Getting Started With Your St9420C; Step 1: Setting The Date & Time - Honeywell Y9420S User Manual

CONTROL OF YOUR SYSTEM
using this to calculate the correct time to switch on to reach your comfort temperature,
when you want it. So the times you set are when you want the heating to be at
the correct temperature, and the system adjusts the starting time to meet this.
Delayed Start is an alternative to Optimum Start. It works by using your normal
programmed start times, compares the actual temperature with the set temperature, and
delays the start a little depending on how close these temperatures are to each other.
Optimum Stop saves energy, and money, by switching off a little earlier than the
normal programme time. If the house is up to temperature, you will not notice the
effect on the temperature, but you will see a difference in your fuel bill.
The radiator symbol on ST9420C will flash to let you know whenever Optimisation
is operating.
The other controls in your system should not require adjustment.

GETTING STARTED WITH YOUR ST9420C

Your ST9420C should have been set up to work correctly when it was installed.
However, the following will show you how you can modify your settings to meet
your particular lifestyle.
To assist you with programming and everyday use your ST9420C will display text
messages at every stage to help you get the most out of your central heating and hot
water system. The ST9420C uses LoT™ Technology to constantly update the display
to give you feedback about what is required.
Step 1: Setting the Date & Time
Your ST9420C had the date and time set at the factory, and these are normally
maintained by a backup battery in the event of power failures. If you wish to change
the date or time, or if the LoT™ Display shows the message 'SET DATE + TIME' just
follow the instructions below. Otherwise, go to Step 2.
a. Move the slider to the DAY/TIME position. The message 'SET DATE + TIME' will
show briefly on the screen, followed by 'SET THE DAY', and the day of the month
will now be flashing to indicate it can be changed.
DAY/TIME
HOT WATER
HEATING
RUN
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HOT WATER HEATING