Honeywell DT92 User Manual

FEATURES

DT92

WIRELESS DIGITAL ROOM THERMOSTAT

PRODUCT SPECIFICATION SHEET

The new DT92 family of wireless digital room
thermostats is a range of market leading products
designed to provide comfort with economy in modern
heating systems.

Comprising a battery-powered room thermostat and a
mains switching relay box, DT92 features robust 2-way
RF communications between the units. This allows
signal strength testing to help the installation process.
The RF link between both units is already set (pre­bound) at the factory, so the product is ready for
immediate installation.

Energy efficiency is addressed by state-of-the-art TPI
control performance and an ECO button energy saving
feature. Applications include control of gas or oil-fired
boiler systems, underfloor heating, electric heating and
zoning systems.

With a modern fresh look that complements any style
of décor, and a range of valued features for users and
installers alike, DT92 sets the standard for simple
environmentally-friendly wireless room thermostats.

•

Energy saving TPI control performance

• Advanced self-learning control adapts to the

environment and ensures close temperature
control with minimum energy usage

• Slim modern styling

• Simple user interface with large high contrast

display and easy-to-read characters

• Display shows room temperature, with option to

inquire about setpoint

• 5°C to 35°C setpoint range with 0.5°C

increments, using ▲ and ▼buttons

• Off/standby button, allowing manual switch off,

with frost protection active

• Adjustable off/standby setpoint 5°C to 16°C or

DT92 can be set to off completely

• Room thermostat is battery powered by 2 x AA

(LR6) alkaline cells giving up to 4 years battery
life (minimum 2 years), with battery low warning

• Simple battery change by unclipping front cover

• Relay switching box is 230Vac mains powered

with 24…230Vac SPDT potential-free contacts

• 5 A resistive, 3 A inductive switch rating

• 2-way RF communications at 868MHz radio

frequency band, giving typical reliable range of
30m in houses

• Transmission and signal strength test features

to guarantee good room thermostat placement

• RF link between units is pre-set at the factory

• Installer Mode allows operation to be

customised for the application and the needs of
the user

• NVRAM storage of setup parameters, ensuring

these are never lost

• Setpoint limits can be programmed in

• Special ‘fail-safe’ mode, should RF

communications be temporarily lost

• Manual override possible at relay box

• Optional table stand supplied for thermostat

FEATURES UNIQUE TO DT92E ECO MODEL

• Energy saving ECO button allows user to

change to a lower, energy saving setpoint for a
timed period of their choosing (1…24 hours)

• Display shows countdown of time remaining in

ECO energy saving mode

EN0H 8580 UK07 R1 03/09

SPECIFICATIONS

Room thermostat

Power supply : 2 x 1.5V IEC LR6 (AA) Alkaline cells

Battery life : Minimum 2 years (with correctly specified

Battery low
warning

Battery
replacement

Relay Box

Power supply : 230 V, 50…60Hz 1VA max. Note –

Switch type : SPDT (single pole double throw )

Electrical rating : 24…230 V, 50…60 Hz, 5 A resistive, 3 A

Relay life : 100,000 operations minimum

Wiring : Terminal block for mains and relay wiring,

Wiring access : Rear and left side

ELECTRICAL

alkaline cells)

: Display indicates when battery power

reserve is low. Unit will continue to
function for a minimum of 4 weeks after
the first indication is given

: Configuration settings stored in NVRAM,

so are retained during battery
replacement

requires permanent mains power supply

potential free

inductive (0.6pf)

for wires up to 2.5mm²

RF SPECIFICATION

Operation band : ISM (868.0-868.6) MHz, 1% duty cycle

Communication
range
Communication
technology

Blocking
immunity

RF binding
method

RF test features : Transmission and signal strength tests to

: 30 m in a residential building environment

: 2-way RF, using short, high rate

transmissions to minimise air time and
avoid collisions

: Receiver class 2 (ETSI EN300 220-1

version 2.1.1)

: Units are pre-bound at the Factory. Field

re-binding can be done, if required

assist location of components

ENVIRONMENTAL & STANDARDS

Operating
temperature
Shipping &
storage
temperature
Humidity : Humidity range 10% to 90% rh, non-

