Honeywell Sundial RF Pack 4 Wireless Enabled Timer and Cylinder Thermostat User Manual

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FAQ  AND TROUBLESHOOTING
How do I set the time only, if the ST9120C clock is not correct?
Your ST9120C contains an accurate digital clock that is factory set. Should you ever 
need to change the time, just follow this procedure:
a. Move the slider to the DAY/TIME position.
b.  Keep pressing the green 
 button until the message ‘SET THE TIME’ is 
displayed. To change the time, press the   or  buttons until the correct 
time is shown. The message ‘IS TIME OK?’ will be displayed. Press the green  
button to confirm the time is correct.  If you have made a change, the message 
‘TIME SAVED’ will show, followed quickly by ‘DATE + TIME COMPLETE’.
c.  Move the slider to the RUN  position, to complete changing the time.
What do I do when the clocks go back in October and forward 
in March?
Your ST9120C is factory set to change the clock automatically at the correct dates, 
so you should never need to adjust the clock forward or backwards yourself. It is 
possible to disable this particular feature, as described in the section ‘Changing the 
Installer Parameters’ (page 15). You may also check the section ‘Configuration 
& Service Data’ (page 26) to see how your Installer has configured your product.
What should I do if I get ‘lost’ while programming the ST9120C?
The LoT™ Display on ST9120C will provide you with help and tips to work through 
the programming. Should you ever get ‘lost’, the simplest thing to do is\
 to move the 
slider to the RUN  position, and then move it back to the appropriate programming 
position where you got lost. At this point just follow the instructions again.
What happens if there is a power failure?
In the event of a mains power failure, the ST9120C display will go blank, the 
indicator lamps will go out, and the control outputs will switch off. The real time 
will be constantly maintained by means of the built-in battery backup, ready to 
power back up as if nothing had happened when the mains power is restored. In 
addition, all programmes and settings are stored in a special memory (called Non 
Volatile  memory) which requires no power to maintain information so will be retained 
indefinitely.
Should the correct time and date ever be lost, for whatever reason, the message ‘SET 
DATE + TIME’ will be displayed whilst the slider is in the RUN  position. In this case, 
simply follow the procedure described under ‘Step 1: Setting the Date & Time’ 
(page 6). It should not be necessary to make any changes to your programmes. 
						

							22
FAQ  AND TROUBLESHOOTING
How reliable is 2-way RF communication?
The 2-way RF communication (also known as wireless communication) used by 
Honeywell is extremely robust and reliable. When installed correctly the Signal 
Strength test feature allows the Installer to locate the system components where 
mutual signal reception is strong. During communication, signals are sent several 
times to ensure receipt, and if any message is garbled, the error detection software 
recognises this and ensures the message is repeated again.
What do I do if RF communication is lost?
Follow the steps in the Troubleshooting Guide on the next page. The most likely 
cause for loss of communications is the CS92A batteries running low on p\
ower. This 
will be indicated on CS92A, as described on page 19. Simply replace the batteries 
(as shown on page 19) and wait a few minutes for communications to bec\
ome re-
established.
If this does not resolve the problem it may be that the RF signal path between 
the ST9120C and the CS92A is blocked by a metal object. Check the direct path 
between the two devices and reposition any object that may be blocking the signal, 
or move the thermostat.
How do I know when to change the batteries in the CS92A 
cylinder thermostat?
If the CS92A batteries need changing, ST9120C will show the message ‘\
SENSOR 
LOW BATT’ and the tap symbol  will flash. . You can confirm this by pressing the 
CS92A button, whereupon the red light will give a brief flash every second to indicate 
a low batter y state. It is important to change the CS92A batteries as soon as the low 
battery condition is indicated, as reduced battery power may affect the RF signal 
strength and impair RF communications. 
						

