Honeywell Y9420H Sundial RF2 User manual

1
Y9420H Sundial RF²Pack 2
INSTALLATION INSTRUCTIONS
50047644-003 A
System Operation
DT92E and ST9420C both use 2-way communication on an 868MHz
radio frequency (RF) band to control the heating and stored hot water
system.
ST9420C operates as the control hub of the system, and DT92E is free to
be positioned anywhere in the living space.
This functionality is ideal for upgrading existing systems without a room
thermostat to ensure compliance with Building Regulations. It is also
ideal for new or refurbished systems, where running mains cable from
the programmer to the thermostat and back to the boiler is difficult or
impractical.
2-way wireless
communication
Honeywell
L641A
Cylinder
Vent
Boiler
V4043H V4043H
Pump
Junction
Box
Radiator(s)
Cold
Feed
DT92EST9420C
L641A
V4073H
DT92EST9420C
Cylinder
Vent
Boiler
Pump
Junction
Box
Radiator(s)
Cold
Feed
L641A
V4044C
DT92EST9420C
Cylinder
Vent
Boiler
Pump
Junction
Box
Radiator(s)
Cold
Feed
L641A
V4043H
DT92EST9420C
Cylinder
Vent
Boiler
Pump
Junction
Box
Radiator(s)
Cold
Feed
S-plan - Best practice, expandable
C-plan - Not for new installations
Y-plan - OK for new installations
W-plan - Not for new installations
Sundial RF²is a registered trademark of Honeywell Inc.
Application
This pack provides a wireless control solution for adding a wireless room
thermostat to an existing Sundial system with wired cylinder thermostat.
Pack contents & Product Descriptions
1 x ST9420C1008 Wireless enabled 7 day programmer with 2 output
control relays for switching boilers, pumps and zone
valves in heating systems. It requires permanent
mains 230Vac power.
1 x DTS92E1020 Wireless digital room thermostat with energy
saving ECO function. It operates on 2xAA alkaline
batteries, giving a battery life of at least 2 years
under typical operating conditions.
1 x table stand for DT92E (optional)
Other Honeywell products may be required for a complete installation.
See Schematic System Layouts (below) or refer to www.honeywelluk.com
for full details.
Schematic System Layouts

2
The RF link between the Room Thermostat (DT92E) and the Programmer
(ST9420C) in Honeywell system packs is pre-configured at the factory
and therefore both units should be installed at the same site.
• Ifproductsfromindividualsystempacksareseparated,ormixed
with other pre-configured system packs during installation, or a
faulty unit is being replaced, the desired units must be specially
configured to allow them to communicate with each other. This
process is called Binding. Please refer to section 5 Binding /
Rebinding Procedure.
• DT92E or ST9420C will not communicate with other RF products
that use different frequencies or communications protocols.
• TheDT92Eroomthermostatrequiresno powersourceotherthan
the batteries provided.
• The ST9420C Programmer requires a permanent 230V~ supply.
• The Programmer should be installed and powered up before
commencing the Room Thermostat installation.
Section Page
1 INSTALLING THE ST9420C PROGRAMMER............ 3
1.1 Mounting ST9420C .................................................................. 3
1.2 Mounting options ..................................................................... 3
1.3 Wiring ST9420C....................................................................... 3
1.4 Final Assembly......................................................................... 3
1.5 ST9420C Internal Wiring.......................................................... 4
1.6 Sundial Plan Wiring Diagrams (S, Y, C, W plans) .................... 4
1.7 Replacement Wiring ................................................................ 5
1.8 Replacing Other Manufacturers’ Time Controls ...................... 5
1.9 Powering Up ST9420C ............................................................ 5
2 INSTALLING THE DT92E ROOM THERMOSTAT ...... 6
2.1 Locating DT92E ....................................................................... 6
2.2 Powering Up DT92E ................................................................ 6
2.3 Signal Strength Test................................................................. 6
2.4 Mounting DT92E ...................................................................... 7
3 SYSTEM CONFIGURATION: ST9420C ..................... 8
3.1 ST9420C Installer Modes......................................................... 8
3.2 Boiler Service Reminder / Shut-down Feature......................... 8
3.3 Installer Setup.......................................................................... 9
3.4 Installer Setup Flowchart ....................................................... 10
3.5 Set Service............................................................................. 10
3.6 Change PIN ........................................................................... 12
3.7 What the User Will See When a Service is Due..................... 12
3.8 Resetting the Service Timer Function.................................... 12
4 SYSTEM CONFIGURATION: DT92E ....................... 13
4.1 DT92E Installer Mode ............................................................ 13
5 BINDING / RE-BINDING PROCEDURE ................... 14
5.1 Binding................................................................................... 14
5.2 ST9420C Guided Binding Menu............................................ 14
5.3 Binding Menu Display............................................................ 14
5.4 Binding Menu Flowchart........................................................ 14
5.5 How to Bind DT92E to ST9420C............................................ 15
6 COMMISSIONING THE SYSTEM............................. 16
6.1 Completion Checklist for Installation ..................................... 16
Within a typical house the two products should communicate reliably
within a 30m range. It is important to take into consideration that walls
and ceilings will reduce the RF signal. The strength of the RF signal
reaching the Programmer depends on the number of walls and ceilings
separating it from the room thermostat, as well as the building construction
- the diagram below illustrates an example of typical signal strength
reduction. Walls and ceilings reinforced with steel or plasterboard walls
lined with metal foil reduce the RF signal significantly more.
RF Signal Propagation
Installation Notes Installation Sequence: Step by Step
Typical example of Building Fabric Signal losses
= Signal Strength
Wall Wall Wall
Ceiling
Max. Signal Length 30 metres