IP class : IP30

Approvals : CE mark, complying with standards

: 0°C to 40°C

: -20°C to 55°C

condensing

EN60730-1 (2001), EN60730-2-9 (2002),
EN55014-1 (2006), EN55014-2 (1997),
ETSI EN300 220-3, ETSI EN301 489-3

: WEEE & RoHS compliant

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

TEMPERATURE CONTROL

Sensing element : 10K (@25°C ) NTC thermistor

Temperature
setting range

Control form : Self-learning TPI Fuzzy Logic algorithm

Proportional
band

Minimum on/off
time

Cycle rate : Adjustable to suit the application 3, 6, 9,

Temperature
control accuracy

Frost protection : 5°C when thermostat switched to

Positive off : Positive off possible (no frost protection)

ECO energy
saving

Fail-safe
operation

Relay box
manual override

: 5°C to 35°C setpoint range in 0.5°C

increments

: 1.5°C adjustable up to 3°C in 0.1°C

increments

: 1 minute, adjustable up to 5 min in 1 min

increments

12 cycles per hour

: ± 0.5°C (or better) at 20°C, 50% load and

3°C /hour temperature ramp

off/standby, adjustable 5°C to 16°C

: Frost protection not available in cooling

mode

by setting in Installer Mode

: Setpoint default 18°C, adjustable 5°C to

35°C

: If temperature measurement system fails,

unit will continue to operate on the
assumption of a 10% load

: If RF communication fails, relay box can

be set to switch off or operate at 20% on

: Pressing the button on the relay box will

temporarily override the current relay
position. The relay status may change
with the next communication from the
room thermostat

USER INDICATIONS

Information : Current room temperature, setpoint,

off/standby mode, relay box relay status
(flame), RF communication, ECO mode
active, ECO mode countdown.

Warnings : Frost protection, internal fault, battery

low, loss of RF communications.

: Lockout (operation not permitted) and

boiler fault are possible, depending on
application and configuration of other RF
products.

METRICS

Dimensions : 90 x 92 x 27mm (thermostat)

: 90 x 92 x 30.5 mm (relay box

: 157 x 115 x 105 mm (pack)

Weights : 154g (thermostat with batteries)

: 96g (relay box)

: 380g (pack)

2 EN0H 8580 UK07 R1 03/09

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

ORDERING SPECIFICATION

Model Description Literature

DT92A1004

DT92E1000

Wireless digital room thermostat
(System pack, comprising DT92A room thermostat + BDR91 Relay Box)
Wireless digital room thermostat with ECO energy saving feature
(System pack, comprising DT92E room thermostat + BDR91 Relay Box)

Multi-lingual

Multi-lingual

Note: the room thermostat and relay box in each system pack are pre-bound (linked together) at the factory. This
means they will recognize and communicate with each other as soon as they are powered up. The complete device
is therefore ready for immediate installation.

CONTROLS / DISPLAY LAYOUT

frost protect indicator heating demand indicator

temperature display

setpoint indicator

fault indicator

battery low warning

Room Thermostat

DT92A

RF co mmunications

indicator

off/standby indicator

Relay B ox

BDR91

Room Thermostat

DT92E

ECO countdown indicatorECO mode active

setpoint chan ge buttons

ECO button

off/standby button

ECO mode co untdown timer

gree n LED, indicates

• rela y on/off status

• transmission test

pus h button

red LED, indicates

• status in binding or reset modes

• loss of RF comm unicatio ns

3 EN0H 8580 UK07 R1 03/09

MAIN FEATURES

Extra-Large Display

The DT92 has a large display, ensuring it is easy to
read and allowing essential information to be displayed,
when required. The large characters and high contrast
screen are especially important for those with impaired
vision.

Simple Interface

The user interface has been made as simple as
possible to make DT92 very easy to use. Buttons have
been labeled ▲ and ▼ to identify them as the means
of increasing and decreasing (respectively) the setpoint
temperature. The display normally shows the actual
room temperature. When one of the buttons is first
pressed, the setpoint temperature is shown flashing,
accompanied by the ▲ and ▼ symbols. Further
buttons presses will increase or decrease the setpoint
in increments of 0.5°C.

Off/Standby Button, with Frost Protection

The off/standby button allows DT92 to switch off the
heating (or cooling) system at the touch of a button. To
prevent accidental switch-off, the button must be held
for 2 seconds to activate the change. When off, DT92
will maintain control at a frost protection setpoint,
factory set to 5°C but adjustable between 5 and 16°C.
If required, frost protection can be switched off, to
provide a positive off function. These adjustments are

made by entering the DT92 Installer Mode.

