Horstmann CentaurStat 1 Operation instructions

Central Heating Programmable Room ThermoStat
The Horstmann CentaurStat 1 is a programmable room thermostat that
provides precise temperature control from a single point with up to 6
different temperature settings possible over a 24 hour cycle. Temporary
temperature adjustments can be made by means of the temperature
override buttons on the front of the unit.
CentaurStat 1
User Operating Instructions
1

2
The CentaurStat 1 Programmable ThermoStat
The simple instructions contained in this user guide are designed to help with the
programming and operation of the unit.
1 SET indicator
2 SET positions
3 SET button
4 OVERRIDE (MINUS) button
5 OVERRIDE (PLUS) button
6 ENTER button
7 Time or current temperature display
8 Target temperature
9 System ON symbol
10 PM indicator (no display for AM)
11 Temperature lock symbol
1 7
2
9
4
3
5
6
8
11
10
Located under ap

Target Temperature Override
Where an override temperature has been set, this altered setting will remain until the next
time and temperature setting is reached.
Target Temperature Lock
The temperature lock facility allows you to ‘lock in’ the target or override
temperature of the current heating period.
With the SET indicator in the RUN position press the ENTER button. The temperature
lock symbol will appear on the right hand side of the display. All control buttons
other than the ENTER button will be inoperative.
The locked temperature will now override all other temperature settings until the
lock is cancelled.
To cancel the temperature lock, and return to normal settings, simply press the
ENTER button.
If an override temperature had been
set before the lock was activated, the
altered setting will remain until the next
switching period is reached.
3
Manual Overrides
Ensure the SET
indicator is in the
normal RUN position
Use the PLUS and
MINUS buttons
to increase or
decrease settings
The CentaurStat
will operate on
this new setting
until the next time
period
 

Setting the Time of Day
When setting the time or altering the temperature settings, if a period exceeding
65 seconds is allowed to elapse between button presses then the CentaurStat will
automatically return to the run position. Any alterations made since the last press of the
ENTER button will not be recognised.
Time and Temperature Settings
The CentaurStat 1 has six temperature settings
per 24 hours.
These all have different start times and
temperature settings. The default factory settings
are shown opposite. Should you want to alter
these default times and temperatures, proceed
as per the instructions on page 5.
Display Features
The CentaurStat has two user displays, by pressing the PLUS and MINUS buttons
simultaneously, the user can toggle between either Display 1 or Display 2.
4
Press the SET
button until SET
indicator is next
to clock position
on the display
Use the PLUS
and MINUS
buttons to
adjust the time
Press
ENTER
Press the SET
button until
SET indicator is
returned to the
RUN position

DEFAULT SETTINGS
Period Times Temps.
1 6:00am 20ºC
2 8:30am 18ºC
3 11:30am 20ºC
4 1:30pm 18ºC
5 5:00pm 21ºC
6 10:00pm 15ºC
Display 1 - Shows current time
and target temperature
Display 2 - Shows current and
target temperature

Changing the Times and Target Temperatures
Press the SET button until
SET indicator is next to
the PROG position
The time setting for the 1st
period will now flash.
Use the PLUS and MINUS buttons
to alter the start time if required
Repeat for remaining 5 time
and temperature periods
Press the SET button until
the SET indicator is returned to
the RUN position
The target temperature setting
for the 1st period will now flash.
Use the PLUS and MINUS buttons
to alter the target temperature
if required
Press ENTER
Press ENTER
    
5

Reducing the Number of Time and
Temperature Settings
To reduce the number of temperature settings available in a day from six to four, proceed
as follows:
Set the 3 and 4 period temperatures to the same temperature as set on period 2.
Periods 1 and 2 will now operate as normal.
For two settings per day, set the temperature on periods 2, 3, 4 and 5 to the same
temperature as set on period 1.
For one setting per day use the Target Temperature Lock procedure located on page 3
of this user guide.
Battery Replacement
Your CentaurStat is battery operated. The
batteries supplied with the unit should last for
approximately two years.
When the batteries are nearing the end of their
life a BATTERY LOW symbol will ash on the
display (see diagram opposite).
Isolate any external electricity supply to your CentaurStat
before replacing the batteries
Press the RELEASE BUTTON on the right hand side of the unit and swing the front cover
away from the mounting plate by gently pulling on the right.
Remove the old batteries (with the batteries removed your CentaurStat will retain its
programme for approximately ve minutes) and replace them with three new AA size
alkaline batteries, ensure they are tted correctly as shown on the label positioned
between the battery terminals (see diagram).
Once batteries have been tted, offer the left hand side of the unit up to the mounting
plate ensuring that the two guide lugs are tted into the corresponding slots in the side of
the mounting plate.
Now swing the right hand side of the CentaurStat up against the mounting plate until the
release button clicks into place. After a few seconds the display will automatically return to
your CentaurStat.
PLEASE NOTE:
If the battery tting time has exceeded ve minutes some time and temperature
adjustment may be necessary, please refer to the relevant sections located on page 4 and
5 of this user guide.
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7
Resetting the CentaurStat
Electronic equipment can in some circumstances be affected by electrical interference. If
the programmer’s display becomes frozen or scrambled; or if you wish to revert back to
the default time settings please use the following procedure.
Lower the ap and press the SET and ENTER buttons together,
release the buttons and the CentaurStat will return to preset
factory default time settings.
Service and Repair
This product is NOT user serviceable. Please do not dismantle the unit.
In the unlikely event of a fault developing please refer to the RESETTING THE CENTAURSTAT
section of this user guide located above. If this fails to resolve the problem please contact
a local heating engineer or a qualied electrician.
Battery Replacement Diagrams:

Email: [email protected].uk
Website: www.horstmann.co.uk
Horstmann Controls Limited, Bristol BS4 1UP
Leaflet number P82161 – Issue 2
8
... an explantion for householders.
A programmable room thermostat is both a programmer and a room thermostat.
A programmer allows you to set ‘ON and OFF’ time periods to suit your own lifestyle.
A room thermostat works by sensing the air temperature, switching on the heating when the air temperature
falls below the thermostat setting and switching it off once the set temperature has been reached.
So, a programmable room thermostat lets you choose what times you want the heating to be on, and what
temperature it should reach while it is on. It will allow you to select different temperatures in your home at
different times of the day (and days of the week) to meet your particular needs.
Turning a programmable 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 the boiler and
radiators.
Neither does the setting affect how quickly the room cools down. Turning a programmable room thermostat to a
lower setting will result in the room being controlled at a lower temperature, and saves energy.
The way to set and use your programmable room thermostat is to find the lowest temperature settings that you
are comfortable with at the different times you have chosen, and then leave it alone to do its job. The best way
to do this is to set low temperatures first, say 18ºC and then turn them up by one degree each day until you are
comfortable with the temperatures. You won’t have to adjust the thermostat further. Any adjustments above
these settings will waste energy and cost you more money.
If your heating system is a boiler with radiators, there will usually be only one programmable 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 chose 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.
The time on the programmer must be correct. Some types have to be adjusted in spring and autumn at the
changes between Greenwich Mean Time and British Summer Time.
You may be able to temporarily adjust the heating programme, for example, ‘Override’, ‘Advance’ or ‘Boost’.
These are explained in the manufacturer’s instructions.
Programmable 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.
What is a programmable room thermostat?