3
For best performance, install in an open space. Leave at least 30cm
distance from any metal objects including pipes and the boiler housing.
If the ST9420C is replacing an existing ST9400 or ST6400 then the
existing wall-plate and wiring may be used, subject to any required
electrical checks.
If the existing wall-plate is mounted on a metal wall-box, the RF
signal performance may be impaired. After locating the DT92E
room thermostat, use the Signal Strength Test shown on Page 6 to
determine if there is a reception problem. If problems persist, it is
recommended that this metal wallbox is replaced by an equivalent
plastic wallbox.
The Programmer should be mounted at a level where the display can be
seen clearly, (compliance with Building Regulations part M requires a height
of 1.2m from the floor) and the ambient temperature is within the range of 0
to 40°C. The ST9420C is for use in normal domestic environments.
To remove the unit from the wall-plate,
slacken the two securing screws at the
bottom of ST9420C and hinge the unit
up to separate the two halves.
Recommended clearance distances:
Above wallplate: 110mm
Below wallplate: 100mm
Left/right of wallplate: 10mm
a. Surface mounting concealed wiring b. Flush switchbox
Fixing holes are spaced to suit
BS4662 requirements
c. Surface mounting with
surface wiring in mini trunking
Clip the unit onto the hinges on the top of the wallplate and hinge down
into position. Tighten the two securing screws using a screwdriver.
Switch on the power – the unit will now be operating according to the
built-in programme.
Note: the ST9420C is supplied with a factory set clock for faster
installation.
Refer to Y9420H User Guide for programming details.
Ensure the mounting surface is supporting and fully covers the wiring wall-plate.
ALL WIRING MUST BE IN ACCORDANCE WITH IEE REGULATIONS.
THIS UNIT IS FOR FIXED WIRING ONLY.
A switch, having contact separation of at least 3mm in all poles must
be incorporated in the fixed wiring as a means of disconnecting the
supply.
The unit is a Class II (double insulated) device. A parking terminal is
provided for external earth continuity.
The system must be appropriately fused. A fuse rated at no more than 3
Amps should be installed.
The unit has 4 knockouts for surface wiring. Care must be taken to
ensure that the cable or mini-trunking completely fills the knockout hole
without leaving any gaps.
EMC compliance considerations
Keep AC mains supply/load cables separate from signal wiring.
Refer to Code of Practice standards EN61000-5-1 and -2 for guidance.
1INSTALLING THE ST9420C PROGRAMMER
1.1 Mounting ST9420C
1.2 Mounting Options
1.3 Wiring ST9420C
1.4 Final Assembly
CAUTION
Isolate power supply and make
safe before wiring the unit to
prevent electric shock and
equipment damage. Installation
should be carried out by a qualified
electrician or competent heating
engineer.

4
Notes
1. DT92E is completely wireless and so is not shown connected on
these wiring diagrams.
2. The ST9420C is a Class II (double insulated) device. A parking
terminal is provided for earth wiring continuity, if required.
3. In the Sundial S-Plan, W-Plan, and Y-Plan wiring diagrams,
connections are shown to basic boilers only. For wiring connections
to Pump over-run boilers refer to Boiler manufacturers’ instructions
or to Honeywell Technical Help Desk for assistance.
4. It is recommended that gravity circulation hot water systems are
fitted with a suitable hot water control valve as shown in the Sundial
C-Plan system.
C-Plan W-Plan
Y-PlanS-Plan
L641
CYL. STAT
2 1
C
V4073
MID-POSITION VALVE
BLUE G/YELLOW WHITE GREY ORANGE
3 AMPS
MAX
L
N
230V~
50...60Hz
BOILER
PUMP
E N L
L
N
E
ST9420C
*NOTE 2
N L1234
12345678910
DT92E
Wireless
Room
Thermostat
DT92E
Wireless
Room
Thermostat
L641
CYL. STAT
2 1
C
V4043H
2 PORT ZONE VALVE
HEATING
BLUE G/YELLOW BROWN ORANGE GREY
V4043H
2 PORT ZONE VALVE
HOT WATER
BLUE G/YELLOW BROWN ORANGE GREY
3 AMPS
MAX
L
N
230V~
50...60Hz
BOILER
PUMP
E N L
L
N
E
ST9420C
*NOTE 2
12345678910
N L1234
Wiring shown as a hot water priority system
Clock
N L 1 2 3 4
3 AMPS MAX
HW OFF HW ON
CH OFF CH ON
N
L
OFF ON OFF ON
230V~
50...60Hz
1.6 Sundial Plan Wiring Diagrams
1.5 ST9420C Internal Wiring
DT92E
Wireless
Room
Thermostat
V4043H
2 PORT ZONE VALVE
BLUE G/YELLOW BROWN WHITE ORANGE GREY
3 AMPS
MAX
L
N
230V~
50...60Hz
BOILER
PUMP
E N L
L
N
E
ST9420C
*NOTE 2
L641
CYL. STAT
2 1
C
N L1234
12345678910
DT92E
Wireless
Room
Thermostat
V4044
DIVERTING VALVE
G/YELLOW BROWN BLUE
L641
CYL. STAT
2 1
C
3 AMPS
MAX
L
N
230V~
50...60Hz
BOILER
PUMP
E N L
L
N
E
ST9420C
*NOTE 2
N L1234
12345678910