Installer Mode

The Installer Mode is where DT92 can be configured
for different applications, and customized to meet the
needs of the user. The operating properties that can be
adjusted are called parameters, and these are
described in detail on page 6.
Parameters are as follows:

• Minimum on/off time

• Cycle rate

• Proportional band width

• Temperature measurement offset

• Upper setpoint limit

• Lower setpoint limit

• Energy saving ECO temperature (on DT92E only)

• Selection of heat/cool changeover operation

• Off/Standby setpoint

• Room temperature sensor use (when used with

HR80 intelligent radiator valves

• Failsafe operation mode (if RF comms are lost)

• HR80 window open function enabling

• HR80 local override function enabling

• Reset all parameters to factory settings

Installer Mode is entered via a sequence of button
presses. The buttons are also used to scroll between
parameters and to make changes to their values.

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

2-Way RF Communications

RF communications between the room thermostat and
the relay box is 2-way, making it more efficient and
reliable, and allowing the room thermostat to display
information from the relay box, such as actual relay
status or communications loss.

Signal Strength Test Mode

Another benefit of 2-way RF is to allow the room
thermostat to display the strength of the signal that the
relay box is receiving. This ensures the thermostat can
be positioned in the best possible location for system
performance.

Reliable RF Communications in 868MHz band

868MHz is a well regulated band where continuously
transmitting devices are not permitted. Together with a
1% transmission duty cycle, this means the possibility
of interference or clashing messages is minimized, and
increases the reliability of communications.

NVRAM Storage of Settings

All parameter settings are stored in a special kind of
memory called NVRAM so they will be retained
indefinitely even if the batteries are removed.

Advanced Self-learning TPI Control

DT92 uses a self-learning ‘fuzzy logic’ time-proportional
control algorithm. This form of control is better than
conventional PI control as it has a faster response and
better performance in steady state conditions. It
performs equally well in a wide range of different
installations, and ensures energy savings by controlling
closer to setpoint and minimising temperature
overshoots.

Additional Energy saving ECO feature

In a heating system, one of the best ways to save
energy is to reduce the setpoint temperature. The DT92
green ECO button provides a simple and convenient
way of doing this for a period of time of the user’s
choice. The ECO energy saving setpoint is pre-defined
in the Installer Mode. The factory setting is 18°C, but it
can be adjusted (between 5°C and 35°C) to give a
timed boost, if required. When the ECO button is
pressed, the user is given the chance to set the time
required at this new temperature, from 1 hour to 24
hours in 1 hour increments. The display indicates that
ECO mode has been set, and will count down the time
remaining in energy saving mode. Should they wish to
readjust the temperature setting, they can do that too,
using the ▲ and ▼ buttons.

ECO mode is cancelled simply by pressing the ECO
button again.

4

INSTALLATION

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

Installation Process

To ensure best system performance, there is an
optimum sequence of installation operations and test
steps. These are as follows:

1. Install BDR91 relay box, connect to mains, and
power up.

2. Before mounting DT92 thermostat onto backplate,
power it up (activate batteries).

3. Bring DT92 thermostat to a distance 2-3 m from
relay box and initiate RF Communication Test.
This confirms that relay box is wired correctly and
that both devices are bound (linked) to each other.
If this test does not work, the 2 units must be reset
and bound to each other by following the procedure
for Binding / Re-binding.

4. Take the DT92 thermostat to the proposed
mounting location, and initiate the Signal Strength
Test. This will indicate if the thermostat is suitably
positioned to provide a reliable signal for the relay
box. If the signal strength is too low, the thermostat
must be repositioned.

5. When a suitable position is established, the
backplate can be mounted on the wall and the
thermostat can be attached to it.

.

Installing the BDR91 Relay Box

For best performance, the BDR91 Relay Box should be
installed in an open space, at least 30cm distance from
any metal objects including wall boxes and boiler
housing. It should not be mounted on a metal wall box.

Location

a.

5

b.

WIRING CONNECTIONS

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

a.

c.

a. Boiler
b. Boiler (potential free connection)
c. Zone valve
d. Air conditioner

b.

d.

Note: BDR91 Relay Box requires a permanent mains power supply.

Completing the BDR91 Relay Box Installation

6

Installing the DT92 Room Thermostat

Before mounting the DT92 thermostat onto its
backplate, power it up by removing the battery tab.

