Potterton Gold 4 kW User guide

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ELECTRIC BOILERS - 4, 6, 9, 11 & 12kW MODELS
RADIATOR & UNDERFLOOR VERSIONS
INSTALLATION AND SERVICING INSTRUCTIONS
PACK CONTENTS
The POTTERTON GOLD electric boiler
Guarantee registration card
Fitting & user instructions
IMPORTANT: PLEASE READ AND UNDERSTAND THESE INSTRUCTIONS
BEFORE COMMENCING INSTALLATION. PLEASE LEAVE THIS MANUAL
WITH THE CUSTOMER FOR FUTURE REFERENCE.

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THANK YOU FOR PURCHASING THIS POTTERTON GOLD ELECTRIC BOILER. IT HAS BEEN DEVELOPED
TO PROVIDE YOU WITH MANY YEARS OF TROUBLE-FREE SERVICE WHEN INSTALLED CORRECTLY
PLEASE READ AND UNDERSTAND THESE INSTRUCTION PRIOR TO INSTALLING YOUR POTTERTON GOLD
ELECTRIC BOILER. THIS POTTERTON GOLD ELECTRIC BOILER MUST BE INSTALLED, COMMISSIONED
AND MAINTAINED BY A COMPETENT PERSON ONLY. FOLLOWING INSTALLATION AND COMMISSIONING
THE OPERATION OF THE BOILER SHOULD BE EXPLAINED TO THE USER AND THESE INSTRUCTIONS LEFT
WITH THEM FOR FUTURE REFERENCE.
THIS APPLIANCE IS NOT INTENDED FOR USE BY PERSONS (INCLUDING CHILDREN) WITH REDUCED
PHYSICAL, SENSORY OR MENTAL CAPABILITIES, OR LACK OF EXPERIENCE AND KNOWLEDGE, UNLESS
THEY HAVE BEEN GIVEN SUPERVISION OR INSTRUCTION CONCERNING USE OF THE APPLIANCE BY A
PERSON RESPONSIBLE FOR THEIR SAFETY.
INTRODUCTION
FIGURE ONE: MAIN COMPONENTS OF POTTERTON GOLD ELECTRIC FLOW BOILER
OUTLET
RED IDENT
ELECTRICAL CABLE
ENTRY POINTS
EARTH CLAMP
TERMINAL BLOCK
MAIN PCB
BOILER ELEMENT
INSULATION
TEMPERATURE SWITCH
INLET
FRONT COVER (TOP)
WARNING LABEL
INSULATION SHEET
FLYING LEAD
CONTROL PANEL
FRONT COVER (BOTTOM)
RATING LABEL
SERIAL NUMBER

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The POTTERTON GOLD electric boiler is designed to heat re-circulated water used in wet central
heating systems. The water is heated when it is passed over electric immersion elements, which are
contained in a chamber. The temperature of the water is monitored and controlled by a modulation
technique switching on the immersion elements. The switching of the elements is carried out by
solid-state technology contained in the control section of the boiler. The operation of the boiler can
be controlled by standard programmers, room thermostats, etc. The pump should be connected to
the boiler control, which provides the run-on facility.
DESCRIPTION
Output Temperature Control Range: (Radiator) 650C to 800C.
(Underfloor) 300C to 600C
Operating voltage 200V - 245V 50Hz
Pump supply fuse (internal) T 2A 240V - 20x5mm.
‘RUN’ control input signal requires 200V - 245V 50Hz
‘RUN’ control input signal draws less than 0.25A. 10mA typical.
Optical isolation Between the control signals
and the boiler supply.
Over temperature trips 95 and 1000C
Water content 1.3 litres
Product code Boiler type 220V / Btu 240V / Btu Size
94022008 Rad 4kW 3.5kW / 11,900Btu 4kW / 13,600Btu 1050 x 90 x 90mm
94022108 U/floor 4kW 3.5kW / 11,900Btu 4kW / 13,600Btu 1050 x 90 x 90mm
94022004 Rad 6kW 5kW / 17,000Btu 6kW / 20,400Btu 1050 x 90 x 90mm
94022104 U/floor 6kW 5kW / 17,000Btu 6kW / 20,400Btu 1050 x 90 x 90mm
94022005 Rad 9kW 7.5kW / 25,600Btu 9kW / 30,700Btu 1050 x 90 x 90mm
94022105 U/floor 9kW 7.5kW / 25,600Btu 9kW / 30,700Btu 1050 x 90 x 90mm
94022006 Rad 11kW 9kW / 30,700Btu 11kW / 37,500Btu 1050 x 90 x 90mm
94022106 U/floor 11kW 9kW / 30,700Btu 11kW / 37,500Btu 1050 x 90 x 90mm
94022007 Rad 12kW 10kW / 34,000Btu 12kW / 40,900Btu 1050 x 90 x 90mm
94022107 U/floor 12kW 10kW / 34,000Btu 12kW / 40,900Btu 1050 x 90 x 90mm
Electric boiler for wet central heating systems.•
Domestic hot water is available from a cylinder.•
Can be used in a sealed or open vented system installations.•
No flue or fuel tank required.•
Quiet in operation.•
Operates from standard mains voltage programmers, room thermostats, etc.•
Pump run-on facility.•
Solid-state technology enables zero volt switching.•
Soft start and soft modulation.•
Front panel operation indicators.•
User adjustment of the operating temperature on the front panel.•
Self check every time it operates.•
Optical isolation to enable connection of more boilers on single or three phase supplies.•
Electrical tails terminations inside the boiler.•
Safety trip for no water or no flow situations.•
FEATURES
TECHNICAL SPECIFICATION

