Horstmann HRT4-ZW Operating instructions

The HRT4-ZW is a wireless electronic battery powered room thermostat that uses
interoperable two-way RF mesh networking technology to provide optimum
comfort with close control of the energy used to heat the home without the need
for additional wiring or unsightly cable runs.
The HRT4-ZW will only operate when 2 x AAA batteries have been fitted and the
thermostat is installed and communicating with the ASR-ZW receiver unit.
INSTALLATION AND CONNECTION OF THE HRT4-ZW SHOULD ONLY BE CARRIED OUT
BY A SUITABLY QUALIFIED PERSON.
1
Wireless Z–Wave Battery Operated Electronic Room Thermostat with
TPI temperature control software and ASR-ZW receiver unit
HRT4-ZW and ASR-ZW
User and Installation Instructions

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.
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.
2
What is a room thermostat? ... an explanation for householders
For the user

The aerial symbol complete with radio wave symbols in the display of the HRT4–ZW
thermostat indicates that it is communicating satisfactorily with the ASR-ZW receiver.
A flashing radio wave indicates a loss of communication. This may be temporary and
can often be restored by turning the thermostat dial and increasing or decreasing the
temperature to make the thermostat switch. If this has no effect please see Z-Wave
pairing instructions on page 10.
A radio mast symbol with no radio waves indicates that the HRT4-ZW has not been
signed on to enable it to communicate with the ASR-ZW receiver. In this case you
may wish to contact the Installer as the indication is that the product has not been
commissioned when the installation took place. Alternatively see the Z-Wave pairing
instructions on page 10.
Further information on how the thermostat operates is contained in the ‘Explanation
for householders’ that precedes this section.
The display will show the
required temperature setting
and can be adjusted in
increments of 1°C.
To adjust the required
temperature setting turn the
dial anti clockwise to decrease
it and clockwise to increase it.
When the
thermostat is in
the ‘call for heat’
condition a flame symbol
will appear in the display.
Pressing the temperature
setting dial will allow the
user to check the current
actual measured room
temperature which will be
displayed for approx 7 seconds
before returning to the set
temperature.
The Horstmann HRT4-ZW thermostat uses the latest control technology to provide extremely
accurate temperature control which will help to keep your energy usage as low as possible without
affecting your comfort levels. In fact comfort levels may well be improved as the control accuracy
should ensure that the room does not ‘overheat’ before switching off.
User Instructions
3

4
Battery replacement
The HRT4-ZW runs on 2 x type AAA (Alkaline) non rechargeable batteries and is designed to give
a battery life of approximately two years.
When the batteries are nearing the end of their life a low
battery symbol will appear in the display and the batteries
should be changed within a few days. If the batteries are
not changed at this point eventually a ‘LO’ battery message
flashes intermittently in the display and if this happens the
batteries should be changed immediately.
To change the batteries it is necessary to remove the
thermostat from the wall. To do this first undo the two
captive screws at the base of the thermostat and swing the
thermostat up and away from the wall plate.
Remove the old batteries and replace them with two new AAA size
alkaline batteries ensuring that they are fitted correctly as indicated by
the terminal markings in the battery compartments.
Once the batteries are fitted, re-fit the thermostat to the wall plate
by engaging with the lugs at the top of the wall plate and push the
thermostat into position. Locate it over the captive screws at the base
of the wall plate and tighten so that the thermostat is locked into
position.
Check the temperature setting is correct and adjust if necessary.
Please dispose of the batteries responsibly.
ASR–ZW receiver unit
The ASR–ZW receiver unit receives the Z-Wave radio
signals from the HRT4–ZW room thermostat.
In the unlikely event of a communication failure it is
possible to override the system and switch On and Off
using the On/Off buttons on the ASR-ZW receiver as a
local override.
If the override is used to override the HRT4-ZW
thermostat when it is functioning correctly then the
override will be cancelled by the next switching operation
of the thermostat and normal operation will be resumed.
In any case, with no further intervention, normal
operation will be restored within one hour of the override
being operated.
Low battery symbol
appears rst when the
batteries are nearing
the end of their life
Batteries should be
changed immediately

5
Installing the ASR-ZW Receiver
The ASR-ZW receiver should be located as near as is practical to
the boiler or zone valve to be controlled, as well as a convenient
mains electricity supply. To remove the wall plate from the ASR-ZW,
undo the two retaining screws located on the underside, the wall
plate should now be easily removed. Once the wall plate has been
removed from the packaging please ensure the ASR-ZW is re-sealed
to prevent damage from dust, debris etc.
The wall plate should be fitted with the retaining screws located at
the bottom and in a position which allows a total clearance of at
least 50mm around the ASR-ZW receiver.
Direct Wall Mounting
Offer the plate to the wall in the position where the ASR-ZW is to be mounted and mark the fixing
positions through the slots in the wall plate. Drill and plug the wall, then secure the plate into
position. The slots in the wall plate will compensate for any misalignment of the fixings.
Wall Box Mounting
The wall plate may be fitted directly on to a single gang flush wiring box complying with BS4662,
using two M3.5 screws. The receiver is suitable for mounting on a flat surface only; it is not suitable
for mounting on an unearthed metal surface.
Installation Instructions