Bring the DT92 thermostat to a distance 2-3 m from
relay box and initiate the RF Communication Test to
confirm the BDR91 relay box is wired correctly and that
both devices are bound (linked) to each other.

2 – 3 m

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

RF COMMUNICATION TEST

Initiate RF Communication Test by the following
sequence of actions applied to the DT92 thermostat.

If green LED does not
flash, units are not linked
and must be bound
together again.

7

If green LED flashes every 6
seconds, units are correctly
bound and a suitable location
for the DT92 thermostat can
now be identified.

Locating the DT92 Room Thermostat

For best performance, install in an open space where
DT92 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. Leave
at least 30cm distance from any metal objects and at
least 1 metre from any other electrical equipment.
Do NOT position the thermostat near sources of heat
(radiators, hot air vents, TV or lights), near doors or
window, or in direct sunlight.

Select the preferred location and test the Signal
Strength before installation.

SIGNAL STRENGTH TEST

The Signal Strength Test is used to find a suitable
position for the DT92 thermostat, such that the signal
received by the BDR91 relay box is high strength. This
will optimize system performance.
The BDR91 relay box measures the strength of the
signal received from the room thermostat, and upon
request, sends this measurement back to the room
thermostat using the 2-way RF communication link.
This is expressed as a number between 0 and 5, where
5 is the highest strength. If this number is 2 or less, the
signal strength is too low, and room thermostat should
be repositioned. The DT92 room thermostat
continuously updates this measurement, every few
seconds.

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

Poor signal, reposition
thermostat until signal
strength > 2

Strong signal,
thermostat can now be
mounted in this location

8

Mounting the DT92 Room Thermostat

Wall mounting

Completing the installation

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

Optional table stand

TEST AND BINDING FLOWCHART

Press for 5 seconds to exit any mode

9

BINDING / RE-BINDING PROCEDURE

The RF link between the Room Thermostat (DT92) and
the Relay Box (BDR91) 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.

The sequence of operations required is:

1. Bring thermostat close to relay box (around 1m.)

2. Reset stored data in relay box

3. Put relay box into binding mode

4. Reset stored data in room thermostat

5. Put room thermostat into binding mode

6. Bind room thermostat to relay box

Reset Stored Data in Relay Box

Press and hold the push button for 15s to reset the
stored data in the BDR91 relay box.
The red LED will give a brief flash every second to
verify reset has happened.

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

Put Relay Box into Binding Mode

Press and hold the push button for 5s to put the BDR91
relay box into binding mode.
The red LED will flash 0.5 seconds on, 0.5 seconds off
to verify it is now in binding mode.

The BDR91 relay box will remain in binding mode for 3
minutes, before generating an error message if no valid
binding instruction has been received.
It must be put back into binding mode if further
attempts to bind are required.

10

Reset Stored Data in Room Thermostat

Follow the sequence of steps below to reset the stored
binding data in the room thermostat.

Put Room Thermostat into Binding Mode

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

Bind Room Thermostat to Relay Box

With both units in binding mode, pressing the
off/standby button on the room thermostat will bind
them together.
To verify it is now bound, the red light on the relay box
will immediately stop flashing. After about 5 seconds,
the room thermostat will come out of binding mode and
go back to off mode.

11

SYSTEM OPERATION

RF Signal Propagation

As the DT92 room thermostat and relay box
communicate using RF technology, special care must
be taken during installation. The location of the RF
components as well as the building structure may
influence performance of the RF system.
DT92 uses 2-way RF technology, and this allows the
signal strength to be measured and communicated, to
ensure correct placement of the room thermostat in a
high signal strength area. See RF Communication
Test and Signal Strength Test sections for a
description of these features.

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

Within a typical residential building 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 Relay Box 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.

Automatic Operation

The display on the DT92 room thermostat will indicate
(by means of the flame symbol) the actual status of the
relay in the BDR91 relay box.
The green LED on the BDR91 relay box will illuminate
when the relay is on, and will go off when the relay is
switched off.

12

Temporary Manual Override

Pressing the button on the BDR91 will temporarily
override the current relay operation. The green LED will
indicate the relay position.

Loss of RF Communications

If RF communications is lost, for whatever reason, the
BDR91 relay box will operate in failsafe mode (as set in
the Installer Mode) and the red LED will illuminate.
The DT92 room thermostat will flash the RF symbol
until communications are restored.