5
If using ST9420C to replace other Honeywell Programmers, the equivalent wiring terminations are shown in the tables below.
When converting a fully wired system, remove the wired room thermostat and its associated electrical wiring. Some minor changes are required at the
10-way junction box. These are described in the table below and shown on the wiring diagrams on page 4.
ST6300/ST6400/ST9400 N L 1 2 3 4
ST9420C N L 1 2 3 4
ST699/ST799 N L 3 4 5 6 7 8
ST9420C N L 4 2 not connected 3 1 not connected
ST7100 N L 3 4 5 6 7 8
ST9420C N L not connected 2 4 not connected 1 3
ST9420C Programmers will mount directly onto many existing manufacturers’ back-plates, with a minimal need for re-wiring. They are also supplied
complete with a wiring back-plate, should this not be the case.
Refer to Honeywell Technical Help Desk for wiring conversion diagrams.
Check the unit powers up correctly and that the display does not remain blank.
ST9420C must be powered up before DT92E is installed, so that the signal strength tests can be conducted.
The initial signal strength test will verify that both units have each others addresses in their memory, and can therefore communicate. The process of
writing respective addresses into memory is called BINDING.
1.8 Replacing Other Manufacturers’Time Controls
1.9 Powering Up ST9420C
1.7 Replacement Wiring
Remove links Add links
S-Plan Add wire link from terminal 4 to terminal 5
Y-Plan Add wire link from terminal 4 to terminal 5
C-Plan Remove wire link from terminal 5 to terminal 9 Add wire link from terminal 4 to terminal 9
W-Plan Add wire link from terminal 4 to terminal 7

6
For best performance, install DT92E in an open space where it can
sense the room temperature, and where the signal strength is high.
The Room Thermostat can be mounted on a wall or on the optional table
stand. Do not mount on metal wall-boxes.
Leave at least 30cm distance from any metal objects and at least 1
metre from any other electrical equipment.
Select the preferred location and test the Signal Strength before
installation.
2INSTALLING THE DT92E ROOM THERMOSTAT
2.1 Locating DT92E
DT92E is supplied in the pack with the mounting plate separated from the rest of the unit for ease of installation. The next sequence of operations
should be done before mounting DT92E onto its mounting plate.
First hold DT92E approximately 1 meter from ST9420C. To power it up, unclip the battery cover and then remove the paper tab that isolates the
batteries from their contacts. When the display powers up the battery cover should be clipped back on.
Immediately on power up, DT92E will try to communicate and
synchronise with ST9420C. This process may take up to 4 minutes, and
will be indicated by the word ‘Sync’ on the DT92E display.
When ‘Sync’ disappears from the display, DT92E is ready for a test of
the RF signal strength between it and the ST9420C programmer.
If ‘Sync’ remains on the display for more than 10 minutes, the units
are possibly not bound together. Go to section 5 Binding / Rebinding,
follow the procedure there, then go to section 2.3 to conduct the Signal
Strength Test.
Honeywell 2-way RF communications allows signal strength testing to
ensure DT92E can be positioned in the best possible location.
To enter Signal Strength Test:
a. Hold down the button for 2 seconds until the symbol is
displayed.
b. Hold down the
and buttons together for 3 seconds until ‘Inst’
appears in the display.
c. Press the
button (‘Cont’ is now displayed)
d. Hold the
button for 3 seconds to enter Test mode.
e. Signal Strength Test is entered from Test mode by holding the
button for 3 seconds, until the display shows ‘SS’.
Step 1
Hold DT92E approximately 1 meter from ST9420C and check the signal strength is high (> 2).
This confirms the two units are in the condition they left the factory and are bound together, and
you can move to Step 2.
If the signal strength is shown as 0, the units are possibly not bound together. Go to the
section 5 Binding / Rebinding, follow the procedure there, and then repeat the complete
Signal Strength Test sequence.
Step 2
Whilst staying in Signal Strength Test mode, take the DT92E to the preferred location. Wait for
10 seconds and check the signal strength > 2. If so, the DT92E is ready to mount.
If the signal strength is <2, re-position the room thermostat within the local area +/- 1 or 2m to
see if the signal strength improves. If this fails, try to reduce the range/distance between the
room thermostat and the ST9420C.
2.2 Powering Up DT92E
2.3 Signal Strength Test
✓
✗✗
1.2m
1
2
3 s
2 s
3 s
Poor signal,
reposition Room
Thermostat.
Strong signal,
proceed to
mount the Room
Thermostat.
10 s
= 0, 1, 2= 3, 4, 5
3 s
ST9420C measures the strength of the DT92E signal every 5-10
seconds and will communicate this to DT92E as a number between
0 and 5. The value drops to 0 briefly as each new signal strength
measurement is made.
A signal strength > 2 is recommended to ensure reliable
communications.
Exit Signal Strength Test by holding the button for 5 seconds.The DT92E will timeout of this mode after 10 minutes.

