Horstmann CentaurStat 7 Operation instructions

Electronic 7
User Operating Instructions
The Horstmann Electronic 7 Water Heater Controller has been especially
developed to control the immersion heater as economically and conveniently
as possible.
During the night, water in the tank will be heated by cheap night-rate
electricity, ensuring a tank of hot water is available for the morning.
Depending on the size of the tank and usage of hot water, this will usually last
a day; however, if required, more hot water can be heated at any time by using
the ‘boost’ button which switches on the immersion heater for one hour.
Alternatively if it is known that extra hot water will be required every day, the
‘boost’ element (in the tank) can be programmed so that it will heat only a
small part of your tank. This is normally the upper element in the tank and can
be programmed to come on once each day at a set time.
Some tariffs offer additional cheaper electricity periods during the day time;
the Electronic 7 has extra off peak switching periods available to
accommodate this.
1

The Electronic 7 - an overview
The simple instructions in this user guide are designed to help you
with programming and operation of the unit.
2
LCD Display: The LCD display allows you to view the current time
and set programme times.
Indicators: Illuminated indicators give a visual feedback, indicating
the status of the programmes or boost operation.
Key: 1 - Timed display indicator 2 - LCD Display 3 - Boost Button
4 - Switched Output control
Manual Boost:
To use the manual boost, press the “BOOST” button on the unit
which will then boost your tank for 1 hour and then switch off.
THE BOOST WILL NOT OPERATE OR WILL BE CANCELLED
DURING TIMED HEATING PERIODS
BOOST
TIMED
OFF
TIMED
ELECTRONIC 7
SWITCHED
OUTPUT
SET MINUS PLUS SELECT
RUN
ISOLATE
MAINS
BEFORE
OPENING
OR
SERVICING
IMMERSION
HEATER(S)
SUMMER
WINTER
TIMED BOOST
CLOCK
BOOST PROGRAMME
OFF PEAK PROGRAMME
AM
12
3
4

Programme Security Lock
If the 4 black squares are showing in the display then this indicates
that the automatic programme of switching times has been locked on
installation and cannot be altered by the user. This will ensure that the
programme stays matched to any preferential tariffs which should
mean that your water is heated as economically as possible. The
manual boost button will still be operative allowing one hour of extra
hot water each time the boost is operated.
3
TIMED RUN SUMMER
WINTER
TIMED BOOST
CLOCK
BOOST PROGRAMME
OFF PEAK PROGRAMME
AM
Switched Output
In the “OFF” position the electrical supply to the immersion heater(s)
is disconnected even though the clock, display and indicator lights
continue to operate. In the “TIMED” position the over-night immersion
heater will be switched on and off at the programmed switch-time
settings, at other times the boost facility is available.
OFF
TIMED
SWITCHED
OUTPUT

Time Display
The Electronic 7 is fitted with an automatic clock that is pre-set on
manufacture and should not normally require any adjustments by the
user. The summer / winter setting is automatically selected and will
automatically change. This is indicated on the screen next to the
appropriate setting.
Therefore no adjustment is needed to be made by the user for the
summer / winter clock change. Should a minor correction to the clock
be necessary or if the unit has been reset then see the section on
Setting Time of Day.
On installation the installer will have selected whether the Electronic 7
will switch at GMT times throughout the year or whether the timings
need to alter as the clocks change.
For example:
GMT/BST – Switching time will be changed by one hour. In the
GMT/BST mode the clock display will match the actual switching time.
GMT ONLY – Switching will always take place at GMT times (summer
and winter). Although the clock display will show the correct time.
4
Setting Time of Day
Press the green
“SET” button
until the
indicator on the
left hand side
of the screen is
next to
“CLOCK”.
Adjust the hour
by pressing the
white “MINUS”
or “PLUS”
buttons. Once
you are happy
with the hour
selected, press
the blue
“SELECT”
button.
The minutes will
now flash. To
adjust the
minutes you
need to once
again press the
“MINUS” or
“PLUS” buttons.
Once you are
happy with the
time selected,
press the blue
“SELECT”
button, this will
now take it back
to the “RUN”
position on the
left hand side
of the screen.