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

PRODUCT DIMENSIONS

90

27 90

30.5

92

13

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

INSTALLER MODE – APPLICATIONS SETTINGS

The DT92 has a special Installer Mode where some features can be adjusted to suit the application and the needs or
lifestyle of the user. Each adjustable feature is called a Parameter. These are described below.

Parameter Description and typical use

Minimum ON/OFF time DT92 is able to set a minimum limit for the on and off times of the controlled device or

appliance, to prevent damage or excessive wear. This minimum time can be set to 1,
2, 3, 4, or 5 minutes, and is particularly important for heating applications with oil
boilers, or air conditioning applications with compressors. Recommended settings are
shown in the next table.

Cycle rate Within the control proportional band, the output will be cycled several times per hour,

to give precise temperature control. This can be set to 3, 6, 9, or 12 cycles,
depending on the application. Recommended settings are shown in the next table.

Proportional band width The proportional band is the temperature band, adjacent to the set temperature point,

within which the thermostat will cycle the controlled output (to control the boiler, for
example). Above or below this band the output will either be fully on or fully off.
The band can be adjusted up to 3°C (default 1.5°C) to provide improved temperature
control. This is useful for (a) well-insulated homes with over-sized heating systems or

(b) air systems with a fast response
Temperature
measurement offset

If the thermostat is located in a particularly hot/cold location and cannot be moved,

then the measured/displayed temperature can be adjusted by +/- 3°C. This is useful if

the homeowner wants the reading to match the temperature display on another

appliance.
Upper / Lower
temperature limits

The normal upper temperature limit of 35°C can be reduced as low as 21°C to save

energy. The normal lower limit of 5°C can be raised as high as 21°C to protect

inhabitants from the cold.
Energy saving ECO
temperature

On the DT92E ECO model, pressing the ECO button immediately puts the thermostat

into energy saving mode, where it will control at this predefined temperature for as

long as the user wishes. This temperature can be set from 5°C to 35°C.
Heating or Cooling
operation

DT92 can be used for heating or cooling applications. If heating/cooling changeover is

selected, the thermostat can be manually switched from heating to cooling (and back

again) by pressing and holding the ▲ and ▼ buttons together for 3 seconds, in

normal operating mode.
Off/standby setpoint When the off/standby button is activated, the DT92 will control to a special off/standby

setpoint. By default this is set to 5°C to provide frost protection, but it can be set up to

16°C if required. It can also be set off, by setting the parameter value to -- to provide

a positive off function. In cooling mode the default setting is off.
Room temperature
sensor use

In normal operation the DT92 uses it own temperature sensor. If it is operating in a

wireless system with HR80 programmable radiator valves the DT92 needs to know

that it is controlling HR80s. In addition, there is a choice of whether the HR80s can

use their own in-built temperature sensors, or whether they will use the temperature

sensed by DT92. The 3 choices then become:

a) DT92 operating without HR80

b) DT92 operating with HR80, HR80 using their own temperature sensor

c) DT92 operating with HR80, HR80 using the temperature sensed by DT92
Failsafe operation mode Should RF communications be interrupted for a significant period of time, for

whatever reason, it is possible to specify the desired mode of operation under these

circumstances. The choices are for the Relay box to switch off, or for it to operate at

20% on.
HR80 window open
function enabling

In a system where DT92 is operating with HR80 programmable radiator valves, the

HR80 is capable of detecting whether a window has been opened. This parameter

enables the HR80 response to this condition – it can either shutdown (enabled) or

operate as before (disabled)
HR80 local override
function enabling

In a system where DT92 is operating with HR80 programmable radiator valves, the

user can override the room temperature setpoint using the HR80. This parameter can

allow (enable) this operation, or prevent it (disable).
Reset parameters This provides a means of resetting all the parameters to the factory supplied values.

14

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

Some parameters require to be set to match specific applications. Recommended settings are shown in the table

Specific Applications Setting What requires to be changed?