7
DT92E can be mounted (a) directly on a wall, or (b) on the optional table stand provided.
Wall mounting is recommended as it ensures a position of high signal strength can be maintained.
a. For wall mounting, install the mounting plate first, then follow
steps 1, 2 and 3 to hinge the front piece on, as shown in the
diagrams.
b. If the optional table stand is to be used, first assemble the two
pieces together as shown. Next follow steps 1, 2 and 3 to hinge
the DT92E front piece onto its mounting plate, and mount the unit
onto the table stand.
1
2
= No6
3
2.4 Mounting DT92E

8
ST9420C has 3 Installer Modes that enable the product to be customized for the application and for the needs of the User. Each adjustable feature is
called a Parameter, and is represented by a number or letter ID and a value. The Modes are:-
• InstallerSetup
Installer Setup allows features to be adjusted to suit user lifestyles or preferences, for example; backlight operation, automatic time-change, and
selection of the default time programme. It is entered by a combination of button presses.
• SetService
This is where the ST9420C Boiler Service Reminder and Shut-down Features can be set. This mode can only be entered by using a 4 digit PIN
code. The factory supplied default PIN code is 0000
• ChangePIN
This mode allows the 4-digit PIN code to be adjusted. It is itself protected by the PIN code. When the code is changed this new code is used to
enter both SET SERVICE and CHANGE PIN modes.
To Enter & Navigate Around the Installer Modes:
a. Ensure the slider is in the RUN position, then press and hold
and buttons together for 8 seconds. Ignore the ‘NOT VALID’
that is displayed for a few seconds. The message ‘SET UP MENU’
will show briefly, to indicate you have entered the Setup menu. The
LoT™ Display will continue to show messages indicating which
Installer Mode is possible to select, for example ‘SET INSTALLER
OK ?’
b. Use the or buttons to navigate to the correct Installer Mode.
c. Use the button to confirm you wish to enter that particular mode.
To Exit Installer Modes:
You can exit the Installer Modes at any time by moving the slider to the next position and then back again to RUN. Any changes that have been
confirmed will be saved and used.
Note: The Installer Modes and the Setup Menu will exit automatically after 10 minutes if the slider is not moved and no adjustments have been made
in this time.
The ST9420C Programmer has a Service feature that can assist Social Housing Landlords to comply with the requirements of Regulation 36 of the
Gas Safety (Installation & Use) Regulations 1998. It is intended as an aid to compliance but should not be used to replace the Landlord’s existing
Servicing procedures.
The ST9420C performs like a standard programmer. In addition it can automatically provide a Service Reminder and can be set to Shut-down the
heating / hot water system once the gas Boiler Service becomes overdue. This helps to eliminate the potential for an incident to occur after the
Landlord’s Safety Certificate has expired.
The operation of the Service Feature is flexible. The landlord or installer can set the following:
• Theserviceinterval,indays
• Anadvancereminderforthetenant,bycountingdowndaysuntilserviceisdue
• Atelephonenumbertocalltoarrangetheservice–displayedontheLCDscreen
• Howthetimerwilloperatewhentheserviceintervalhasexpired.
The options include:
1. Continued normal operation with a Reminder message
2. Total shutdown of heating and hot water
3. “Prompt” mode – shutdown that will allow repetitive manual over-ride for one hour at a time.
The Service feature is configured from a special Installer Mode called ‘SET SERVICE’. Entry into this mode is only possible by entering a unique 4
digit PIN code.
Note: The ST9420C is supplied from the factory with the Service features DISABLED. They need to be enabled from the Installer Modes. See section
3.5 Set Service for details.
3SYSTEM CONFIGURATION: ST9420C
3.1 ST9420C Installer Modes
3.2 Boiler Service Reminder / Shut-down Feature
Installer Mode LoT™ Display Message
Installer Setup ‘SET INSTALLER OK ?’
Set Service ‘SET SERVICE OK ?’
Change PIN ‘CHANGE PIN OK ?’