Setting Off-Peak Heating Periods
5
Resetting the Unit
Sometimes electronic equipment can become scrambled or frozen. To
overcome this you should reset the unit. This can be achieved by holding down
“BOOST, MINUS, PLUS & SELECT” simultaneously.
The unit will now revert back to pre-set factory default off peak times and the
current time will show the time as it was at the time of re-set. The hour will be
flashing and should be adjusted as detailed in the section ‘Setting the time of
day’.
Press the green
SET button until
the indicator on
the left hand side
of the screen is
next to
“OFF PEAK
PROGRAMME”
The time hour will now
flash for the 1st on
time, this can be
adjusted by pressing
the “MINUS” and
“PLUS” buttons. Once
you are happy with the
hour you have selected
press the “SELECT”
button.
This will then make the
minutes flash, which
can be adjusted by
pressing the “MINUS”
and “PLUS” buttons
as required. Once you
are happy with the
minutes, press the
“SELECT” button to
take you to the 1st
off time
Use the “MINUS” and “PLUS”
buttons to adjust the hour. When
you are happy with the hour
selected then press the “SELECT”
button which shall now take you to
the minutes. Press the “MINUS”
and “PLUS” buttons to SELECT
the minutes you require and once
you are happy with the minutes
press the “SELECT” button.
The hour will be flashing on
the 2nd on time, if this is not
required then press the green
“SET” button which will take
you back to the main screen.
However, if you require any
further off-peak periods then
simply repeat the same steps
as above.
Default Time Settings
Default Times
1st ON 1st OFF 2nd ON 2nd OFF 3rd ON 3rd OFF
2:15am 7:15am 12:00am 12:00am 12:00am 12:00am
After re-setting the unit the off-peak heating times will revert back to the default
factory settings, these are shown above, however if you wish to change these
times please proceed as instructed in the Setting Off-Peak Heating Periods
above.

Programmed Boost
This setting is not recommended for single element installations and is
normally only used with twin or dual immersion heaters.
With the “TIMED BOOST” indicator on the right hand side of the screen
selected the boost, or upper element within the tank will heat up at the same
time automatically everyday. This can be turned on and off by pressing the
“SELECT” button.
6
To Set Boost Programme
Press the green SET button until the
indicator on the left hand side of the
screen is next to “BOOST PROGRAMME”.
The time hour will now flash for the on
time, this can be adjusted by pressing
the “MINUS” and “PLUS” buttons.
Once you are happy with the hour you
have selected, press the "SELECT"
button. This will then make the minutes
flash, which can be adjusted by pressing
the "MINUS" and "PLUS" buttons as
required.
Once you are happy with the minutes,
press the “SELECT” button to take you to
the off time. Use the “MINUS” and “PLUS”
buttons to adjust the hour. When you are
happy with the hour selected, press the
“SELECT” button which shall now take
you to the minutes.
Press the “MINUS” and “PLUS” buttons
to SELECT the minutes you require and
once you are happy with the minutes
press the “SELECT” button which will
take you back to the “RUN” position.
An indicator should be shown on the
right hand side of the screen next to
“TIMED BOOST”, if there isn’t then you
need to press the “SELECT” button.
Battery Reserve
The Electronic 7 is designed to be permanently connected to the mains
electricity supply. This unit has a non-rechargeable long-life battery which will
maintain the display and switch time settings for approximately 2 years with the
mains electricity supply disconnected. This should be sufficient to cover all
power interruptions during the life of the unit.
Neon Indicators
There are two neon indicators on this unit, one to indicate when the boost is
active and the other to indicate when the timed off-peak is active. With the
“SWITCHED OUTPUT SWITCH” in the “OFF” position the indicators lights will
still illuminate but no electrical switching will take place.

Service and Repair
The Horstmann Electronic 7 is not user serviceable, so please do not try to
dismantle the unit.
In the unlikely event of a fault developing try resetting the unit, which is in this
manual under “RESETTING THE UNIT”. If this fails to resolve the problem
then please contact your installer or a local heating engineer or a qualified
electrician.
7
Questions
(Q) There is no display on the screen?
(A) Ensure there is mains supply getting to the unit and that the battery switch
on the rear of the unit is in either the GMT/BST or GMT ONLY position.
(Q) The display has become frozen?
(A) This could be due to local electrical interference. Using the RESET
procedure in this manual may rectify the fault.
(Q) The neon indicator will illuminate but there is no hot water?
(A) Ensure the SWITCHED OUTPUT switch is in the TIMED position. If this still
fails to rectify the problem please contact a local heating engineer or a qualified
electrician.
(Q) How do I change the back-up battery?
(A) You can’t as it is an integral part of the unit, and therefore would invalidate
your guarantee if you dismantled the unit.
(Q) I want to adjust my off-peak times, how is this achieved?
(A) Please go to “SETTING OFF PEAK PERIODS” in this manual.
(Q) What does the indicator next to the word “TIMED BOOST” mean?
(A) If there is an indicator next to this word on the right hand side of the screen,
then this means the boost programme is selected. Please see “BOOST
PROGRAMME” in this manual.
(Q) Why are there 4 black squares showing in the display?
(A) The security feature has been engaged on installation to stop any
programme settings being altered by the user.
(Q) I cannot alter the programme times set into the Electronic 7.
(A) The programme security feature may have been engaged. This is shown
by 4 black squares showing in the display.

Part Number P83079 Issue 3
South Bristol Business Park,
Roman Farm Road, Bristol BS4 1UP
t: [phone]
e: [email protected]
www.horstmann.co.uk