Cycle

s/

Minimum

on/off time

hour

Heating

Gas boilers
(<30kW)
Oil boiler 3 4 1. Set minimum ON/OFF time to 4 minutes

6 1 No changes required

2. Set cycle rate to 3 cycles/hour
Thermal actuator 12 1 Set cycle rate to 12 cycles/hour
Zone valve 6 1 No changes required

Air
conditionin
g

1. Configure the thermostat to allow switching between

heating and cooling modes (set parameter HC = 1)

2. Set the thermostat to the required mode of operation

(heating or cooling) by pressing the ▲ and ▼
buttons together for 3 seconds when in normal run

mode (does not work in off/standby mode).
Heatpump / Air
conditioner

3 4 1. Set minimum ON/OFF time to 4 minutes

2. Set cycle rate to 3 cycles/hour

Fan-coil unit 6 1 No changes required

INSTALLER MODE – HOW TO SET PARAMETERS

Each parameter is identified by a 2-letter code, and has a range of values. These are shown in the table below,
followed by instructions on how to enter Installer Mode, how to select a parameter and change its value, and finally

Description Parameter Range of values Factory (default) value

Minimum ON/OFF time Ot 1, 2, 3, 4, 5 minutes 1 minute
Cycle rate Cr 3, 6, 9, 12 cycles/hour 6
Proportional band width Pb 1.5 to 3.0°C 1.5°C
Temperature measurement offset tO -3 to 3°C 0
Upper setpoint limit uL 21 to 35°C 35°C
Lower setpoint limit LL 5 to 21°C 5°C
Energy saving ECO temperature
(this parameter is only available on
the DT92E model)
Selection of heat/cool changeover HC 0 = disable

* Off/standby setpoint OS -- = off,

** Room temperature sensor use Su 0 = DT92 alone

Failsafe mode (loss of RF
communications)
** Enable HR80 window-open
function
** Enable HR80 local override HL 0 = disable

Reset parameters FS 0, 1 1 (factory settings)
* In cooling mode the off/standby setpoint defaults to OFF
** Only required if system contains HR80 programmable radiator valves

ES 5 to 35°C 18°C

0

1 = enable

5°C

5 to 16°C

0

1 = DT92 with HR80, using

HR80 sensors

2 = DT92 with HR80, using

DT92 sensor

LC 0 = switch OFF

0

1 = operate at 20% ON

H0 0 = disable

0

1 = enable

1

1 = enable

15

To enter Installer Mode:

a. Put DT92 into off/standby mode by pressing and

holding the off/standby button for 2 seconds.

b. Now press and hold both ▲ and ▼ temperature

adjustment buttons for 3 seconds, until the
display shows the word “Inst”.

c. Press the ▲ button to get to the first parameter

Ot. The parameter code is shown on the display
separated by a colon from the parameter value.

Parameter

Value

To select and change a parameter:

d. Use the ▲ and ▼ buttons to move from one

parameter to another.

e. Press the off/standby button to select the

parameter value, ready to change

f. Use the ▲ and ▼ buttons to adjust the

parameter value. When the correct value is
flashing, confirm the selection by pressing the
off/standby button again, returning to the
parameter menu.

To exit Installer Mode:

g. Press and hold the off/standby button for 3

seconds
Note: Installer Mode will exit automatically after 10
minutes if no buttons are pressed.

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

INSTALLER MODE - FLOWCHART

Only available

on DT92E model

ES parameter

16

DT92 WIRELESS DIGITAL ROOM THERMOSTAT

ENERGY EFFICIENCY AND THE ENVIRONMENT

Home energy use is currently responsible for more than ¼ of the total carbon emissions which contribute to climate
change. Heating and hot water systems based on boilers account for 2/3 of this figure, so it is important to
understand how controls can help to maximize energy efficiency while maintaining comfort.
DT92 temperature controls should be used in conjunction with appropriate time controls.
In order to save energy the following general points should be observed:

1. Ensure the system contains a room temperature thermostat and a hot water temperature thermostat (except for
Combi boiler systems), and that both are set to appropriate temperature levels.

2. Programme the heating and hot water to be off when the house is not occupied. If possible frost damage to any
exposed pipework is a concern, it is advisable to fit a frost protection thermostat or system. Honeywell can advise
on this.

3. It is normal to have the heating system switched off, or set-back at night when heating is not required.

4. Think about how domestic hot water is used. In a storage system, it is not necessary to have this switched on all

the time, even when the house is occupied.

5. Do not programme excessive heatup times for the central heating. If the occupier is out of the house, or still in
bed, much of this heating would be unnecessary.

6. In the evening, when the house is up to temperature, it is often possible to switch the heating off up to an hour
before going to bed, without any noticeable reduction in comfort.

The DT92 product family 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 in the UK, 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.

Honeywell Control Systems Ltd.

Newhouse Industrial Estate,
Motherwell ML1 5SB,
United Kingdom

http://europe.hbc.honeywell.com

EN0H 8580 UK07 R1 03/09