9
The wireless system can be set up to operate in a variety of different ways to suit the application, or the user lifestyle or preferences.
This setup is done via the ST9420C Installer Setup. The features that can be adjusted are called Installer Parameters, and are listed in the table below,
along with a description of the options that are possible.
* Only used if CS92A wireless cylinder sensor is connected.
** This parameter by default has a value of 1, unless you change any other parameter, when it will change to 0. Set it to 1 to reset all parameters
back to defaults. Some parameters may not be displayed, depending on the settings made for prior parameters.
INSTALLER PARAMETER Parameter
Number
LoT™ Display
Description
Default
Value
Range of Values Description [LoT™ Display Description]
24hr or am/pm clock display. 1 CLOCK MODE 12 12, 24 12 = am/pm display,
24 = 24hr display
[AM-PM]
[24 HOUR]
Configure backlight
operation.
2 BACKLIGHT 2 0, 1, 2 0 = off,
1 = on if button pressed,
2 = on continuously
[NO B-LIGHT]
[B-L DELAY]
[B-LIGHT ON]
Enable/disable auto time
change.
3 AUTO TIME 1 0, 1 0 = disabled,
1 = enabled
[NO CHANGE]
[TIME CHANGE]
1-day or 5/2-day or 7-day
operation.
4 UNIT TYPE 7 1, 5, 7 1 = 1-day operation,
5 = 5/2-day operation,
7 = 7-day operation
[1-DAY]
[5-2 DAY]
[7-DAY]
Number of ON/OFFs per
day.
5 ON PERIODS 3 2, 3 2 = 2 on/offs per day,
3 = 3 on/offs per day
[2 PER DAY]
[3 PER DAY]
Select default time
programme.
6 DEF PROFILE A A, b, C A = standard,
b = at home,
C = economy
[PROFILE A]
[PROFILE B]
[PROFILE C]
* Set Hot Water Temperature 8 WATER TEMP 50 40 ... 85°C Hot Water Temperature [SET WATER TEMP]
Optimum start 9 OP START 0 0, 1, 2 0 = no optimum start
1 = delayed start
2 = optimum start on
[NO OP-STRT]
[DELAY STRT]
[OP-STRT ON]
Optimum start limit
(Only available if OP START
set to 2)
10 STRT LIMIT 1 1, 2, 3 1 = 1 hour
2 = 2 hours
3 = 3 hours
[1 HOUR]
[2 HOURS]
[3 HOURS]
Optimum stop 11 OP STOP 0 0, 1 0 = disabled,
1 = enabled
[NO OP-STOP]
[OP-STOP ON]
Frost protection temperature 12 FROST TEMP 5 5 to 16°C Frost protection temperature [SET FROST TEMP]
Minimum ON/OFF time 13 MIN ON-OFF 1 1, 2, 3, 4, 5 minutes Minimum ON/OFF time [SET MIN ON-OFF]
Cycle rate 14 CYCLE RATE 6 3, 6, 9, 12 Number of boiler cycles [SET CYCLE RATE]
Proportional band width 15 PROP BAND 15
(=1.5°C)
15 … 30
(=1.5 ... 3.0°C)
Control proportional band [SET PROP BAND]
Failsafe mode (loss of RF
communications)
16 COMMS LOSS 0 0, 1 0 = off
1 = on 20%
[HEAT OFF]
[20 PERCENT]
** Reset all parameters 20 PROG RESET 1 0, 1 0 = do not reset
1 = default parameters
[RESET OFF]
[RESET ON]
To Enter Installer Setup:
a. Ensure the slider is in the RUN position, then press and hold the and buttons together for 8 seconds. Ignore the ‘NOT VALID’ 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 Setup 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 will be saved for use.
e. Press to move to the next parameter available for editing. The parameter number will change accordingly.
f. Keep pressing to step around the list of parameters, and use or buttons to change the parameter value.
g. Any parameter changes that have been confirmed with the button will be saved and used.
To Exit Installer Setup:
You can exit any Installer Mode at any time by moving the slider to the next position and then back again to RUN.
Note: Installer Modes will exit automatically after 10 minutes if the slider is not moved.
3.3 Installer Setup

