homexpert THR842DUK User manual
User Manual
THR842DUK Wireless
Digital Thermostat
50051983-001 Rev. A
homexpert
tm
by Honeywell THR842DUK Wireless Digital Thermostat
3
About your new thermostat
What is a room thermostat? ..................4-5
QUICK START GUIDE............................. 6
Quick reference to controls....................... 7
Operation
On/off switch ............................................ 8
Heating or cooling control......................... 9
Temperature control................................ 10
Energy-saving ECO mode ......................11
Installation and setup
System installation .................................. 12
Relay box installation .............................. 13
System wiring....................................14-15
Battery installation & testing...............16-17
Thermostat installation.......................18-19
System test ............................................ 20
Installer setup ....................................21-25
Appendix
In case of difficulty .............................26-29
Warranty information............................... 30
Declarations, disposal & recycling........... 31
Contents
NOTE: This symbol will flash on the screen
when battery power is low. Remove cover and
replace batteries with two fresh AA alkaline
batteries (see page 16).
WARNING: This product must be correctly installed and configured to work properly (see
pages 12-23). If you are not experienced in wiring electrical equipment, we recommend
professional installation to avoid possible personal injury or equipment damage.
TIP: After installation, see the QUICK START GUIDE on page 6 to customise and begin using
your new thermostat right away.
Copyright © 2010 Honeywell International Inc.
homexpert
tm
by Honeywell is a trademark of Honeywell International Inc. All rights reserved.
®
User Manual
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homexpert
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by Honeywell THR842DUK Wireless Digital Thermostat
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...an explanation for householders
A room thermostat simply switches the heating system on and off as necessary. It works
by sensing the air temperature, switching on the heating when the air temperature falls
below the thermostat setting, and switching it off once this set temperature has been
reached. Turning a room thermostat to a higher setting will not make the room heat up
any faster. How quickly the room heats up depends on the design of the heating system,
for example, the size of boiler and radiators.
Neither does the setting affect how quickly the room cools down. Turning a room thermostat to a lower setting
will result in the room being controlled at a lower temperature, and saves energy.
The heating system will not work if a time switch or programmer has switched it off.
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.
What is a room thermostat?
If your heating system is a boiler with radiators, there will usually be only one room thermostat to control the
whole house. But you can have different temperatures in individual rooms by installing thermostatic radiator
valves (TRVs) on individual radiators. If you don’t have TRVs, you should choose a temperature that is
reasonable for the whole house. If you do have TRVs, you can choose a slightly higher setting to make sure
that even the coldest room is comfortable, then prevent any overheating in other rooms by adjusting the TRVs.
Room thermostats need a free flow of air to sense the temperature, so they must not be covered by curtains
or blocked by furniture. Nearby electric fires, televisions, wall or table lamps may prevent the thermostat from
working properly.
User Manual
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homexpert
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by Honeywell THR842DUK Wireless Digital Thermostat
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The THR842DUK is an easy-to-use thermostat designed to maintain a comfortable environment when you
are at home and reduce energy costs when you are away. One touch of the ECO button overrides the normal
temperature to maintain a lower, energy-saving level for a specified period of time (see page 11).
About your new wireless thermostat
Your new thermostat is pre-programmed and ready to go. Just check the steps below and change
settings if needed:
1Install and set up thermostat & relay box
(if this has not been done by a professional installer).......................................................... See pages 12-25
2Select heating (default) or cooling mode..................................................................................... See page 9
3Set desired indoor temperature................................................................................................ See page 10
QUICK START GUIDE 25.0
°c
Quick reference
Cooling system is
running (see page 9)
ECO mode countdown
(see page 11)
Heating system is
running (see page 9)
Current temperature
(or target temperature
when flashing)
ECO mode is on
(see page 11)
Indicates display
is showing target
temperature
Press to change
temperature
(see page 10)
Press to turn ECO mode
on or off (see page 11)
Press to turn thermostat
on or off (see page 8)
System fault
(see page 27)
Low battery warning
(see page 16 to replace
batteries)
Wireless signal
indicator (see
page 26)
Standby symbol appears
when thermostat is off
(see page 8)
eco
Operation
8
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by Honeywell THR842DUK Wireless Digital Thermostat
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On/off switch and frost protection
Press and hold the ON/OFF button as shown at left to turn the
thermostat on or off. When off, the thermostat will never activate the
cooling system, and will activate heating only if necessary to maintain
a minimum indoor temperature of 5º C (frost protection).