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Care must be taken when handling and connecting the boiler not to damage or stress it in any way.
Prior to installation the boiler must be stored in a dry, safe place.
The boiler must be mounted in an UPRIGHT position. The boiler must be fixed to a wall before
connecting pipework. When choosing the position for the boiler, ensure sufficient clearances to
house the unit and for servicing. 50mm minimum clearance each side of the boiler is required. A
drain valve at the base of the boiler is strongly recommended. It must be sited in a dry, ventilated
position, frost free and not subjected to extremes of temperature.
Note: Before connecting the pipework, ensure the rubber seal at the top of the boiler is firmly in place;
check it has not become loose in transit. The warranty will be invalid if water leaks into the boiler.
INSTALLATION - GENERAL
TOP HAUT ALTO OB EN
WARNING
Before obtaining acce ss to term inals all supply
circuitsm ust be di sconnected
Donot so lder directly onto flow and r eturn pipe work
Thegua rantee will be withdrawn if this product is
Notinsta lled ina ccorda nce with the installation
instructions
FIGURE TWO: DIMENSIONS
BACK VIEW
FRONT VIEW
SIDE VIEW
ENTRY PORTS
SUPPLY AND
CONTROL ON
BOTH SIDES
20mm 25.4mm
FLOW PIPEWORK
RED IDENT
RETURN PIPEWORK
5mm SECURING
HOLE
900mm FIXING CENTRES
30mm
1050mm
20mm
30mm
100mm
90mm

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The installation must be carried out in accordance with the relevant requirements of:
The appropriate Building Regulations, either The Building Regulations, The Building Regulations
(Scotland) or Building Regulations (Northern Ireland)
The Water Fittings Regulations or Water Byelaws in Scotland.
IT IS THE INSTALLER’S RESPONSIBILITY TO ENSURE THAT THE INSTALLATION DOES NOT CONTRAVENE
THE REQUIREMENTS OF THE WATER SUPPLY REGULATIONS, BUILDING REGULATIONS OR LOCAL
AUTHORITY REGULATIONS.
The boiler must be installed by a qualified, competent tradesman who is aware of and will comply with
all relevant standards that are applicable: e.g. Building Regulations, the Local Authority Regulations,
the Water Supply Regulations and undertaking the relevant British Standards. The system must be
flushed in accordance with BS 7593 and in accordance with the supplied instructions and drawings
to ensure proper operation.
The boilers contain a very small amount of water, and so require a sufficient flow rate of water to
ensure proper operation. The 4kW and 6kW product requires a minimum flow of 6 litres/minute,
and the 9kW, 11kW and 12kW require a minimum flow of 12 litres/minute. Insufficient flow of water
through the boiler will cause nuisance trip outs. The maximum temperature differential between
input and output of the boiler must not exceed 140C. If the temperature across the boiler exceeds
this then the flow rate is too low and will potentially damage the boiler. Set the flow rate to give 5 -
100C across the boiler on full heat.
The output FLOW pipe at the TOP of the boiler is identified RED. The input RETURN pipe is located
at the BOTTOM. Ensure that the direction of flow is correct through the boiler after installation. Set
the pump on maximum flow rate.
Pipework connections on all models are 22mm.
Use standard size pipework. DO NOT SOLDER DIRECTLY ONTO THE BOILER TAILS. Push-on or
compression fittings are suitable for connecting directly onto the boiler tails. Fit a 22mm elbow to the
top of the boiler and after 100 – 150mm of horizontal pipework fit an automatic air vent, or connect
the expansion pipework on open vented systems to provide a route for air to vent. DO NOT FIT THE
AAV DIRECTLY ABOVE THE BOILER.
The electric boiler is suitable for operation in sealed or open vented systems. It is also suitable for
schemes such as heating only, Y plan, S plan, zone heating, under floor heating, micro-bore via a
manifold, etc. If you are unsure about your application regarding suitability of the boiler, please do
not hesitate to contact your local supplier or Potterton Gold directly.
The cost of installation can be reduced if the electric boiler is used for heating only. Use a direct
type cylinder with immersion elements and a time clock for the domestic hot water, then connect the
electric boiler directly to the heating circuit and control it by a programmable room thermostat. If the
radiator circuit has a continuously open route for the water flow, then a bypass is not required. The
boiler sizing is for heating only in this case and does not have to be increased to allow for domestic
hot water as well.
Ensure there is always an open route for the water to flow in any installation, to meet the required
minimum flow rate of the boilers and to allow for the pump over run. If an open route through the
heating circuit can not be guaranteed, then a bypass, fitted with an automatic bypass valve, must be
fitted which meets the required minimum flow rates for the boiler.
The bypass must have a minimum of either 2 metres of 22mm continuous pipework, or be routed
through a radiator with minimum dimensions of 600 x 600mm. Automatic pressure opening valves
must be used with the bypass circuit, ensure they are installed correctly as per the manufacturer’s
instructions. Gate valves are not suitable. DO NOT FIT A VALVE BETWEEN THE BOILER AND THE SAFETY
PRESSURE RELIEF VALVE OR EXPANSION RELIEF SYSTEM.
INSTALLATION - PLUMBING