10
3.5 Set Service
‘SET SERVICE’
PARAMETER
Parameter
ID
LoT™ Display
Description
Default
Value
Range of
Values
Description [LoT™ Display Description]
Enable or disable service
alarm feature
AL SERV MODE 0 0, 1 0 = disabled
1 = enabled
[DISABLED]
[ENABLED]
Number of days till next
Service
d SERV DAYS 364 001 to
400
001….400
000 = service is overdue
[SET DAY COUNT]
Number of days for
advance warning
Ad DAYS NOTICE 28 0 to 28 0 …28 [SET DAYS NOTICE]
Action taken at time-out to ACTION TYPE 2 0, 1, 2 0 = no action,
1 = switch off,
2 = ‘prompt’ mode
[NO ACTION]
[SWITCH OFF]
[PROMPT MODE]
Number of EXTRA HOUR
button presses allowed in
‘Prompt’ mode
bP 1HR BOOSTS uL uL,
1 to 99
uL = unlimited number,
1…99 = specified number of button
presses, after which unit switches off
[NUM BOOSTS]
Enable telephone call
number display
tC SHOW
PHONE
0 0, 1 0 = disabled
1 = enabled
[DISABLED]
[ENABLED]
Enter telephone STD code St STD CODE ------- 1 When a or button is first pressed the LoT™ Display
shows a row of dashes which can be adjusted using or
buttons, then verified using the button.
Enter telephone number nU NUMBER --------- 1 When a or button is first pressed the LoT™ Display
shows a row of dashes which can be adjusted using or
buttons, then verified using the button.
* Reset ‘SET SERVICE’
parameters to default values
rS ALRM RESET 1 0,1 0 = do not reset
1 = default parameters
[NO RESET]
[RESET]
* This parameter by default has a value of 1, unless any other parameter is adjusted, when it will change to 0. Set it to 1 to reset all parameters
back to defaults
Set Service parameters are listed in the table below, along with a description of the options that are possible.
or
LoT™ Display
Parameter
Number
Parameter
Value
3.4 Installer Setup Flowchart

11
To Enter Set Service Mode:
a. Enter Installer Modes (as described on Page
8) and navigate to SET SERVICE mode.
In
response to the query ‘SET SERVICE OK ?’
press the button to enter SET SERVICE.
b. The message ‘ENTER PIN’ will now be displayed,
along with the 4-digit entry code format 0---. The
first digit will be flashing, to indicate it can be
changed. Use the
or buttons to set the
first digit, and press to confirm the digit.
c.
At this point the first digit will stop flashing and
the second digit will begin to flash, indicating it
can be changed.
d. Proceed in this way to enter the 4 digits of the
PIN code. Upon confirming the last digit, if the
PIN was incorrect, the message ‘INVALID’ will be
displayed, and then the whole process will start
again from step b. above.
e. If the PIN was correct, the first SET SERVICE
parameter ‘AL’ will be available to change. This
allows you to enable or disable all the service
alarm features. At every step, the LoT™ Display
will inform you what the parameter means and
what option you have selected. The parameter
ID is usually shown on the display separated by
a colon from the parameter value.
f. 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 will be saved for
use.
g. Press to move to the next parameter available
for editing. The parameter ID will change
accordingly.
h.
Keep pressing to step around the list of
parameters, and use or buttons to
change the parameter value.
i. Any parameter changes that have been
confirmed with the button will be saved and
used . Some parameters may be made invalid by
a previous parameter setting, and these will be
skipped over in the setting process.
To Exit Set Service Mode:
You can exit Set Service Mode at any time by moving
the slider to the next position and then back again
to RUN.
or
or
3.5 Set Service (cont.)

12
If you intend to change the PIN code, please ensure you take a note of the new code that you are setting.
The process for changing the current PIN code is as follows:
a. Enter Installer Modes (as described on Page 8) and navigate to CHANGE PIN mode. In response to the query ‘CHANGE PIN OK ?’ press the
button to enter CHANGE PIN mode.
b. The message ‘ENTER PIN’ will now be displayed, along with the 4-digit entry code format 0---. The first digit will be flashing, to indicate it can
be changed. Use the or buttons to set the first digit, and press to confirm the digit.
c. At this point the first digit will stop flashing and the second digit will proceed to flash, indicating it can be changed.
d. Proceed in this way to enter the 4 digits of the old PIN code. Upon confirming the last digit, if the PIN was incorrect, the message ‘INVALID’ will
be displayed, and then the whole process will start again from step b. above.
e. If the PIN was correct the message ‘SET NEW PIN OK ?’ will appear. As before, use the or buttons to set the digits, and the button to
confirm. Upon confirming the final digit, the message ‘PIN SET’ will be displayed, and the new PIN code will be held on the screen for 5 seconds,
to give you time to note it down.
f. After setting the new PIN code, you will be taken back to the SETUP MENU.
If the advance warning has been configured, the screen will flash this message every few seconds, and the User should
telephone to arrange a service call before the final date when the service is due.
When the boiler service is overdue the screen will keep flashing the words ‘SERVICE DUE’ every second.
If the NO ACTION option has been selected, the unit will continue to operate as normal and the real time will continue
to be shown.
If the SWITCH OFF or PROMPT Actions have been selected, the ‘SERVICE DUE’ message will flash and the word “OFF”
will appear on the display. The boiler has been switched off to ensure the safety of the User. A service appointment
should be arranged immediately.
In PROMPT operation, the User can obtain limited use of the boiler by pressing the HEATING or HOT WATER EXTRA
HOUR buttons. Each button press will allow operation of the boiler for 1 hour at a time, and the screen will display the
message ‘On 1h’, as shown. A service appointment should be arranged immediately.
If a contact telephone number has been programmed into the ST9420C, a message will appear on the LoT™ Display
indicating the number that should be called.
If the Service Timer function is enabled you will be required to reset it after the boiler service has been carried out.
The process for resetting the Service Timer is as follows:
a. Enter Installer Modes (as described on page 8) and navigate to SET SERVICE mode. In response to the query ‘SET SERVICE OK ?’ press the
button to enter SET SERVICE mode.
b. If you no longer require the Service Timer, disable it by setting parameter AL to 0and confirm with the button.
c. If you still require the Service Timer, set the number of days until the next service is due using parameter dand confirm with the button.
d. Whilst in SET SERVICE mode, use the opportunity to change any other service parameters if required.
e. Exit by moving the slider to the next position and back again to RUN.
3.7 What the User Will See When a Service is Due
3.8 Resetting the Service Timer Function
3.6 Change PIN

