Potterton Titanium 12 Heat Quick start guide

Titanium Heat
12 - 15 - 18 - 24 - 30
Condensing Central Heating Boiler
en
United Kingdom
Engineer’s Service Manual

1. Contents
1 Contents 2
2 General Description 3
2.1 Alpha Codes 3
2.2 Main component parts 3
3 Sequence of operation 4
4 Boiler layout 5
5 HMI 6
5.1 L.E.D sequences 6
6 Electrical connections 7
6.1 Wiring diagrams 7
6.2 Boiler electrical diagram 8
6.3 Useful electrical checks 9
6.4 Checking the operational (working)
gas pressure 9
6.5 Measuring the gas rate 9
7 Setting and checking the air/gas ratio 10
7.1 Setting the boiler to full & part load 10
8 Error codes 11
8.1 Shutdowns and lock-outs 11
8.1.1 Blocking 11
8.1.2 Lock out 11
8.1.3 Hard Reset 13
9 Maintenance 14
9.1 General 14
9.2 Standard Inspection & Maintenance
Operation 15
10 Spare parts 17
10.1 General 17
10.2 Spare Parts List 17
11 Notes 18
2

7668920
Code
Number
Alpha
Code
Gas Council
Number
Model
Potterton Titanium 12 Heat RWW 41-592-61
7668922 Potterton Titanium 15 Heat RXE 41-592-62
7668923 Potterton Titanium 18 Heat RXF 41-592-63
7668924 Potterton Titanium 24 Heat RXM 41-592-64
7668925 Potterton Titanium 30 Heat RXX 41-592-65
2.1 Appliance Alpha Codes
Burner
Heat Exchanger
Gas Valve
PCB
Fan
Premix
Aluminium
SIT 848 1:1 ratio
SIT-R
Natalini DC
The Potterton Titanium Heat models use the following component parts:
2.2 Main component parts
1. The Potterton Titanium Heat models are gas fired wall mounted powered flue condensing boilers.
2. The boiler modulates automatically to the system load up to the set output. It is designed for use on Natural Gas
(G20) only.
3. The two illuminated User Interaction Controller push buttons provide information about the operating condition of
the boiler.
4. The boiler is suitable for fully pumped open vented central heating and domestic hot water systems and sealed
systems.
5. An information label giving details of the model, serial number and Gas Council number is situated on the front left
underside of the outer case and is accessed by pulling forward gently.
6. The boiler data label is positioned on the inside lower right-hand side of the boiler and can be seen when the outer
case panel is removed.
7. The boiler is intended to be installed in residential/domestic environments on a governed meter supply only.
8. The boiler is installed with one of the purpose designed flues such as one of the standard telescopic flue kits
detailed in the Flue Accessories & Fitting Guide.
9. All systems must be thoroughly cleansed, flushed and treated with inhibitor.
10. This Engineer’s Manual should be read in conjunction with the Installation & Service Manual supplied in the
Literature Pack.
2. General Description
3

3. Sequence of Operation
Mains ON
(CH or DHWdemand)
Self-test cycle for 20 s
(output setting displayed)
Flow temperature
less than set point
10 second pre purge
5 second ignition
Flame detected
5th ignition attempt
NO
Ignition lockout
Burner ON
Modulate output
Flow temperature or
rate of rise too high
NO
Burner OFF
Over temperature
fault
Lock out
Mains OFF
(demand satisfied)
NO
1. Switched Live On: When the boiler switched live
turns on the boiler, a 20 second check cycle takes
place. If the flow temperature is less than the boiler
set-point temperature the ignition cycle will start.
Pre-purge, Ignition and Burner on.
2. Fan Pre-Purge: The boiler has a 10 second
pre-purge (Fan On, Spark Generator and Gas Valve
off) before the start of the ignition sequence.
3. Ignition: The boiler has a 5 second ignition period
(Fan, Spark Generator and Gas Valve on) and burner
on occurs when a flame is detected. If a flame is not
detected within the 5 second ignition period then 4
more ignition attempts are made. If a flame is not
detected after the 5 ignition attempts the boiler goes
to an ignition lock-out and an error light is displayed.
4. Burner on: After a successful ignition, Burner on
occurs (Fan and Gas Valve on, Spark Generator off).
The boiler flow temperature is controlled by varying
the fan speed (and thereby the gas rate) to achieve
the optimum boiler operation. If the boiler flow
temperature exceeds the boiler set-point, the burner
will turn off (Fan and Gas Valve off).
5. Over temperature: If a boiler over temperature
event occurs (triggering the safety thermostat) the
burner shuts down (Fan off and Gas Valve off). A
locking signal is generated and an error lightis
displayed.6. Lockout: If a lock-out error is displayed
(Fan, Spark Generator and Gas Valve off) the boiler
can only be reset by manually pressing the reset
button. If 5 lock-outs are reset within a 1 hour period
then a hard reset is required see section 8.1.3
Baxi Customer Support 0344 871 1525
4