You can change the frost protection temperature to any level between
5º and 16º C, or turn this feature off so the heating system is never
activated when the thermostat is off (see page 23).
25.0
°c
5.0
°c
Press and hold
to turn on or off
Symbol appears when
thermostat is off
System maintains
minimum
temperature when
thermostat is off
Heating or cooling control
The thermostat is pre-set to control only your heating system. If
installed and set up correctly, it can also be used to control your
cooling system.
To switch between heating and cooling, press and hold the pand q
buttons together until the screen changes.
Press and hold both buttons for 5 seconds
NOTE: The thermostat will not switch to cooling control unless you
enable this feature (see page 23).
NOTE: When you change the system, the “Heating” and “Cooling”
symbols will appear for a few seconds, then disappear. Normally, these
symbols appear only when the heating or cooling system is running.
Heating changes to cooling
25.0
°c
25.0
°c
Operation
10
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by Honeywell THR842DUK Wireless Digital Thermostat
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Temperature control
When idle, the thermostat displays the current room temperature.
You can press the por qbuttons at any time to see the “target”
temperature the thermostat is trying to maintain.
One button press will display the target temperature, flashing. To
change it, press either button repeatedly, until the display shows
the temperature you want. After a few seconds the display will stop
flashing and change to show the current room temperature.
NOTE: You can use the ECO mode to temporarily override the target
temperature for a specified period of time (see page 11).
24.0
°c
25.0
°c
Current room temperature
Press buttons to display or change target
temperature
Energy-saving ECO mode
The ECO mode overrides thermostat settings to maintain a different
temperature for 1 to 24 hours. This can be useful to reduce heating or
cooling costs when you are away from home.
1Press the green ECO button to display timer.
2Press the por qbuttons to set timer (1-24 hours).
While in ECO mode, the screen will alternately display remaining time
and current room temperature. After the timer expires, the thermostat
will resume normal operation. Options:
• Pressthepor qbuttons to raise or lower the temporary ECO
temperature if needed.
• PresstheECO button again to cancel ECO mode and resume
normal operation.
Press to enter ECO mode
NOTE: The default ECO temperature is pre-set to 18º C. To raise or
lower the default temperature, see page 23.
1hr
3hr
eco
eco
18.0
°c
eco
Set number of hours
Change ECO temperature (if needed)
Installation and Setup
12
homexpert
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by Honeywell THR842DUK Wireless Digital Thermostat
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System installation
Heating/cooling systems
Relay box
Wireless
thermostat
Installation procedure
1Install relay box
2Connect system wiring
3Activate batteries and install
wireless thermostat
4Setup and test system operation
System
wiring
Install relay box
The relay box is wired directly to your heating
or cooling equipment. The thermostat
communicates with the relay box using a
wireless RF signal to control the system. Do not
install near metal objects or electronic devices
(TV, sound system, PC, etc.).
1 Make sure electrical power is off.
2Use a screwdriver to release latch and
remove relay box cover.
3Mount relay wall bracket as shown at
left. Install at least 30 cm from any metal
objects such as metal wall boxes and metal
equipment enclosures.
4Connect system wiring as shown on pages
14-15, then replace relay box cover.
NOTE: If you are not experienced in equipment installation, we recommend that these
procedures be done by a professional installer.
DISCONNECT ELECTRIC POWER BEFORE INSTALLATION: Can cause electrical shock or
equipment damage.
30 metres max. distance
Installation and Setup
14
homexpert
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by Honeywell THR842DUK Wireless Digital Thermostat
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Connect system wiring
Connect wiring from your heating or cooling
equipment to the relay box as shown at left. See
wiring diagrams on page 15 for details.