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The boilers are suitable for operating pressures up to 3 bar. Normal sealed systems operate at 1 to 1.5
bar. Ensure a safety pressure relief valve is fitted to all sealed systems. With open vented installations,
ensure there is a sufficient head of water for the pump to supply the full flow through the boiler of
at least 1½ metres between the bottom of the feed & expansion tank and the top of the boiler.
NOTE: TO COMPLY WITH BUILDING REGULATIONS, PART L (PART J IN SCOTLAND), WHEN THE ELECTRIC
BOILER IS USED FOR CENTRAL HEATING PURPOSES, A ROOM THERMOSTAT MUST BE FITTED TO
CONTROL THE BOILER (SEE PAGE 15).
Do not fit thermostatic radiator valves to the room with the control thermostat, other rooms may be
fitted with thermostatic radiator valves.
DO NOT OPERATE UNDER THERMOSTATIC RADIATOR VALVES ONLY.
Use standard pumps, controls, room thermostat, valves, etc. The main electrical power (high current)
must be routed directly to the boiler via an MCB and RCD, not through the controls. Only a control
signal to the boiler comes from the programmer. The switching of the high power current is done
inside the boiler.
For installations with more than one boiler, mount the boilers side-by-side with a minimum of 50mm
gap between each boiler, output flow tails at the top and the returns at the bottom. ‘Tee’ in the
flows together, increasing in pipe size at each boiler to ensure full flow to each boiler. E.g. for 3 x
12kW boilers, first boiler use a 22mm elbow to the second boiler. Second boiler tee 22mm in from
first boiler, 22mm branch to second boiler, 28mm to third boiler. Third boiler tee 28mm in from
second boiler, 22mm branch to third boiler, 35mm away to heating circuit. Repeat for the return
connections. Single pump in the 35mm flow line, ensure sufficient flow for all 3 boilers, i.e. (for 3
x 12kW boilers requires 3 x 12 l/m = 36 litres/minute minimum). Do not reduce pipework before
‘teeing’. See figure four on page 8.
When filling the system check for leaks. THE WARRANTY WILL BE INVALIDATED IF WATER LEAKS INTO
THE BOILER. ENSURE ALL JOINTS ABOVE THE BOILER ARE SOUND.
After installation the system must first be flushed out in accordance with BS 7593:1992 before
adding the inhibitor. Fernox “Superfloc”, or BetzDearborn Setinel X300 or X400 are ideal flushing
agents for new and existing systems. After flushing the correct amount of inhibitor must be added
before use. Fernox “Superconcentrate”, or MB-1, or BetzDearborn Sentinel X100 can be used for most
water areas, however we recommend you should check with your local water authority to ensure
suitability. Check the inhibitor concentration after installation and periodically thereafter to ensure
correct protection.
FAILURE TO FLUSH PROPERLY OR INADEQUATE INHIBITOR IN THE SYSTEM WILL INVALIDATE THE
WARRANTY.

