Honeywell ST9420C User Manual

16
To Enter Installer Mode:
a. Ensure the slider is in the RUN position, then press and hold
and buttons
together for 8 seconds. Ignore the ‘NOT VALID’ message that is displayed for a
few seconds. The message ‘SET UP MENU’ will show briefly, followed by ‘SET
INSTALLER OK ?’
b. Press the
button to take you into the Installer Mode Parameter Menu.
c. Parameter 1 is now available to change. This is to allow you to change the
clock format from 12 hour AM/PM to 24 hour. At every step, the LoT™ Display
will inform you what the parameter means and what option you have selected.
The parameter number is shown on the display separated by a colon from the
parameter value.
d. You can change the parameter value by pressing the
or buttons. At this
point the description in the LoT™ Display will change and the parameter value
will flash. If you press the value will stop flashing and be saved for use.
INSTALLER
PARAMETER
Parameter
Number
Default
Value
Options Description
Optimum start 9 0 0, 1, 2 0 = no optimum start
1 = delayed start
2 = optimum start on
* Optimum start limit 10 1 1, 2, 3 1 = 1 hour
2 = 2 hours
3 = 3 hours
Optimum stop 11 0 0, 1 0 = disabled
1 = enabled
Frost protection
temperature
12 5 5 to
16°C
Frost protection
temperature
Minimum ON/OFF
time
13 1 1, 2,
3, 4, 5
mins
Minimum ON/OFF time
in minutes
Cycle rate 14 6 3, 6, 9,
12
Number of boiler cycles
per hour
Proportional band
width
15 1.5 1.5 to
3.0°C
Width of control
proportional band in °C
Failsafe mode (loss of
RF communications)
16 0 0, 1 0 = off
1 = heating on 20%
Reset all parameters 20 1 0, 1 0 = do not reset
1 = default parameters
FINE TUNING YOUR ST9420C

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