1 Make sure electrical power is off.
2Strip insulation to expose about 6 mm of
bare wire.
3Use a screwdriver to loosen terminal screw,
insert wire into slot, then tighten screw.
4Replace relay box cover, then restore
electrical power.
1.5 - 2.5 mm2
6 mm max.
NOTE: All wiring must comply with IEE
regulations. Keep AC mains supply/load cables
separate from equipment wiring.
Wiring diagrams
Burner (direct control) Combi boiler
Zone valve Cooling device
N L L
Wiring terminals
A B C
Terminal screws
Installation and Setup
16
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by Honeywell THR842DUK Wireless Digital Thermostat
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Activate batteries and test thermostat
Grasp and pull to remove the thermostat cover. Discard the plastic
tab inside to activate the batteries, then test as shown below.
To test the thermostat:
1Restore electrical power to the relay box.
2Hold the thermostat 2-3 metres from the relay box.
3Press and hold the ON/OFF button to turn off the thermostat.
4Press and hold the pand qbuttons together until the screen
changes as shown at left.
5.0
°c
i0se
NOTE: This symbol will flash on the screen when battery
power is low. Remove cover and replace batteries with
two fresh AA alkaline batteries.
Test thermostat (continued from page 16)
5Press the qbutton once.
6Press and hold the qbutton until the screen displays TEST. If
the green light on the relay box does not flash, the units are not
“bound” together. See page 28 and follow the instructions to
re-establish wireless communication.
CO0e
EEse
Remove
tab
Relay
box
Installation and Setup
18
homexpert
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by Honeywell THR842DUK Wireless Digital Thermostat
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Install thermostat
The wireless thermostat can be mounted in the table stand,
or on a wall. For wall mounting, remove the thermostat cover
and use a screwdriver to separate the thermostat from the
wall bracket as shown at left. Install the wall bracket about
1.2 to 1.5 metres above the floor.
• Donotinstallnearsourcesofhotorcoldair(radiators,
windows, heating or cooling ducts).
• Installatleast30cmfrommetalobjects.
• Installatleast1metreawayfromotherelectronicdevices
(TV, sound system, PC, etc.).
Table stand
assembly
Thermostat
Wall
bracket
Test thermostat location (continued from page 17)
Test signal strength to find a suitable location for the thermostat
before installation.
While still in Test mode (see pages 16-17), press and hold the q
button until the screen changes as shown, then move the thermostat
and check the screen display until you find a suitable location.
Signal strength:
0 — 2: No. Move the thermostat to another location.
3 — 5: Yes. Location is good.
Press and hold the ON/OFF button to stop the test.
EEse
55 3
Check
wireless
signal
strength
Press
and hold
to stop
25.0
°c
Press
and hold
again
Installation and Setup
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homexpert
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by Honeywell THR842DUK Wireless Digital Thermostat
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System test
After installation, you should check to make sure the system is
working properly.
1Check the power supply to make sure the system is on and the
green light on the relay box is off.
2Press the pbutton to raise target temperature to maximum
(35°C).
If the system is set up properly, the “heating” symbol should
appear on the thermostat display, the heating system should
begin running, and the green light on the relay box should be on.
3To stop the test, press the qbutton to lower the target
temperature to an appropriate level. The heating system should
turn off and the “heating” symbol on the thermostat screen should
disappear.
Set temperature to maximum
Installer setup
Installer settings allow you to customise how your system
works. Check the tables on pages 22-24 to see if any settings
need to be changed.
To change installer settings:
1Press and hold the ON/OFF button for 5 seconds.
2Press and hold the pand qbuttons together until the
screen changes.
3Press the por qbuttons to scroll through functions
quickly until you find one you want to change (see list on
pages 22-23).
4To change any setting, press the ON/OFF button, then
press the por qbuttons until the correct value is flashing.
5Press OFF again to save your choice, then use the por q
buttons to select another function.
To exit installer setup, press and hold the ON/OFF button
for 5 seconds.