6
Electrical Connections
WARNING: ISOLATE THE MAINS SUPPLY BEFORE COMMENCING INSTALLATION
As the HRT4-ZW is a wireless product with no electrical connections all electrical wiring will be
made to the ASR-ZW receiver.
All necessary electrical connections should now be made. Flush wiring can enter from the rear
through the aperture in the backplate.
The mains supply terminals are intended to be connected to the supply by means of fixed wiring.
The receiver is mains powered and requires a 3 Amp fused spur.
The recommended cable size is 1.Omm2.
The receiver is double insulated and does not require an earth connection, an earth connection
block is provided on the backplate for terminating any cable earth conductors. Earth continuity must
be maintained and all bare earth conductors must be sleeved. Ensure that no conductors are left
protruding outside the central space enclosed by the backplate.
Two example circuit diagrams for typical boiler installations are shown opposite. These diagrams are
schematic and should be used for guidance only.
Please ensure that all installations comply with the current IEE regulations and the boiler
manufacturer’s installation instructions.
For reasons of space and clarity not every connection has been included and the diagrams have
been simplified, for instance some earth connections have been omitted.
N L 1 2 3 4
230V 50V COMM OFF ON
Internal
Electronics
ASR-ZW Receiver internal wiring diagram
The receiver has Voltage Free contacts. A link between
Live and terminal 2 is required for mains Voltage
applications.

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Zone/Heating control basic layout
This diagram shows a receiver used in a
conventional fully pumped system using a 2
port spring return zone valve with auxiliary
switch to control the pump and boiler. Please
note: hot water control will need to be
controlled by the use of a programmer or
time switch.
Mains supplies to both
the receiver and the
boiler are omitted for
clarity. Please consult
the boiler manufacturers
installation handbook
before commencing any
installation work.
N L 1 2 3
230V
230V
50V
50V
OFF
N = Neutral
L = Live
S = Boiler switch output
R = Boiler switch return
Boiler external control
connections shown
ONCOMM
N L S R
4
Internal
Electronics
N L 1 2 3
230V
230V
50V
50V
OFF ONCOMM
4
Switch live from
programmer or mains
feed from wiring
centre (fused 3 Amp)
2 Port spring return
motorised valve with
auxiliary end switch
To Pump
and Boiler
N
L
Internal
Electronics
Typical combi boiler system
with built in timer
This diagram shows a typical receiver and
combination boiler installation, where
the external boiler control is connected
via switching terminals (a link may have
to be removed on the boiler switching
control terminals). Mains supplies to both
the receiver and the boiler are omitted
for clarity. Please consult the boiler
manufacturers installation handbook
before commencing any installation work.

8
Fitting the HRT4-ZW Room Thermostat
Before final installation it is advisable to commission the product and ensure that the Thermostat
and Receiver are communicating satisfactorily. First install the 2 x type AAA batteries provided
making sure that they are fitted correctly as indicated by the markings in the battery compartment.
Once the thermostat and receiver are successfully ‘paired’ the thermostat can be installed in its
correct location. Please see Z-Wave pairing instructions on page 10.
Avoid installing the thermostat against or behind any large metal surfaces which could interfere
with the radio signals to and from the ASR-ZW receiver. The HRT4-ZW should be mounted on an
internal wall approximately 1.5 metres from floor level using the wall plate provided and should be
in a position away from draughts, direct heat and sunlight. Ensure that there will be enough space
to allow easy access to the two retaining screws located at
the base of the wall plate.
Before fixing the wall plate in position check to see that
the thermostat and Receiver are still able to communicate
satisfactorily by turning the thermostat temperature up and
down to switch the ASR–ZW receiver on and off.
Offer the plate to the wall in the position where the ASR-ZW
is to be mounted and mark the fixing positions through the
slots in the wall plate. Drill and plug the wall, then
secure the plate into position. The slots in the wall
plate will compensate for any misalignment of the
fixings.
Complete the installation by swinging the room
thermostat into position by engaging with the lugs at
the top of the wall plate before pushing it carefully
home into its plug-in terminal block.
Tighten the 2 captive screws on the underside of the
unit.
Now ensure that the heating system is responding to
the ON/OFF commands from the Room Thermostat
and explain its operation to the householder before
handing over these User Instructions

