Horstmann CentaurPlus C21 Series 2 Operation instructions

Two Channel Central Heating and Hot Water Programmer
The Horstmann CentaurPlus C21 two channel programmer
gives independent control over hot water and heating
with up to 3 ON/OFF settings per 24 hours.
It also has a 1 hour manual boost button for the hot water and
an advance button for the central heating.
There is also a programming switch allowing permanent selection of:
OFF/ON/AUTO/ALL DAY.
CentaurPlus C21 Series 2
User Operating Instructions
1

2
The CentaurPlus C21 Programmer
The simple instructions contained in this user guide are designed to help with the
programming and operation of the unit.
1 SET indicator - RUN is the normal position
2 Time of day
3 Switch period symbol
4 SET button
5 Hot Water BOOST or adjust (-) button
6 Central Heating ADVANCE or adjust (+) button
7 Hot Water (HW) programme select button or ENTER button
8 Central Heating (CH) programme select button
9 Hot Water ON indicator
10 Central Heating ON indicator
11 SET positions
12 PROGRAMME positions
13 BOOST symbol
14 ADVANCE symbol
15 AM/PM symbol
16 PROGRAMME indicators
1 15
11
3
9
12
4 5 6 7 8
216
13
14
10

Manual Overrides
BOOST FUNCTION - 1 HOUR TEMPORARY OVERRIDE (HOT WATER ONLY)
The boost facility will allow the user to boost the hot water channel which is currently
‘OFF’ for 1 hour. To indicate the boost being activated BOOST will be shown on the display
for the duration of the boost period. The hot water channel ON indicator will also be
illuminated.
ADVANCE FUNCTION – BRINGS FORWARD THE NEXT ON OR OFF OPERATION
(CENTRAL HEATING ONLY)
The advance facility will allow the user to switch the central heating channel ‘ON’ which
is currently ‘OFF’ or switch the central heating channel ‘OFF’ which is currently ‘ON’. To
indicate the advance feature being activated ADVANCE will be shown on the display
until the next programme switching time. The central heating ON indicator will also be
illuminated.
Fully Pumped or Gravity System
The installer will have set the programmer to suit the installed system. This is normally a
Fully Pumped system which will allow independent control of the central heating and hot
water, however on an old Gravity system the central heating and hot water are linked so
that it is not possible to use the central heating independently. This will allow only one
common time setting for both hot water and central heating, and will become apparent
when setting the ON and OFF times as both will be indicated together.
3
Press BOOST
button once
for 1 hour of
hot water
Press ADVANCE
button once to
move to the
next ON/OFF
time
At any time
during a BOOST
period press
BOOST again to
return to normal
programming
To cancel the
advance press the
ADVANCE button
again. This will
return the unit
to its normal
programme




AUTO
ALL DAY
24 HRS
OFF
HW CH
AUTO
ALL DAY
24 HRS
OFF
6:35
6:35
PM
PM
RUN
CLOCK
HW PROG
CH PROG
RUN
CLOCK
HW PROG
CH PROG
BOOST
ADVANCE
HW CH

Programme Override Facilities
With the CentaurPlus C21 programmer operating in the normal running mode it is possible
to alter the functionality of the programme on each individual channel by means of the
CH and HW buttons.
The options include;
AUTO - Channel follows all programmed ‘ON’ and ‘OFF’ times.
ALL DAY - Channel operates from 1st ‘ON’ time until 3rd ’OFF’, ignoring all
switching times in between.
24hrs - Channel will be constantly ‘ON’.
OFF - Channel will be constantly ‘OFF’, there is the ability to turn off the
heating during the summer without altering the programme times.
On the hot water channel the boost is still available. As both channels
are totally independent it is possible to have them set differently if
necessary.
All of the settings above will be permanent, i.e. unaffected by programme times, until
alteration by the user.
The diagram below illustrates how to alter the setting, it assumes that the channel is in the
AUTO mode to begin with.
Press HW or
CH once.
Programme
goes from
AUTO to
ALL DAY
Programme
will operate
from 1st ON
until 3rd OFF
period
Press HW or
CH again.
Programme
goes from
ALL DAY to
24 HRS
Programme
will be
continuously
ON
Press HW or
CH again.
Programme
goes from
24 HRS to OFF
Programme
will be
continuously
OFF
Press HW or
CH again.
Programme
goes from
OFF to AUTO
Programme
will return
to normal
ON and OFF
times

