MINI-PROGRAMMER OPERATING INSTRUCTIONS
You need only refer to this section if:
• The Mini-Programmer box is ticked on the Contents page of this booklet, or
• The ST9400A Configuration Data (page 18) indicates it is set as a Mini-
Programmer.
What is a Mini-Programmer?
In a poorly controlled gravity circulation hot water system, whenever the boiler
comes on to service the heating, there will inevitably be some circulation though the
hot water storage tank, which will then heat up.
So, whenever the HEATING is ON, the HOT WATER is also ON.
It is therefore NOT possible to have independent programmes for heating and hot
water, so it is only necessary to enter one time programme.
If you have this type of installation (gravity circulation hot water circuit WITHOUT a hot
water control valve), your Installer should have restricted the ST9400A Programmer
to be a Mini-Programmer.
This section describes how to use the product as a Mini-Programmer.
Modifying the Heating & Hot Water Programme
The heating & hot water programme has three pairs of ON/OFF switching times per
day. Each time can be set between 3.00 am and 2.50 am (on the next day) to allow
you to programme the heating & hot water to stay on past midnight, if required.
a. Move the slider to the HEATING position. ‘SET HEATING’ will show briefly to
verify this action.
b. Now follow the same procedure to set the times as described in ‘Modifying the
Hot Water Programme’ (page 7) steps b to e.
Exiting Heating & Hot Water Programming Mode:
To exit HEATING Programming mode, move the slider to the RUN position. This can
be done at any time during the programming process, and any changes made and
confirmed with the button will have been saved.
Note: If the unit is left in HEATING Programming mode for more than 10 minutes
without the slider being moved or any buttons pressed, the message ‘MOVE SLIDER’
will be displayed. Press a button to finish programming, or move the slider to the
RUN position.
