Horstmann C-Stat 11-B User manual

C-Stat 11-B | C-Stat 17-B
Installation Instructions
Battery Powered Programmable
Room Thermostat
Programmable room thermostats are widely recognised as one
of the best ways in which to control central heating. Horstmann
C-Stat programmable room thermostats have a large display
and intuitive user interface, making them easy to set up and use.
C-Stat uses a sophisticated time proportional integral (TPI)
algorithm for accurate temperature control and energy
efficiency. Being battery powered, these models are suitable for
replacing most existing room thermostats.
Installation and connection should only be carried out by a
suitable qualified person and in accordance with the edition of
the IEE wiring regulation.
Warning: Isolate mains supply before commencing installation.
1

Positioning the C-Stat programmable room
thermostat
The C-Stat 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
access to the two retaining screws located at the base of
the wall plate
2
1.5m

Fitting the wall plate
To remove the wall plate from the C-Stat 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 C-Stat is resealed to prevent
damage from dust, debris etc.
The wall plate should be fitted in a position which allows a total
clearance of at least 50mm around the C-Stat programmable
thermostat.
Direct Wall Mounting
Offer the plate to the wall in the position the C-Stat 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 with compensate for any
misalignment of the fixings.
3
TOP
1 2 3 4 L N
1 2 3 4 LN
TOP

4
Wiring Box Mounting
The C-Stat wall plate may be fitted directly on to a single gang
steel flush wiring box complying with BS4662, using two M3.5
screws. The C-stat 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. The recommended cable size is 1.0mm².
Internal wiring diagram
The C-Stat 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 C-Stat has voltage free contacts
ŸThe C-Stat is battery powered, therefore no mains connection
is required to power it.
Please ensure that all wiring complies with current IEE
regulations
COMMON
CALL FOR
HEAT
C-STAT
1 2 3 4

1 2 34
E
N
L
ENL
Remove link
if Fitted
COMBINATION BOILER
TERMINALS
Mains
Supply
C-Stat
C-Stat controlling typical combination boiler installation.
For precise termination connection information please refer to the boiler manufactures
instructions
5
N L ON OFF ON OFF
HOT
WATER
CENTRAL
HEATING
PUMP
&
BOILER
Programmer
C-Stat
MAINS
SUPPLY
MAINS
SUPPLY
N
L
E
N
L
E
N
L
ROOM
STAT
SAT
CALL
SAT
CALL
CYL
STAT
C CN 1 2 3 4
C-Stat controlling a secondary heating zone on a fully pumped system with existing
programmer and two spring return valves with auxiliary switches

6
N L ON OFF ON OFF
HOT
WATER
CENTRAL
HEATING
PUMP
&
BOILER
Programmer
C-Stat
MAINS
SUPPLY
N
L
E
N
CALLSAT
CALL
CYL
STAT
C
W
BL
0
GR
L
SAT
1
3
4
C-Stat replacing a conventional room thermostat on a fully pumped system with an
existing programmer and two spring return valves with auxiliary switches
C-Stat replacing a conventional room thermostat on a fully pumped system with an
existing programmer and 3 port mid-position valve.
N L ON OFF ON OFF
HOT
WATER
CENTRAL
HEATING
Programmer
C-Stat
MAINS
SUPPLY
N
L
E
CALLSAT
CALL
CYL
STAT
C
SAT
1
3
4
PUMP
&
BOILER
NL

7
All wiring diagrams are schematic and should be used for guidance only.
INSTALLATION AND CONNECTION OF THE C-STAT MUST BE CARRIED OUT BY A
SUITABLY QUALIFIED PERSON.
WARNING: ISOLATE MAINS SUPPLY BEFORE COMMENCING INSTALLATION
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.
ŸFor Gas boilers set the TPI setting to 6 cycles per hour (default
setting)
ŸFor Oil boilers set the TPI setting to 3 cycles per hour
ŸFor Electric heating set the TPI setting to 12 cycles per hour
To adjust this setting go to the SET UP MENU and select TPI
CYCLES

8
Fitting the C-Stat to the wall plate
Fit the 2 x AA batteries provided under the hinged battery cover
on the front of the unit. Ensure they are fitted correctly as
indicated by the terminal markings in the battery compartment.
Complete the installation by swinging the C-Stat into position by
engaging the lugs at the top of the wall plate before pushing it
firmly 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 C-Stat. Explain its operation to the
householder and hand over the users operating instructions to
the user.

9
Installer Settings
There are a number of 'Installer Settings' that should be set on
installation.
These can be found under the 'SET UP MENU' on page 15 of
the user instructions.
The TPI Cycles setting and Optimum Start settings should be
carefully set on installation as this will affect system performance.
Clock Format AM/PM or 24 Hour clock display - Default
setting AM/PM
Daylight saving On or Off - Default setting ON for UK Market
Standby temperature Frost protection setting – Default setting 5°C
Upper and Lower Default settings 30°C and 5°C
Temperature limits
TPI Cycles This setting will change according to the
type of boiler being used - Default setting 6
For Gas boiler this setting should be 6
cycles per hour
For Oil boilers this setting should be 3
cycles per hour
For Electric panel heaters this should be 12
cycles per hour
Optimum Start On or Off – Default setting Off

10
Resetting the thermostat
Electronic equipment can in some circumstances be affected by
electrical interference.
If the display becomes frozen or scrambled simply press both
the BACK and ENTER button simultaneously.
BACK ENTER

11
Specification – C-Stat 11-B | C-Stat 17-B
Power Supply 2 x AA Batteries
Contact type Micro-disconnection
Wiring configuration Voltage free c/o contacts (SPDT)
Contact voltage rating 230V ac 50Hz (30V dc)
Contact current rating 8A (1A inductive)
Temperature differential 0.5°C
Temperature accuracy +/- 0.5°C to 21°C
Standards BS EN 60730-2-9
Dimensions (WxHxD) 120mm x 100mm x 26.5mm
Weight 0.3kg (approx)
Enclosure Flame retardant thermoplastic
Ingress protection IP30
Pollution degree Degree 2
Insulation class Class II (Double Insulated)
Software class Class A
Control type Type 2B
Temperature range 0°C to 40°C

Secure Controls (UK) Limited
South Bristol Business Park,
Roman Farm Road, Bristol BS4 1UP
E-mail: [email protected]
Web site: www.horstmann.co.uk
Part Number P84872 Issue 1
12