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FIGURE THREE: BASIC PLUMBING LAYOUT
AUTOMATIC AIR VENT EXPANSION / SAFETY
RELIEF SYSTEM
SERVICE VALVE
PUMP
ISOLATING VALVE
150mm MINIMUM
2 METRES MINIMUM
ELECTRIC BOILER
AUTOMATIC
PRESSURE
BYPASS VALVE
FLOW
RETURN
DRAIN VALVE
ALTERNATIVE BY-PASS ARRANGEMENT
USING THE BATHROOM RADIATOR FITTED
WITH TWO LOCKSHIELD VALVES
OPEN VENTED SYSTEMS MUST
HAVE A MINIMUM HEAD OF
1.5 METRES AND MAXIMUM
HEAD OF 30 METRES

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A typical plumbing schematic connecting 3 x 12kW boilers together.
NOTE:
The increase in pipework sizing to ensure proper flow through the boilers.•
Ensure there are no restrictions in the heating circuit such as thermostatic radiator valves etc.•
The expansion vessel has not been shown on this schematic.•
For 2 x 12kW boilers, 28mm pipework flow and return is required.•
A bypass must be fitted. Preference should be made for a 600 x 600 radiator.•
FIGURE FOUR: THREE BOILER PLUMBING SCHEMATIC
AUTOMATIC AIR VENT EXPANSION / SAFETY
RELIEF SYSTEM
SERVICE
VALVE
PUMP
ELECTRIC BOILER
FLOW
DRAIN VALVE
ELECTRIC BOILER
ELECTRIC BOILER
35mm PIPE
FLOW
36 LITRE/
MIN
28mm PIPE
FLOW
24 LITRE/
MIN
22mm PIPE
FLOW
12 LITRE/
MIN
35mm PIPE
FLOW
36 LITRE/
MIN
28mm PIPE
FLOW
24 LITRE/
MIN
22mm PIPE
FLOW
12 LITRE/
MIN
RELAY
SYSTEM
94970058
RETURN

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ALL WIRING MUST BE CARRIED OUT IN ACCORDANCE WITH CURRENT IEE WIRING REGULATIONS.
The POTTERTON GOLD boiler must be installed by a qualified competent tradesman in accordance
with supplied instructions and drawings to ensure correct operation.
Check the main incoming supply to the property to ensure there is sufficient current and voltage
for the size of the boiler or boilers to be installed. Remember to also take account of the supply
requirements for the rest of the property. Ensure the correct cable size is used to feed the boiler
(refer to IEE wiring regulations).
A double pole RCD with a trip level sensitivity of 30mA and capable of breaking the full load current
to BS EN 61008:1994, must be used.
In order to provide a means of isolation, the boiler must be connected to the supply through a double
pole linked switch with a minimum contact gap of 3mm in all poles. The RCD is suitable for this
requirement if it is mounted in close proximity to the boiler.
A correctly rated MCB must be used in the supply, see Technical Specifications (page 3). An additional
3A supply is required for the controls etc. NOTE, a blank must be fitted between each MCB to provide
ventilation, check with the MCB manufacturer/supplier.
NOTE: The high current mains supply MUST NOT be routed through the programmer, controls etc.
Follow the wiring diagrams. Use a standard programmer, room thermostat, etc. The high current
switching is carried out inside the boiler, only standard switched live (low current) control signals
are supplied by the programmer etc.
Electrical Connections
Access can be gained to the electrical connections by removing the top front panel.
CONN 5: MAIN POWER. Main power-supply cables. Connect the power cables from the power1.
“supply” (CONN 5) terminals on the PCB assembly in the boiler directly to the isolation switch, live,
neutral and earth. Use the correct rated cable. Do not connect the power through the programmer,
thermostats etc. The main power PCB terminals in the boiler are suitable for cables up to 10mm2.
NOTE: THESE CONNECTIONS MUST BE TIGHT. LOOSE CONNECTIONS WILL CAUSE BURNING AT
CONN 5 CONNECTOR, THIS IS NOT COVERED BY THE WARRANTY.
CONN 1 pins 2 & 3: CONTROL SIGNAL. Connect switched live to ‘R’ and neutral to ‘N’ on the2.
control terminal block in the boiler to the switched live and neutral from the programmer control
circuit. A neutral must be connected, as this control signal is optically isolated from the main
supply in the boiler and will not run without a neutral. Do not connect any wires to the terminal
marked N/C.
CONN 1 pins 4, 5 & 6: PUMP CONNECTIONS. The supply to the pump must be connected to the3.
‘PUMP’ terminal on the control terminal block in the boiler. This supply is fused in the boiler at
2A.
Cable access is made from either the right or left hand side via the x3 knockouts provided (x14.
25mm for power and x2 20mm for pump and thermostat cables). Having decided which side to
route the cables, remove x3 knockouts only (This can be achieved with a small tap from a ball
nose hammer, then twisting the knockout untill it is removed. Note: Take care not to damage the
casing, ensure the metal discs are retrieved and no sharp edges are present. The cables should
be installed using a cable compression gland (not supplied).
INSTALLATION - ELECTRICAL REQUIREMENTS
x3 KNOCKOUTS
LEFT HAND SIDE
X3 KNOCKOUTS
RIGHT HAND SIDE
FIGURE FIVE: CASE KNOCKOUTS
FIGURE SIX: TWISTING KNOCKOUT