							23
FAQ  AND TROUBLESHOOTING
Troubleshooting Guide
This is a quick guide to help you diagnose and cope with possible problems with 
your wireless control system. For further assistance, please contact your Installer.
SymptomPossible CauseRemedy
ST9120C has a blank 
LCD display No power to the 
heating systemCheck that there is power to the 
heating system
Fault in ST9120C
Call Installer
ST9120C indicates the 
system is ON, but taps 
are running with cold 
water.
Temperature controls 
are switched off or 
set too lowCheck that the temperature controls in 
the system are set to appropriate levels
Boiler or other 
system controls 
have malfunctioned Call Installer
ST9120C shows the 
message: 
‘INTERNAL FAULT’ Fault in ST9120C
Call Installer
Every few seconds, the 
ST9120C screen shows 
the message:  ST9120C is counting 
down the number of 
days until your next 
boiler service is due.Arrange a boiler service before the 
counter reaches zero.
After servicing your boiler, the Service 
Engineer / Installer will reset the 
ST9120C to remind you when the next 
boiler service is due. Each service is 
normally a maximum of 1 year apart.
Although the heating 
is still operating, the 
ST9120C screen keeps 
flashing the message:Your boiler service is 
overdue.
Arrange an immediate boiler service.
After servicing your boiler, the Service 
Engineer / Installer will reset the 
ST9120C to remind you when the next 
boiler service is due. Each service is 
normally a maximum of 1 year apart.
The ST9120C screen 
shows the message: Your boiler service 
is overdue and 
the boiler has 
been automatically 
switched off to 
ensure your safety.Arrange an immediate boiler service.
If set to do so, it may be possible to 
obtain limited use of the boiler by 
pressing the EXTRA HOUR button. 
Each button press will allow operation 
of the boiler for 1 hour at a time, and 
the screen will display the message 
‘On 1h’.
After servicing your boiler, the Service 
Engineer / Installer will reset the 
ST9120C to remind you when the next 
boiler service is due. Each service is 
normally a maximum of 1 year apart. 
						

							24
SymptomPossible CauseRemedy
ST9120C shows the 
message ‘SENSOR LOW 
BATT’ and a flashing tap 
symbol CS92A batteries 
are running low on 
power Change the CS92A batteries (see page 
19 for how to do this)
CS92A battery low 
indication (press CS92A 
button and red light 
gives a short flash every 
second 0.1s on, 0.9s off. 
Note: light will switch off 
after approx 1 minute to 
save battery power)
ST9120C shows the 
message ‘NO SIGNAL’ 
and a flashing tap 
symbolCS92A batteries are 
running low on powerChange the CS92A batteries (see page 
19 for how to do this)
RF communication 
path between 
ST9120C and 
CS92A is blocked, 
possibly by a 
metal object Check direct path between both 
products and re-position any objects 
that may be blocking the signal
Relocate the CS92A transceiver, if 
possible
ST9120C shows the 
message ‘SENSOR 
FAULT’ and a flashing 
tap symbol 
 
CS92A sensor error 
indication (Press 
CS92A button and red 
light blinks 0.5s on, 
0.5s off. Note - light will 
switch off after approx 
1 minute to save 
battery power CS92A sensor 
cable may be 
disconnected 
from the wiring 
terminals
Re-connect the sensor wires to the 
CS92A terminals
Fault with CS92A Call Installer
Troubleshooting Guide (cont.)
FAQ  AND TROUBLESHOOTING 
						

							25 
						

							2650047645-002 A
CONFIGURATION & SERVICE DATA
Configuration Data (to be completed by Installer)
The tables below are for the Installer to complete to indicate how your ST9120C has 
been configured.
Application
Insert application number as per Installation wiring diagrams:
Configurable FeaturesOptionsFactory 
settingInstaller configured 
(tick box or note value)
ST9120C Configuration - standard
24hr or am/pm clock 
display. am/pm display
24hr display
Display backlight operation. Off
on if button pressed
on continuously
Automatic time change.disabled,
enabled
1-day or 5/2-day or 7-day 
operation.1-day operation
5/2-day operation
7-day operation
Number of ON/OFFs per 
day.2 on/offs per day,
3 on/offs per day
Default time programme.
A = standardb = at home
C = economy
Hot water set temperature From 40 to 85°C60°C
Optimum start no optimum start
delayed start
optimum start on
Optimum start limit 1 hour
2 hours
3 hours
Optimum stop disabled
enabled
Frost protection temperature From 5 to 16°C5°C
Minimum ON/OFF time 1, 2, 3, 4, 5 minutes1 minute
Cycle rate 3, 6, 9, 12 cycles 
per hour6 cycles
Proportional band width From 1.5 to 3.0°C1.5°C
Failsafe mode (loss of RF 
communications) off
on 20% *
* This option will not operate on a hot water only system