Sundial wiring centre/Tempus 7 issue

2 Dec 2010
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United Kingdom
Boiler Worcester Danesmore 15/19, Honeywell 2 wire tank stat, Honeywell DT90 roomstat, Drayton Tempus 7 controller And Honeywell sundial wiring centre.
It's wired C Plan ( gravity HW with 2 port valve, pumped CH)
I guess the issue is either the programmer wiring or the valve wiring. The six wires from the valve are wired like for like to the sundial, likewise the Tempus 7 with the exception of the CH off wire which is not connected (on advice).
The boiler fires up and closes as per the timer and both neons light up and both appear to be functioning i.e water and rads heating but only CH displays the off time. Boost on water doesn't work, boost on CH does but also lights HW neon so I assume is doing water as well.
In winter not an issue but need to have water only in summer. Any advice greatly received, Thanks
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You have not really explained what the issue is and if it has suddenly appeared.

Nor have you told us what make and model of motor valve you have.

I would be quite surprised if the system is really designed to allow the boiler to provide gravity hot water on its own. That would result in very excessive short cycling.

A very useful improvement would be to convert it to pumped HW.

Me thinks you need to check the wiring
The two light on programmer should not come on when CH selected

Boiler should fire for hot water
Boiler and pump run for CH
Programmer set on gravity when it should be set on fully pumped ?
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Programmer set on gravity when it should be set on fully pumped ?
Booster on HW foes not work.
Picasso, would you agree with programmer in gravity mode, the boost button should work?
If wiring ok, then has to be the programmer

Would check supply fuse as well as often 13amp fuse in place of 3 amp, which often kills the programmer if there is a short circuit
Ok just to give a bit more background. It's on a 3 amp spur and yes(and no) its suddenly appeared I'll explain more. The system was installed in the 60's or maybe 70's the existing timer was electro mechanical (not danfoss Randall dial type think older more like a street light timer switch) This did not function i.e the timer dial did not rotate but the wiring still went via it. The boiler was plugged into a socket with an off the shelf pin type lamp timer. The central heating pump was wired to a switched socket and in winter simply switched on to pump water round the radiators. Yes HW was gravity only. All this contraption was wired via a Honeywell 10 block connection centre. This has now been replaced as per my original question so the problem is sort of suddenly but in the sense of suddenly developing a fault.
Aha, checked with Drayon technical staff before fitting Tempus 7 and was told to set programmer to Gravity.
So much for advice from the source! Thanks to all who responded

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