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Connections for 2 or more boilers.
1 CONN 5: Main power-supply cables. Connect each boiler to its supply live, neutral, and earth,
as described above. The supplies to each boiler can be on different phases if using a 3-phase
supply.
2 CONN 1 pins 2 & 3: Control signal. Join all the boiler ‘R’ terminals on the control terminal
block together, and then connect them to the switched live control signal to the programmer
control circuit. Connect all the boiler ‘N’ terminals on the control terminal block together and
then to neutral on the programmer control circuit.
3 CONN 1: Pump connections. The pump must be connected through a relay assembly to
ensure that the pump always operates if any one boiler is running. See page 26. Relay
box 94970057 is required for a two boiler system and 94970058 is required for a 3 boiler
system.
Check the main electrical power connections are tight. Support the back of the PCB behind the power
terminals when tightening the main power terminals. Loose connections can cause burning at the
connectors and will invalidate the warranty.
The control RUN signal is optically isolated from the main boiler supply to enable different phases to
be used between boilers. The control signal required to operate the boiler is 220V - 240V at a very
low current, typically 10mA.
WARNING: THIS APPLIANCE MUST BE EARTHED.
All exposed pipework must be earthed in accordance with IEE Regulations.
After installation, preliminary electrical checks i.e. short circuit, earth continuity, resistance to earth
and check for correct polarity etc. must be carried out.
Before connecting the electrical supply, ensure the system is full of water and set to the correct
pressure (sealed systems), check for leaks. It is essential that all the air is purged from the system.
Only then can the supply be switched on.
On completion of the work the installation must be tested to IEE Regulations and an NICEIC Inspection
and Completion Certificate must be issued.
Please take note of the installation information. If in doubt please contact your local supplier or
Potterton Gold.
FIGURE SEVEN: BOILER INTERNAL SCHEMATIC
N E L
CONN5
N R E N L
CONN1
CONTROL
ELEMENT

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FIGURE EIGHT: BOILER SUPPLY USING EXISTING CONSUMER UNIT
N E L
N R E N L
CONN1 CONN5
CONSUMER UNIT
MCB MCB MCB
AIR
GAP
PUMP
ELECTRIC BOILER
N L
MAINS SUPPLY
DOUBLE POLE
RCD OR DOUBLE
POLE ISOLATION
LOCAL TO BOILER
DOUBLE POLE
ISOLATION SWITCH
OR DOUBLE POLE
RCD
3A FUSED
SPUR OR MCB
HEAT RESISTANT
CABLE
DEMAND SIGNAL
FROM CONTROLS/
PROGRAMMER ETC
(SEE TYPICAL
WIRING DIAGRAMS)
TO CONTROLS
PROGRAMMER / ETC
EARTH BONDING
TO BE PERFORMED
IN ACCORDANCE
WITH BS7671
BOILER SUPPLY
MCB
L
N

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FIGURE NINE: BOILER WIRING DIAGRAM
NO CONNECTION
PUMP SUPPLY CABLE
0.5mm - 1mm
MAINS SUPPLY CABLE
Refer to BS7671 for cable sizing
BOILER CONTROL CABLE
0.5mm - 1mm
SUPPORT BACK
OF PCB WHEN
TIGHTENING SCREWS
ENSURE SCREWS
ARE TIGHT.
LOOSE CABLE
CONNECTIONS
CAN CAUSE BURNING
AT THE CONNECTOR
SUPPLY
CONN 5
CONN 1
FS 1 2A 240V
(5 X 20mm)
REMOVE TOP COVER ONLY TO
GAIN ACCESS TO THE
CONNECTIONS ON THE PRINTED
CIRCUIT BOARD INSIDE THE
BOILER HOUSING
LIVE EARTH NEUTRAL
LIVE EARTH NEUTRAL RUN NEUTRAL
NL
CONTROL PUMP
CONTROL PUMP
NC N R E N L
NC N R E N L
CASE EARTH
22
22