13
Like ST9420C, DT92E also has an Installer Mode to enable it to be
customized for the application. Each adjustable feature is called a
Parameter, and is represented by a letter ID and a value on the display,
as shown.
The Parameters are listed in the table below:-
To Enter Installer Mode:
a. Hold the button for 2 seconds until
DT92E is in standby mode
b.
Hold and buttons for 3 seconds until
the word ‘Inst’ appears on the display
c. Press the button
The first parameter is now ready to be
changed
To Select a Parameter:
Use the and buttons to move from one
parameter to the next. Stop at the Parameter
you wish to change.
To Change a Parameter:
Use the button to select the parameter
value, then the and buttons to change
the value. Confirm the change by pressing
the button again to take you back to the
parameter.
To Exit Installer Mode:
Hold the button for 3 seconds to exit
Installer Mode.
Note: The Installer Mode will exit automati-
cally after 10 minutes if no adjustments have
been made in this time.
4SYSTEM CONFIGURATION: DT92E
4.1 DT92E Installer Mode
INSTALLER PARAMETER Parameter Default Value Range of Values Description
Temperature measurement offset t0 0 -3 to 3°C Offset to measured temperature
Upper setpoint limit uL 35 21 to 35°C Upper set temperature limit in °C
Lower setpoint limit LL 5 5 to 21°C Lower set temperature limit in °C
Energy saving ECO setpoint ES 18 5 to 35°C Energy saving ECO set temperature in °C
Reset parameters to factory settings FS 1 0, 1 Parameter will be set to 0 if any of the other
parameter values have been changed. Set to 1
to get back to factory settings.
3 s
2 s
3 s
Parameter Value

14
2-way RF devices that communicate with each other achieve this through having each others unique addresses written in their memories. This allows
each device to know which other device to communicate with. The process of writing these addresses is know as Binding.
All devices in the pack are pre-bound at the factory. The binding operation is only required if:
- any of the system components are replaced
- pre-bound system pack components have been mismatched
ST9420C has a special ‘Guided Binding Menu’ that allows you to step through and bind other devices to it in a logical sequence.
NOTE: to bind 2 devices together, BOTH must be put into Binding Mode.
a. Ensure the slider is in the RUN position, then press and hold , and Heating MODE buttons for 8 seconds to access the ST9420C Guided
Binding Menu. The message ‘BIND MENU’ will show briefly, followed by the first binding display.
b. Use the and buttons to select what you want to bind to ST9420C. It is possible to bind different sensors to ST9420C. Each one has a
different binding slot and the Guided Binding Menu helps identify them.
If the display shows dashes it means there is nothing already bound in that slot. If the display shows ‘bnd’ it means there is something already
bound.
c. An existing binding can be cancelled by holding the button for 8 seconds and the LoT™ Display will say ‘RESET’ for a few seconds.
d. Press the button on ST9420C to put it into binding mode for the sensor selected, ready to receive the binding message from the sensor. The
display will flash and the message ‘BINDING’ will be shown to indicate ST9420C is waiting for this message.
e. Put the sensor into binding mode (see section 5.5) and follow instructions to send the binding message to ST9420C.
If the binding was successful, ‘bnd’ will be shown on ST9420C, and the LoT™ Display will say ‘COMPLETE’ for a few seconds. If the binding
was not successful, ST9420C will revert back to its state before the button was pressed after 10 minutes.
f. Repeat steps b. to e. to bind another sensor, ensuring it is the correct type and is bound in the correct slot.
g. Guided Binding Menu can be exited by moving the slider to the next position and then back again to RUN (it will exit automatically after 10
minutes if the slider is not moved).
5BINDING / RE-BINDING PROCEDURE
5.1 Binding
5.2 ST9420C Guided Binding Menu
5.3 Binding Menu Display
5.4 Binding Menu Flowchart
SENSOR : means temperature sensor
Heating (DT92E)
Hot Water (CS92A)
bnd : indicates something is already bound in this slot
-- -- : indicates nothing is currently bound in this slot
Hot Water
Sensor e.g. CS92A
Room Temperature
Sensor e.g. DT92E
/