35.0
°c
35.0
°c
Heat should turn on
25.0
°c
i0se
0e: 1
Press and hold both buttons for 5 seconds
Function Setting
Installation and Setup
22
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by Honeywell THR842DUK Wireless Digital Thermostat
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Installer setup functions
Function Description Setting Options
1: Ot Minimum boiler on/off time 1 minute **
Options: 1 to 5 minutes
See page 24 for important information
2: Cr Cycles per hour (CPH) 6 cycles per hour **
Options: 3, 6, 9 or 12
See page 24 for important information
3: Pb Proportional band width 1.5°C **
Options: 1.5° to 3°C
4: tO Temperature offset 0: No offset **
Options: +3° to -3°C
5: uL Maximum temperature allowed 35°C **
Options: 21° to 35°C
6: LL Minimum temperature allowed 5°C **
Options: 5° to 21°C
** Factory default setting
Installer setup functions
Function Description Setting Options
7: ES ECO default temperature 18°C **
Options: 5° to 35°C
8: HC Heating/Cooling options 0: No central cooling system installed **
1: Allows switching between heating and cooling systems
Thermostat cannot control cooling unless you select 1
9: OS Frost protection temperature 5°C **
Options: — (none) or 5° to 16°C
10: LC Loss of communications
instruction
0: Switch relay off **
1: Operate relay 20% on / 80% off
11: FS RESET TO FACTORY DEFAULT 0: No change
1: Select 1 to restore default settings. All customised
settings will be lost.
Enter Installer Setup (see page 19), then press por qfor access to system settings
NOTE: See descriptions of functions on page 23.
NOTE: See descriptions of functions on page 23.
Installation and Setup
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by Honeywell THR842DUK Wireless Digital Thermostat
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Description of functionsCustomised settings for your system
Your heating system Changes required Setting Options
Standard gas boiler
(<30kW)
None No change
Zone Valve None No change
Oil boiler Function 1: Ot
Function 2: Cr
Set to 4 minutes
Set to 3 CPH
Thermal actuator Function 2: Cr Set to 12 CPH
Electric heating Function 2: Cr Set to 12 CPH
Your cooling system Changes required Setting Options
Heat pump/air conditioner Function 1: Ot
Function 2: Cr
Function 8: HC
Set to 4 minutes
Set to 3 CPH
Set to 1
Fan coil Function 8: HC Set to 1
NOTE: After changing the above settings to accommodate a cooling system, you can switch the thermostat to
control either heating or cooling (see page 10).
Ot Minimum boiler off time: Check proper setting
for your system (see page 24).
Cr Cycles per hour: Check proper setting for your
system (see page 24).
Pb Proportional band width: If your heating system
is oversized for your home, you can compensate
by increasing the width of the control proportional
band up to 3°C.
tO Temperature offset: In some cases, the
thermostat must be installed in a location that
does not accurately control temperature for
optimum comfort in other rooms. You can set the
thermostat to compensate for this by adjusting
the offset.
uL Maximum temperature: When the pbutton
is pressed, the thermostat will not allow a target
temperature above the maximum you set.
LL Minimum temperature: When the qbutton is
pressed, the thermostat will not allow a target
temperature lower than the minimum you set.
ES ECO default temperature: This is the default
target temperature when the thermostat is in ECO
mode (see page 11).
HCHeating/cooling options: When set to 1, the
thermostat can control both heating and cooling
systems (see page 9).
OS Frost protection temperature: Minimum
temperature allowed when the thermostat is off
(see page 8).
LC Loss of communications: Determines how the
system operates if wireless signal is lost between
thermostat and relay box.
Appendix
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homexpert
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by Honeywell THR842DUK Wireless Digital Thermostat
27
In case of difficulty
Thermostat screen
is blank
• MakesuretwofreshAAalkalinebatteriesareproperlyinstalled(see
page 16).
Heating or cooling
system does not
respond
• Checkthermostatbatteries(seeabove).
• Makesureheatingandcoolingsystemshavepower.Checkfusesand
circuit breakers and replace or reset as needed.
• Checkwiring(pages14-15)andsystemconguration(pages21-25).
• Ifredlightonrelayboxison,thethermostatandrelayboxmayhavelost
communication with each other. Check for metal objects or other devices
that may block or interfere with the wireless signal. Try the test procedures
described on pages 16-20.
