The Way To Use A Room Thermostat / Control Of Your Boiler / Optimisation - Honeywell Y9520Z Sundial RF2 Pack 5 User Manual

CONTROL OF YOUR SYSTEM
A typical use of the EXTRA HOUR button would be if you returned to the house for
a short period when the heating was off. Pressing the appropriate EXTRA HOUR
button gives you 1, 2, or 3 hours of heating, exactly when you need it. Another typical
use is when the heating is already on and you want it to stay on a little longer - just
press EXTRA HOUR and, for that day only, an hour will be added to the end of the
time at which heating normally goes off.
The MODE buttons allow you to select how you want to operate the heating in each
zone independently. The most obvious use is to switch heating OFF during the
summer months, but you may also use this feature if you take a mid-week day off
work, you can then set the MODE to ONCE to keep the system ON during the day
from the first programmed ON time till the last programmed OFF time.
The way to use a Room Thermostat
The way to set and use your room thermostat is to find the lowest temperature setting
that you are comfortable with, and then leave it alone to do its job. The best way to do
this is to set the room thermostat to a low temperature – say 18°C – and then turn it
up by one degree each day until you are comfortable with the temperature. You won't
have to adjust the thermostat further. Any adjustment above this setting will waste
energy and cost you more money.
DT92E has a green ECO button, which enables you to set a period of time at a lower
temperature. This energy saving feature is most useful if you are out of the house
for a few hours, or if you want a reduced temperature for a while and don't want to
have to remember to turn the temperature back up (see pages 22 & 23 for details).
Control of Your Boiler
There are several ways your boiler may be controlled. It may be switched directly
using the ST9520C timer. If installed in a remote location, it may be switched using a
BDR91T relay box. If your boiler supports the OpenTherm communications system,
it may be connected to the ST9520C timer by OpenTherm wiring, over which the
control information is sent.
In each situation the operation of the boiler is determined automatically by the
combination of inputs from the room thermostat and the timer, and in such a way as
to maintain your comfort with minimal energy use. The timer will indicate the on/off
status of the boiler by showing the flame symbol .
Optimisation (see page 17 for explanatory diagrams)
Your control system has some features called Optimisation, which aim to save
energy while making you as comfortable as possible. These may or may not be
enabled – check page 34 where your Installer should have indicated how these
were set. Optimisation does not apply to your Hot Water, only to your Heating.
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