4. Boiler Layout
Potterton Titanium Heat main components
5
1. Heat Exchanger
2. Combustion Control Unit
3. Condensate Trap
4. Exhaust Tube
5. Inlet Silencer
6. User Interaction Controller
7. Gas Cock
8. Air Pressure Switch (24 & 30 model only)
9. System Drain Cock
10. Air Vent
1
2
3
4
5
67
8
9
10

5.0 HMI
5.1 LED sequences
Boiler in operation
Demand
Blocking
Temperature protection
Blocking input
Flame loss
Communication error
Parameter or id fault
Miscellaneous
Lockout
Sensor error
Max temp protection
Ignition fault
Fan fault
Parameter error
Miscellaneous
Reset
Working with reset
The HMI has 2 illuminating push buttons which provide information about the operating condition of the boiler.
The ‘RESET’ button lights up green when the boiler has a demand.
The ‘Chimney Sweep’ button can flash in a range of colours and at different frequencies.
The HMI also has one rotary knob. The rotary knob can be used to set the maximum flow temperature of the
heating water.
The temperature on this rotary knob must be set to a higher temperature than the cylinder thermostat to
achieve the required hot water demand.
Chimney sweep mode
Minimum
Maximum
Maximum
PCB programming
1 Heating water temperature rotary knob
2 Chimney Sweep button and Status signals
3 RESET-button and on/off signal
6
1 2 3

The boiler is supplied with 1 metre of 3 core cable connect-
ed to the boiler.
Switched live must be connected to the brown (live) wire of
the 3 core cable.
Connecting External Devices:
This boiler operates on a switched live only.
To comply with Part L1 of the Building Regulations the
heating system into which the boiler is installed should
include the following:
a) Zone Controls
b) Timing Controls
c) Boiler Control Interlocks (Room & Cylinder
Thermostats)
Such a system needs to be fully pumped and must provide
independent temperature and time control to both the
heating and hot water circuits.
Connection diagrams for Y and S plan systems are shown
below.
6.1 Wiring Diagrams
‘S’ Plan, Room Thermostat System, CH Interlocked by Room
Thermostat. At least the Radiator(s) near the Room Thermostat
without TRVs. Pump runs from Switched Live.
‘Y’ Plan, Room Thermostat System, CH Interlocked by Room
Thermostat. At least the Radiator(s) near the Room Thermostat
without TRVs. Pump runs from Switched Live.
Key to colours
b Blue br Brown w White
o Orange gr Grey g/y Green & Yellow
Y Plan
Diverter
Valve
Cylinder
Stat
Room
Stat
Boiler
PumpPump
Timer
230V
50Hz
L N E
L
N
CH on
HW on
HW off
LN E
L N P/FE
b
g/y w
o
gr
1
C 2
g/y
S Plan
Valve
Cylinder
Stat
Room
Stat
Boiler
Pump
Timer
230V
50Hz
L N E
L
N
CH on
HW on
LN E
L NE
Motor
S Plan
Valve
Motor
o
o
gr
b
g/y
b
gr
br
br
7
6.0 Electrical Connections
3 Core Cable - 1 metre
supplied connected to boiler

6.2 Boiler Electrical Diagram
Pressure Switch
Titanium Heat 24 & 30 Models only
8
Gas Valve
Electrode
br
br
b
g/y
g/y
r
Electrical
Test Point
Mains
g/y
x1
IT
E
P
1
2
3
x8
c1
c2
x5
br
b
Safety
Thermostat
Return
Sensor
Flow
Sensor
Parameter
Unit
User Interaction
Controller
r
b
Not used
Loop Connector
(where no Pressure
Switch fitted)
Key To Wiring Colours
b - Blue
r - Red
br - Brown
g/y - Green/Yellow
bk - Black
FROM TO COLOUR LINK
PRESSURE SWITCH
PRESSURE SWITCH
COMBI ONLY
COMBI ONLY
COMBI ONLY
FLOW TEMP
FLOW TEMP
RETURN TEMP
RETURN TEMP
FLOW SENSOR
FLOW SENSOR
FLOW SENSOR
HIGH LIMIT BLACK
BLACK
BLACK
BLACK
BLUE
RED
PSU
PSU
PSU
PSU
BLACK
BLACK
BLACK
BLACK
BLACK
BLACK
HIGH LIMIT
1
2
3
4
5
6
7
8
9
10
11
12
13
13 1
23456
7
89
10
11
12
bk
bk
bk
bk
bk
bk bk
bk
bk
1
13
RS232
HMI
HL
TR
TA
PSU
APS
g/y
br
b
LN