• Ifaboveremediescannotresolvetheproblem,thethermostatmay
have to be moved. Try a location closer to the relay box, or farther
away from interference by metal objects or electronic devices such as
televisions, sound systems, PCs, etc.
In case of difficulty
Desired temperature
cannot be maintained
• Ifremediesdescribedonpage26cannotresolvetheproblem,the
thermostat may have to be moved. Make sure it is not installed near
sources of hot or cold air (radiators, windows, heating or cooling
ducts).
If this symbol flashes on the screen during normal operation, a fault has
occurred.
• Pressthebuttonontherelayboxtoilluminatethegreenlightand
temporarily restore system function. This is a manual override which will
not correct the fault; it will only allow the system to provide heat until
the fault is corrected.
• Iftheproblemcannotbecorrected,contactHoneywellCustomerCare
for assistance (see back cover for contact information).
Appendix
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by Honeywell THR842DUK Wireless Digital Thermostat
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Re-binding procedure
If you must replace a wireless thermostat or relay box, the system
will not work until both devices can communicate with each other.
This is called binding. Follow the steps below to re-establish wireless
communication.
1Hold thermostat about 1 or 2 metres from the relay box, then
press and hold the relay button for 15 seconds.
Note: After 5 seconds the red light flashing pattern will change,
but you must hold down the button for at least 15 seconds to
clear previous binding information from memory.
2Release the relay button, then press and hold it again for 5
seconds, until the red light flashes evenly (“binding” mode).
3Release the relay button, then press and hold the thermostat
ON/OFF button to turn off the thermostat.
4Press and hold the thermostat pand qbuttons until the screen
changes as shown at left.
Press and hold relay box button
5Press the pbutton repeatedly until the display shows “CLr.”
Then press the ON/OFF button to clear previous binding to other
devices.
6Press the pbutton again to return to binding mode.
7Press the ON/OFF button again to re-establish wireless
communication with relay box. If successful, the red light on the
relay box will turn off, and the thermostat will return to normal
operation in Off mode a few seconds later.
CL
C0nt
5.0
°c
i0se
Press
and hold
Press
and hold
Re-binding procedure (continued from page 28)
25.0
°c
Red light
should turn off
Appendix
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by Honeywell THR842DUK Wireless Digital Thermostat
31
Limited Warranty
Honeywell warrants this product for 1 year from date of purchase. We undertake to replace or
repair at our discretion, products should they become defective within 1 year solely as a result
of faulty materials and or workmanship.
Understandably if the product has not been installed or maintained in accordance with
Honeywell’s instructions, has not been used appropriately or if any attempt has been made to
rectify, dismantle or alter the product in any way the warranty will be invalidated.
This product warranty states Honeywell’s entire liability. It does not extend to cover
consequential loss or damage or installation costs arising from a defective product.
If the product is defective, please return it together with a proof of purchase or receipt to the
place of purchase.
This does not affect your statutory rights.
If you require further information about this product, call the homexpert
tm
by Honeywell
technical helpline on 0845 604 2893.
For a full list of terms and conditions please visit www.homexpertbyhonyewell.com.
© 2010 Honeywell International Inc.
Declarations, disposal and recycling
Declaration
Honeywell hereby declares that this wireless product is in compliance with the essential
requirements and other relevant provisions of the Radio and Telecommunications Terminal
Equipment (R&TTE) directive, 1999/5/EC.
Disposal and recycling
Batteries and waste electrical products should not be disposed of with household waste.
Please recycle where these facilities exist. Check with your local authority or retailer for
recycling advice.
Please retain these instructions for future reference.
Honeywell
The Arnold Centre
Paycocke Road
Basildon, Essex
SS14 3EA
Technical Help Desk: 0845 604 2893 50051983-001 Rev. A
www.homexpertbyhoneywell.com © 2010 Honeywell International Inc
Need Help?
For assistance with this product please visit www.homexpertbyhoneywell.com, or call
Honeywell Customer Care at 0845 604 2893.
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