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FIGURE TEN: TYPICAL S PLAN WIRING DIAGRAM
ROOM STAT CYLINDER STAT
BLUE
GRN/YLW
BROWN
GREY
ORANGE
2 1 3 1 C 2
E
N
L
N
RUN
TO
BOILER
L N CH ON HW ON CH OFF HW OFF
FROM 3A
FUSED SPUR
OR MCB
1 2 3 4 5 6 7 8 9 10
TIME CONTROLLER
BLUE
GRN/YLW
BROWN
GREY
ORANGE
2 PORT VALVES

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FIGURE TWELVE: TYPICAL HEATING ONLY WIRING DIAGRAM
ROOM STAT
CYLINDER
STAT
BLUE
G/YELLOW
WHITE
GREY
ORANGE
2 1 3 C 1 2
E
N
L
N
RUN
TO
BOILER
L N CH ON HW ON CH OFF HW OFF
FROM 3A
FUSED SPUR
OR MCB
TIME CONTROLLER
FIGURE ELEVEN: TYPICAL Y PLAN WIRING DIAGRAM
1 2 3 4 5 6 7 8 9 10
1 2 3 4 5 6 7 8 9 10
MID POSITION
VALVE
E
N
L
N
RUN
TO
BOILER
FROM 3A
FUSED SPUR
OR MCB
PROGRAMMABLE ROOM
THERMOSTAT
A B C

15
Heating Controls To Comply With The Revised Building Regulations (Part L For England. Part J for
Scotland).
New Dwelling
1. The installation must be a fully pumped system.
2. Independent temperature and time controls for both heating and domestic hot water.
3. Controls to interlock with the boiler. TRV’s alone do not comply.
4. An automatic bypass must be used if a bypass is required. Gate-valves do not comply.
5. Split heating circuits into zones: -
a. Room thermostat or programmable room thermostats in all zones.
b. A room thermostat or programmable room thermostats in the main zone and TRV’s in all
other zones.
6. Cylinder thermostat and zone valve to control stored hot water. Non-electric hot water controllers
do not comply.
7. Timed controller for heating and hot water must be provided.
8. A minimum of 2 zones for heating floor spaces greater than 150m2.
9. Boiler management control systems meeting specific zoning, timing and temperature requirements
are acceptable.
Existing Dwellings
When a new installation is fitted, the controls must be as for a new dwelling.
When replacing the boiler and/or hot water vessel, the opportunity to improve the controls should
be considered to be confident that the requirements of the Building Regulations are met.
INSTALLATION - REVISED BUILDING REGULATIONS

16
The boiler controls are fully automatic, making the operation very simple.
Only after the system has been flushed through and then filled with water, inhibitor and set to the
correct pressure (sealed systems), can the electrical supply be switched on.
Check 1. When filling the system check for leaks. The warranty will be invalidated if water leaks
into the boiler. Ensure the joints above the boiler are sound.
Check 2. Before switching on the mains supply, check the main electrical power connections
are tight. Support the back of the PCB behind the power terminals when tightening
the main power terminals. Loose connections can cause burning at the connectors.
Initial set up procedure: -
Ensure the main electrical supply and the programmer controls to the boiler are off and1.
isolated.
Remove the pump live and neutral connection from the control terminal block in the boiler, and2.
reconnect the pump live wire into the control terminal ‘R’ together with the control signal wire.
Connect the pump neutral wire into the control terminal ‘N’ together with the control neutral
wire.
Unplug the control block from the main PCB, ensure it is safe and not touching anything. The3.
pump is now fed from the control signal.
Check all air is purged from the system, and set the pump to maximum.4.
Switch on the control supply only (3 amp or 6 amp) MCB.5.
With the programmer and room thermostat on, check the pump is running and water is flowing.6.
Ensure the whole system, valves etc. are operating correctly. Continue to run the pump for some
time to purge any air. Don’t forget to bleed the pump.
Switch off the main supply RCD and MCB’s. Ensure it is all safe before reconnecting the pump7.
connections to the pump terminals as was originally wired. Reconnect the control terminal block
onto the PCB. Check all connections are made correctly, check the main supply terminals in the
boiler are tight, close and secure the top front cover of the boiler.
Main test procedure: -
Only after a satisfactory initial test, proceed as follows; -
Switch on the main boiler MCB.1.
Switch on the programmer “control” (3 amp or 6 amp) MCB.
Switch on the RCD unit/Isolation switch.
Check the boiler front panel SUPPLY indicator is illuminated (green).
Set the programmer for central heating to ON.2.
Set the room thermostat to be ON.
The boiler front panel CALL indicator will flash (green).
This indicator will illuminate as a steady green after approximately 2-3 minutes.
Following the steady green, the HEAT indicator will build up gradually.
Check the temperature of the3. FLOW pipework from the boiler. This pipework should start to rise
in temperature. The rate of rise will depend upon the size of the boiler and system.
COMMISSIONING