15
a. Hold DT92E (or its front section, minus mounting plate) approximately 1 metre from ST9420C.
b. Put DT92E into binding mode and reset (clear) any existing binding information as shown.
- Press and hold the button for 2 seconds
- Hold the and buttons for 3 seconds until display shows ‘Inst’
- Press the button and the display shows ‘Cont’
- Keep pressing the button until the display shows ‘CLr’
- Press the button to clear existing binding data
c. Now put DT92E into binding mode by pressing the button again. The display will show ‘COnt’.
d. From the ST9420C Guided Binding Menu, select the Room Temperature SENSOR binding mode shown. This will normally have some device
already bound (indicated by ‘bnd’ in the display). Activate binding by pressing the button.
e. Press the button on DT92E to send the binding message to ST9420C. If binding was successful DT92E will exit binding mode, and will show
‘Sync’ on its display for up to 4 minutes, as communication and synchronisation are established. The ST9420C display will stop flashing, ‘bnd’
will be shown, and the LoT™ Display will say ‘COMPLETE’ for a few seconds.
f. If binding was unsuccessful, repeat steps a. to e. again. If binding was successful, proceed to step g.
g. Exit Guided Binding Menu by moving the ST9420C slider to the next position and then back again to RUN
h. Now go to section 2.3 to verify communication by using the Signal Strength check.
2 s
3 s
5.5 How to Bind DT92E to ST9420C

16
6COMMISSIONING THE SYSTEM
6.1 Completion Checklist for Installation
1Check ST9420C has powered up correctly and the display is not blank. Now set Heating and Hot Water operating
modes to AUTO.
2Check DT92E has powered up correctly and the display is not blank.
3Configure DT92E as required (see Section 4 for how to do this). Remember to make a note of any changes in the
Configuration Data section of the User Guide.
4Change the temperature setpoint on DT92E to 35°C by pressing the button. (If DT92E is currently off, hold the
button for 2 seconds to take it back to run mode).
5Now go to ST9420C. With Heating and Hot Water operating modes set to AUTO, switch Heating and Hot Water on and
off using the OVERRIDE buttons, to ensure the system is operating correctly.
6Check the factory-set day, date, and time are correct and adjust if necessary. Refer to User Guide for details.
7If required, enter Installer Setup Mode and adjust Installer Parameters to match the lifestyle and needs of the User.
Remember to make a note of these parameter changes in the Configuration Data section of the User Guide.
8If required, enter Set Service Mode and enable the Boiler Service Reminder, and set the appropriate Service parameters.
9Set the DT92E to the temperature required by the User (20°C is recommended). Set the cylinder thermostat to the
preferred value (between 50°C and 60°C is typical).
10 Explain the operation of the products to the User, and help them to set their Heating and Hot Water programmes.
ST9420C has 3 built-in profiles that can be used as a basis for typical User programmes.
11 Explain when the User should contact someone to arrange a Service Visit, and what you have programmed to happen
when the Service is overdue.
12 If required, attach the self-adhesive programme guide label to the underside of the ST9420C cover flap. The label is
supplied in the box and requires to be peeled away from the backing material before use.
13 Write the date of installation, your name and telephone number in the space provided in the User Guide, in the section
‘Boiler & System Service Log’.
14 Remember to leave the User Guide and Installation Instructions with the User and remind them to keep them in a safe
place. This forms part of a Home Information Pack.
This product and its associated documentation and packaging are protected by various intellectual property rights belonging to Honeywell
Inc and its subsidiaries and existing under the laws of the UK and other countries. These intellectual and property rights may include patent
applications, registered designs, unregistered designs, registered trade marks, unregistered trade marks and copyrights.
Honeywell reserves the right to modify this document, product and functionality without notice. This document replaces any previously issued
instructions and is only applicable to the product(s) described.
This product has been designed for applications as described within this document. For use outside of the scope as described herein, refer to
Honeywell for guidance. Honeywell cannot be held responsible for misapplication of the product(s) described within this document.
Manufactured for and on behalf of the Environmental and Combustion Controls Division of Honeywell Technologies Sàrl, ACS-ECC EMEA, Z.A. La
Pièce 16, 1180 Rolle, Switzerland, by its Authorised Representative Honeywell Inc.
50047644-003 A
© 2009 Honeywell International Inc.
Honeywell Control Systems Ltd.
Arlington Business Park,
Bracknell, Berkshire
RG12 1EB
Technical Help Desk: 08457 678999
www.honeywelluk.com
®