Secure HRT4-B Operating instructions

User and Installation Instructions
HRT4-B
Battery Operated Electronic Room
Thermostat with Load Compensation (LC)
Temperature Control Software
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The HRT4-B is a battery powered electronic
room thermostat designed to provide optimum
comfort with close control of the energy used to
heat the home.
WARNING: ISOLATE MAINS SUPPLY BEFORE
COMMENCING INSTALLATION.
The HRT4-B will only operate when 2 x AAA
batteries have been fitted and the thermostat is
wired into your central heating system.
Installation and connection of the HRT4-B
must be carried out by a suitably qualified
person.
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The heating system will not work if a time switch or
programmer has switched it off.
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.
FOR THE USER
What is a room thermostat? ... an explanation
for householders
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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. 5

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.
The HRT4-B 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.
ADDITIONAL USER INFORMATION
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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.
USER INSTRUCTIONS
When the thermostat is in the ‘call for heat’ condition a
flame symbol will appear in the display. Further
information on how the thermostat operates is
contained in the ‘Explanation for householders’ that
precedes this section.
Pressing the temperature setting dial will
allow the user to check the current room
temperature which will be displayed for
approx 7 seconds before returning to the
set temperature. 7

The HRT4-B runs on 2 x type AAA (Alkaline)
non rechargeable batteries and is designed
to give a battery life of approximately two
years.
Battery Replacement
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.
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.
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INSTALLATION INSTRUCTIONS
The HRT4-B should be mounted on an internal wall
approximately 1.5 metres from floor level 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.
Positioning the Room
Thermostat
Warning isolate mains
supply before
commencing
installation.
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N.B. The wall plate must not be
altered or modified as it has been
specially designed to isolate the
mains supply when the thermostat
is removed to change the batteries.
Please dispose of old batteries
responsibly
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.
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.
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Once the wall plate has been removed from the
packaging please ensure the HRT4-B is re-sealed to
prevent damage from dust, debris etc. The wall plate
should be fitted with the wiring terminals located at the
top and in a position which allows a total clearance of at
least 50mm around the HRT4-B thermostat.
Fitting the Wall Plate
To remove the wall plate
from the HRT4-B undo
the two retaining
screws located on the
underside, the wall
plate should now be
easily removed.
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Wiring Box Mounting
Offer the plate to the wall in the position the HRT4-B 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 in position. The slots in the wall plate
will compensate for any misalignment of the fixings.
Direct Wall Mounting
The HRT4-B wall plate may be fitted directly on to a
single gang steel flush wiring box complying with
BS 4662:2006 + A1:2009, using two M3.5 screws. The
HRT4-B is suitable for mounting on a flat surface only; it
must not be positioned on an unearthed metal surface.
Electrical Connections
All necessary electrical connections should now be
made. Flush wiring can enter from the rear through the
aperture in the wall plate. For mains voltage
applications a 3 Amp fused spur should be used. The
recommended cable size is 1.0mm2. 12

FAILURE TO DO THIS COULD RESULT IN
ELECTRIC SHOCK WHEN CHANGING BATTERIES.
As access to the terminals will not be possible once the
terminal guard is fitted only fit the guard when all wiring
is complete and the system checked for correct
operation.
The wall plate is provided
with a terminal guard to
protect the user when
replacing the batteries.
This is supplied with the
wall plate and it is essential
that the terminal guard is
fitted after completing the
electrical connections to
the terminals of the wall
plate.
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HRT4-B Thermostat – Internal Wiring Diagram
The HRT4-B is double insulated and does not require
an earth connection, an earth connection block is
provided on the wall plate 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 wall plate.
ŸThe HRT4-B has voltage free contacts.
Please ensure that all
wiring complies with
t h e c u r r e n t I E E
regulations.
ŸThe HRT4-B is battery powered, therefore no mains
connection is required to power it.
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Typical combination boiler installation for boiler
with built in timer and external room ‘stat
This diagram is schematic and should be used for
guidance only. 15

Typical combination boiler installation with
ChannelPlus H11XL time switch and HRT4-B
room thermostat
This diagram is schematic and should be used for
guidance only. 16

Fully Pumped Heating System using HRT4-B room
stat, cylinder stat and Three Port Mid Position Valve
with a ChannelPlus H21/H27 electronic
programmer.
This diagram is schematic and should be used for
guidance only. 17

Fully Pumped Heating System using HRT4-B room
stat, cylinder stat and Two (2 Port) Spring Return
Valves with auxiliary switches and a ChannelPlus
H21/H27 electronic programmer.
This diagram is schematic and should be used for
guidance only. 18

Fitting the Thermostat to the Wall Plate
Ensure that the electricity supply to the HRT4-B is
switched OFF.
Swing the thermostat into position on the wall plate
without fitting the battery terminal guard. Tighten the 2
captive screws on the underside of the unit.
Ensure the terminal guard
is fitted into place over the
terminals of the wall plate
after procedure below.
Fit the two AAA batteries
provided, ensuring they are
instal le d c orrec tl y a s
indicated by the terminal
markings in the battery
compartment.
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Now switch ON the electrical circuit to the HRT4-B and
observe that it switches the heating system On and Off
as the temperature is turned up and down on the
thermostat. If the thermostat is switching the heating
system satisfactorily then switch the electricity supply
to the thermostat OFF, remove the thermostat from the
wall plate and fit the terminal guard over the terminals
on the wall plate.
Explain its operation to the householder before handing
over these instructions, highlighting the ‘explanation for
householders’ section on page 4.
Re-fit the thermostat into position on the wall plate and
tighten the 2 captive screws on the underside of the
unit. Switch on the electricity supply to the HRT4-B and
check again for correct operation.
Once clipped into position the terminal guard
cannot be removed from the wall plate.
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