17
FIGURE THIRTEEN: INITIAL TEST SET UP
NO CONNECTION
PUMP SUPPLY CABLE
0.5mm - 1mm
MAINS SUPPLY CABLE
Refer to BS7671 for cable sizing
BOILER CONTROL CABLE
0.5mm - 1mm
SUPPORT BACK
OF PCB WHEN
TIGHTENING SCREWS
ENSURE SCREWS
ARE TIGHT.
LOOSE CABLE
CONNECTIONS
CAN CAUSE BURNING
AT THE CONNECTOR
SUPPLY
CONN 5
CONN 1
FS 1 2A 240V
(5 X 20mm)
REMOVE TOP COVER
ONLY TO GAIN ACCESS
TO THE CONNECTIONS
ON THE PRINTED
CIRCUIT BOARD
INSIDE THE BOILER
HOUSING
LIVE EARTH NEUTRAL
LIVE EARTH NEUTRAL RUN NEUTRAL
NL
CONTROL PUMP
CONTROL PUMP
NC N R E N L
NC N R E N L
CASE EARTH
INITIAL TEST SET UP
REMOVE PUMP LIVE AND PUMP
NEUTRAL WIRES FROM CONN1 BLOCK.
RECONNECT PUMP LIVE TO RUN WIRE.
RECONNECT PUMP NEUTRAL TO
NEUTRAL.
UNPLUG CONN1 BLOCK FROM PCB.
ENSURE IT IS SAFE BEFORE CARRYING
OUT TEST.
POWER UP SYSTEM WITH ALL
CONTROLS SET TO RUN.
ENSURE THE BOILER SUPPLY LIGHT IS
ON, CALL LIGHT IS OFF AND PUMP
IS RUNNING.
THIS COMPLETES THE TEST.
SWITCH OFF ALL POWER TO BOILER
AND RECONNECT PUMP NEUTRAL
AND PUMP LIVE WIRES BACK TO
THEIR ORIGINAL POSITIONS.
PLUG THE TERMINAL BLOCK
BACK INTO CONN1 ON THE PCB.
ENSURE CONNECTION SCREWS ARE
TIGHT
22
2 2
Check the full system operates correctly. If at any time the temperature difference between the4.
boiler return and flow is greater that 140C, then there is a flow restriction problem, and must be
rectified immediately. Set pump speed to give 5-100C differential between return and flow on the
boiler when operating at maximum power output.
The pump is operated from the boiler control. It should be connected to the pump terminals on the5.
boiler control board. The pump will run whenever the CALL indicator is illuminated (green) either
flashing or steady, and it will also continue to run if the boiler is hot, even after the demand has
ceased. It will turn off the pump when the boiler temperature falls below approximately 750C. It
will also turn the pump back on if the water temperature rises above 750C again. A bypass must
be incorporated in systems where the heating load can shut down, i.e. when valves or thermostatic
radiator valves are fitted. See note on the bypass (page 5).
The6. ALARM indicator flashing (red) will only illuminate if there is a problem. If there is a water
problem the HEAT and the CALL (green) indicators will turn off. The boiler will remain in this
tripped state until the fault is corrected and the boiler is re-set.
An ALARM indicator flashing (red) together with the CALL indicator (red) indicates an over7.
temperature problem.

18
FIGURE FOURTEEN: OPERATION OF THE C SERIES ISSUE 5 BOILER
MAIN POWER ON
CONTINUE CHECK FOR ALL AS
LONG AS BOILER IS POWERED
RUN TO ON
PUMP ON AND PRE-HEAT ON
THEN WAIT FOR 1 - 1.5 MINUTES
CALL LED RED
ALARM LED FLASHING
IS TEMP
SWITCH OPEN
I.E. FAULTY OR
BOILER OVER
TEMP
DO BOTH
THERMISTOR BEADS
READ SAME VALUE I.E.
TEMPERATURE
CONTINUE CHECK FOR A
FURTHER 2 MINUTES
SWITCH OFF PRE-HEAT, POWER
UP AND MODULATE BOILER
RUN TO OFF
BOILER POWERS DOWN
IS WATER IN
BOILER BELOW
70ºC/75ºC
KEEP PUMP RUNNING
OR PUMP ON
ALARM LED FLASHING
(NO WATER OR INSUFFICIENT
WATER FLOW)
PUMP OFF
YES
NO
NO
YES
NO
YES