   
 
4
AUTO
ALL DAY
24 HRS
OFF
6:35
PM
HW CH HW CH HW CH HW CH
AUTO
ALL DAY
24 HRS
OFF
6:35
PM
AUTO
ALL DAY
24 HRS
OFF
6:35
PM
AUTO
ALL DAY
24 HRS
OFF
6:35
PM

5
Setting Time of Day and Date
Setting the On and Off Times
To alter these settings please proceed as follows:-
NB. The factory default settings for the 2nd ON/OFF times are both set at 12:00pm
(midday) which cancels this ‘ON’ period giving 2 ON/OFF periods for 24hrs. If a midday
‘ON’ period is required set the 2nd ON and OFF times accordingly. If not press ENTER twice.
Once the year is set and the
ENTER button is pressed the
process is complete and the
display will return to the run
position
Check that the correct time and day are
showing in the display. If the wrong day is
showing in the display that would indicate
that the date has not been set correctly and
the above process should be repeated
Press the
set button
until the set
indicator
is next to
the ‘clock’
position
Use the
+ and –
buttons
to adjust
the hour
and press
ENTER
Use the
+ and –
buttons to
adjust the
minutes
and press
ENTER
Use the
+ and –
buttons
to set
the date
and press
ENTER
Use the
+ and –
buttons
to set the
month
and press
ENTER
Use the
+ and –
buttons
to set
the year
and press
ENTER
    
1st ON 1st OFF 2nd ON 2nd OFF 3rd ON 3rd OFF
6.30AM 8.30AM 12.00PM 12.00PM 4.30PM 10.30PM
DEFAULT TIME SETTINGS
The default time settings shown above are preset at the factory
The CentaurPlus C21 series 2 programmer has a built in clock and calendar. This will mean
that you will need to enter the date as well as the time on initial set up or if the factory
re-set has been used. Having done this, the clock will automatically adjust for BST/GMT
time changes throughout the year.
Press the SET
button until
SET indicator is
next to PROG
position
Repeat this
process for
2nd and 3rd
settings
Use PLUS and
MINUS buttons
to adjust
1st ON time
Press the SET
button until
SET indicator
is returned to
RUN position
Use PLUS and
MINUS buttons
to adjust
1st OFF time
Press
ENTER
Press
ENTER



 
6:35
AM
ON
RUN
CLOCK
PROG
1


6
Resetting the Programmer
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 reset by pressing the SET and CH buttons together as
shown below.
After initial installation it is advisable, before programming the CentaurPlus for the first
time, to reset the unit. Resetting can only be achieved with the power ‘ON’ by pressing
the SET and CH buttons together. This will return the programmer to the factory set default
times.
SET
CH
Press the SET and CH buttons
together then release the buttons
and the programmer will return to
preset factory settings
General Information
BATTERY
The programmer is fitted with a non-rechargeable, long life battery, which will
maintain the programmed time settings for a minimum of ten months with the supply
disconnected.
THIS SHOULD BE SUFFICIENT TO COVER POWER INTERRUPTIONS DURING THE LIFE OF THE UNIT.
During power interruptions the display will be blank, after 3 days the current time of day
will be lost. These measures are to prolong the battery life.
SERVICE AND REPAIR
This programmer is NOT user serviceable. Please do not dismantle the unit.
In the unlikely event of a fault developing please refer to the RESETTING THE PROGRAMMER
section of this user guide shown above. If this fails to resolve the problem please contact a
local heating engineer or a qualified electrician.

7
... an explantion for householders.
Programmers allow you to set ‘On’ and ‘Off’ time periods. Some models switch the central
heating and domestic hot water on and off at the same time; while others allow the
domestic hot water and heating to come on and go off at different times.
Set the ‘On’ and ‘Off’ time periods to suit your own lifestyle. On some programmers you
must also set whether you want the heating and hot water to run continuously, run under
the chosen ‘On’ and ‘Off’ heating periods, or be permanently off.
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.
The heating will not work if the room thermostat has switched the heating off. And, if
you have a hot-water cylinder, the water heating will not work if the cylinder thermostat
detects that the hot water has reached the correct temperature.
What is a programmer?

Email: [email protected].uk
Website: www.horstmann.co.uk
Horstmann Controls Limited, Bristol BS4 1UP
Leaflet number P84362 – Issue 1
8