Honeywell ST9420C User Manual

12
OPERATING YOUR ST9420C
Choosing the Operating Mode (for Heating and/or Hot Water)
The operating mode may only be changed when the slider is set to the RUN position.
The symbol is displayed during a programmed heating on period, and a
symbol is displayed during a programmed hot water on period. A green INDICATOR
LAMP shows when the heating or hot water is switched ON.
Two MODE buttons are provided to select the Operating Mode and therefore how the
heating and hot water are controlled.
Heating has four possible Operating Modes; these are OFF, AUTO, ONCE, CONT.
Pressing the heating MODE button scrolls round these modes in sequence, and the
display indicates which mode is currently active.
• OFF mode
The heating will remain OFF.
• AUTO (Automatic) mode
The heating will be switched ON and OFF according to the heating programme.
• ONCE mode
The heating will come ON at the first programmed ON time, and go OFF at the
last programmed OFF time.
• CONT (Continuous) mode
The heating will remain ON continuously.
The hot water MODE button operates in the same way as described above for the
heating MODE button.
Overriding the Operation Without Changing the Programmes
In AUTO and ONCE operating modes, the OVERRIDE buttons switch the heating or
hot water ON or OFF without altering the programme.
When the
or symbol is displayed, pressing the OVERRIDE button switches
the heating or hot water OFF until the next programmed ON time.
If the
or symbol is not displayed, pressing the OVERRIDE button switches
the heating or hot water ON until the next programmed OFF time.
The LoT™ Display will provide you with information about the override.
HOT WATER HEATING HOT WATER HEATING

Honeywell ST9420C Specifications

General

Model	ST9420C
Category	Thermostat
Display	LCD
Channels	2
Power Supply	230V AC
Mounting	Wall-mounted
Contact Voltage	230V AC
Contact Current	3A resistive, 1A inductive
Switching Type	SPDT
Type	Programmer
Programs	7-day programming
Compatibility	Compatible with most heating systems