off on the timer, then Orange on the Danfos valve is live. Normal live to the Stats, pump and boiler are present too. I will have to verify the rest. regards Bob

 

[seco services]

if the stats getting live power then the programmer sounds like its still giving out 230v when the ch is off.

 

[BobHumphrey]

That is true. I guess it could be a faulty timer, but I want to be sure that it isn't somthing else causing the demand before I go down that route. Many thanks Bob

 

[D_Hailsham]

Have you cut the appropriate links on the wiring centre; i.e. L4, L5 and L6?

 

[BobHumphrey]

Link L4 and L5 are cut. I havent cut L6. I only learned today that the boiler supports pump overrun. I will cut this when I am at the house tomorrow. Do you believe this could be my problem?

I will verify all voltages tomorrow should the problem persist.

Many thanks for your time in replying. Much appreciated. regards Bob

 

[BobHumphrey]

Problem is now resolved. It was caused by a faulty Sunvic 207 XLS programmer. This was determined by disconecting HTG ON from the Sunvic and establishing that the Sunvic terminal for HTG ON was always "on"/live. The cause is potentially a faulty relay in the Sunvic. Have now replaced the programmer. Only trouble I now seem to have is getting the defective programmer replaced under warranty by the supplier! but that is another story. Thanks to all those who helped..... Cheers