19
The SUPPLY indicator (green) will remain illuminated all the time the supply is present to the boiler.
The CALL indicator will illuminate (green) on demand from the programmer and thermostats or (red)
for an alarm overheat condition. It will flash (green) for 2 to 3 minutes during which it carries out
self-tests before allowing the boiler to produce heat. At the end of this period it will remain on steady
(green), until the heating demand is satisfied.
The HEAT indicator will illuminate when the boiler actually
produces heat, this is only when the CALL indicator (green) is
steady. The gradual build up in heating power of the boiler can
be seen on the front panel. The HEAT indicator also shows the
boiler modulating when it reaches operating temperature.
The ALARM indicator flashing (red) will only illuminate if there is
a problem. The HEAT and the CALL (green) indicators will turn
off. The boiler will remain in this tripped state until it is re-set.
To reset an ALARM follow the ‘Alarm Reset’ procedure.
TEMPERATURE CONTROL. The boiler output temperature can be
adjusted from the front panel Minimum setting for C series is
approximately 650C and U series 300C. Maximum setting for C
series is approximately 800C and U series is 600C.
CLEANING. Use only a damp cloth and mild detergent to clean
the boiler outer casing. Do not use abrasive cleaners. Do not
allow water inside the boiler. Do not immerse in water.
OPERATION & INDICATORS
SERVICING
IT IS ESSENTIAL THAT THE BOILER IS CHECKED ANNUALLY, Checks must include the electrical
connections and inhibitor concentration.
Before any servicing or maintenance is carried out on the system, ensure that the electrical supply
has been disconnected first. Care must also be taken as the water may be scalding hot and at a high
pressure.
Check the main electrical power connections are tight. Loose connections can cause a burning at
the connectors.
Part Locations and comments (see page 2)
Fuse FS1 is found near the top of the main power PCB assembly.
The temperature switch connected to Conn 3 is situated on the body of the boiler approximately
1/3rd of the distance up from the bottom between insulation and boiler.
The thermistor assembly plugs into the main power PCB assembly through Conn 4, and is clamped
at the top of the boiler. Care must be taken not to break the fine wires.
The control PCB assembly is mounted on the back of the bottom front panel, and plugged into the
main power PCB Conn 2. Great care must be taken when changing this board assembly not to damage
any of the components, especially those adjacent to the mountings.
To change the main power PCB, follow ‘Replacing the Main Power PCB’ procedure (see page 20).
Each of the main electrical elements should have a resistance of approximately 19 ohms terminal to
terminal, (red to red, yellow to yellow, blue to blue, and black to black) and an insulation resistance
greater than 2 Meg ohms between terminal and case. If the elements are open circuit terminal
to terminal, or have short circuit insulation resistance terminal to case, then the boiler must be
replaced.
FIGURE FIFTEEN: CONTROL PANEL
Gold
Low High
Overheat
Boiler ON
Call
Mains ON

20
Note: Before any maintenance is carried out on the system, ensure that the electrical supply has been
disconnected first. Care must be taken as the water may be scalding hot and at high pressure.
Maintenance on the boiler can only be carried out by a qualified and competent tradesman in
accordance with supplied instructions.
Removal of the Main Power PCB
Switch OFF electrical supplies to the boiler. Both Main, “Live and Neutral”, and Control “R and N”1.
must be isolated
Remove the front top panel.2.
Disconnect the control PCB and carefully remove the high temperature insulation and the front3.
bottom panel.
Unplug the control connector (Conn1), the temperature switch connector (Conn3), and the4.
thermistor connector (Conn4).
Unplug the power connectors on the elements.5.
Disconnect the main power cable to Conn5.6.
Remove the 4 screws identified by the black triangles, see figure sixteen below.7.
Carefully remove the PCB assembly from the pipework. This may be stiff and gentle prising at8.
the top may be required.
Replacing the Main Power PCB
Ensure heat sink compound is used on the heat sinks.1.
Identify and plug the power connectors onto the elements, colour for colour, as it is easier to2.
make these connections before fitting the PCB.
Holding the back plate line up the pillars with the PCB and position it onto the pipework.3.
Loosely add the 4 fixing screws.4.
Tighten up these screws in the order shown below in figure sixteen. It is important to ensure that5.
the PCB assembly is tight on the pipework.
Reconnect connectors (Conn1, 3 & 4)6.
Reconnect the control PCB and replace the high temperature insulation.7.
Ensure the main power connections are tight. Loose connections can cause a fire.8.
REPLACING THE MAIN POWER PCB
12
3
4
FIGURE SIXTEEN: MAIN POWER PCB