9
DIL switch settings – TPI temperature control software
Thermostats using TPI (Time Proportional Integral) control algorithms will reduce the temperature
swing that normally occurs when using traditional bellows or thermally operated thermostats.
As a consequence, a TPI regulating thermostat will maintain the comfort level far more efficiently
than any traditional thermostat.
When used with a condensing boiler, the TPI thermostat will help to save energy as the control
algorithm allows the boiler to operate in condensing mode more
consistently compared to older types of thermostat.
• DIL switch numbers 7 and 8 should be set as diagram opposite.
• For Gas boilers set the TPI setting to 6 cycles per hour.
(Default setting)
• For Oil boilers set the TPI setting to 3 cycles per hour.
• For Electric heating set the TPI setting to 12 cycles per hour.
Switch positions for
different TPI settings.

lnstructions for pairing the HRT4-ZW room thermostat with
the ASR-ZW receiver
The HRT4-ZW uses the latest Z-Wave wireless communication technology to give a reliable wireless
link that should not suffer from interference from other nearby devices. The device comprises of a
thermostat (the HRT4-ZW) and its receiver unit (the ASR-ZW). Pairing the devices on site ensures
reliable communication.
Follow these steps to ensure that the HRT4-ZW thermostat will communicate satisfactorily
with it’s receiver, this is best carried out with the HRT4-ZW Thermostat held nearby the
(powered) ASR-ZW receiver.
Stage 1
1) Set the number 1 DIL switch on the back of the HRT4-ZW thermostat
to the On (Up) position and the display on the HRT4-ZW will change
to show the letter ‘I’. If the letter ‘L’ appears, carry out stage 1A opposite.
2) Power up the ASR-ZW receiver unit
3) The network LED on the ASR-ZW receiver should be flashing.
4) Press the dial on the front of the HRT4-ZW thermostat once
so that the ‘I’ in the display flashes.
5) Press and hold the network button on the ASR-ZW receiver
until the On indicator flashes (green) before the Off indicator
becomes solid red.
6) After a few seconds the radio mast symbol
will appear in the display along with the letters IP.
7) Reset the number 1 DIL switch on the back of the HRT4-ZW
to the Off position and the temperature should return in the display.
8) Now check the receiver responds to the thermostat on and off
commands by increasing and decreasing the temperature settings until it switches accordingly.
N.B. There is a half second delay in switching On and Off on receipt of the command.
9) The Z-Wave communication link is now successfully established.
10
Network LED Network
button

Under normal circumstances the HRT4-ZW thermostat and ASR-ZW receiver will be ‘paired’
easily by following the procedure shown under Stage 1 of the pairing instructions.
Only use Stage 2 if a radio link cannot be successfully established between the two
devices.
Stage 1A – Only used if ‘L’ is displayed instead of ‘I’
1) Turn the dial of the HRT4-ZW until the letter P appears in the display.
2) Press the dial twice.
3) A second P should appear in the display which now shows `PP’.
4) Turn the dial until the letter ‘I’ appears in the display and return to the main instruction.
Stage 2 – Only used if the above procedure does not establish
a successful communication link
1) Turn the dial until the letter P appears in the display.
2) Press the dial twice and PP should appear in the display.
3) Now turn the dial until letter E appears in the display.
4) Press the dial once and the display should flash.
5) Press and hold the network button on the ASR-ZW receiver until it starts to flash.
6) Turn the dial until the letter `I’ appears in the display and return to the main instruction.
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Thermostat specifications HRT4-ZW
Power supply 2 x AAA alkaline batteries
Temperature accuracy +/- 0.5°C
Transmitter frequency 868MHz
Dimensions 86mm x 86mm x36.25mm
Pollution control Degree2
Design standard EN60730 - 2-9
Temperature range 5°C – 30°C
Rated Impulse voltage Cat 1 – 1500v
Enclosure protection IP30
Operating temperature range 0-40°C
Double Insulated
Case material Thermoplastic, flame retardant
Receiver specification ASR-ZW
Power Supply 230V AC 50Hz
Contact type Micro disconnection
Voltage free
Contact rating 3 (1) Amps 230v AC
Operating temperature range 0-40°C
Double Insulated
Rated Impulse voltage Cat 1 – 1500v
Pollution control Degree2
Enclosure protection IP30
Case material Thermoplastic, flame retardant
Dimensions 86mm x 86mm x 36.25mm
Horstmann Controls
South Bristol Business Park, Roman Farm Road, Bristol BS4 1UP
E-mail: [email protected]o.uk
Web site: www.horstmann.co.uk
Leaflet number P83852 – Issue 1