6.3. Useful Electrical Checks
RS232
Computer connection
TR
Return sensor
IT
Ignition transformer
TA
Flow sensor
E
Ignition/ionisation electrode
PSU
Storage parameter
P
Power supply
HMI
Connection box
HL
Safety thermostat
APS
Air pressure switch
Plug
Function
Pins
Colours
Voltage
Resistance
X1 Mains
1 – 2
G/Y – Br
240v AC
N/A
1 – 3
G/Y – B
0 -15v AC
N/A
2 – 3
Br – B
240v AC
N/A
X5
Flow Thermistor
7 – 8
Bk – R
12kΩ @ 25°C
Return Thermistor
6 – 7
B – Bk
12kΩ @ 25°C
Safety Thermostat / Air
Pressure Switch
1 – 13 Bk – Bk
Closed circuit under
110°C
X8 Gas Valve
L – N
Br – B
240v AC
780Ω
N – E
B – G/Y
0 -15v AC
N/A
L – E
Br – G/Y
240v AC
N/A
Fan Part Load
C1 – C2
Y – Y
124 – 129v AC
75Ω
Fan Max CH Load
C1 – C2
Y – Y
238 – 243v AC
Fan Max HW Load
C1 – C2
Y – Y
263 – 265v AC
12 1.42
15 1.75
18 2.07
2.73
24
30 3.27
Model m3/hr
6.4. Checking the Operational (Working) Gas Inlet Pressure
Ensure that all controls are calling for heat and maximum load is applied to the system see ‘Chimney Sweep’ mode
(see section 7)
2. With the boiler operating in the maximum rate condition check that the operational (working) gas pressure at the
gas cock in accordance with B.S. 6798 & B.S. 6891.
3. Ensure that the 20mbar inlet pressure can be obtained with all other gas appliances in the property working.
Gas inlet pressure point
6.5. Measuring the gas rate
With any other appliances & pilot lights turned OFF the gas rate can be measured(see chart below).
U6 Gas rate = 100.8÷Time in sec for 1ft³ of gas=________M³/hr
E6 Gas rate = Two minutes of gas x 30=_______M³/hr
9

10
EV1
EV2
P. OUT
1 2 3 4
VENT
RQ ADJ.
P
.
R
.
A
D
J
.
‘A’
Max Rate
Adjustment
Screw
(cover removed)
‘B’
MIN rate
Adjustment
Screw
(cap fitted)
Reduce CO 2
at MIN. rate
Increase CO
Increase CO
2
at MIN. rate
Reduce CO 2
at MAX. rate
2
at MAX. rate
7.0 Setting and checking the air/gas ratio
7.1 Setting the boiler to full load & part load
Use this procedure when Commissioning, Servicing &
Replacing the Gas valve.
The full load status can only be reached via the part load
status.
1. Press the Chimney Sweep button for around 3 seconds.
The status signal for the Chimney Sweep button is orange
and flashes green briefly; Part load is selected.
2. Press the Chimney Sweep button again twice. The
status signal for the Chimney Sweep button is orange and
goes off briefly twice; Full load is selected.
3. Remove the plug of the flue gas measurement point.
4. Insert the probe for the flue gas analyser into the
measurement opening. See Fig for the position of control
screw A for full load adjustment.
5. Check the CO
2
is 9.3% ±0.1% (Case OFF). If the CO
2
is
too low, turn the screw A anticlockwise to increase (2.5mm
Allen key). If the CO
2
is too high, turn the screw A clock-
wise to decrease. Now part load needs to be selected
6. Press the Chimney Sweep button again to return to part
load. The status signal for the Chimney Sweep button is
orange and flashes green briefly; Part load is selected.
See drawing for the position of control screw B for part
load.
7. Check the CO
2
is 8.9% ± 0.1% (Case OFF). If the CO
2
is too high, turn the screw B anticlockwise to reduce (4mm
Allen key). If CO
2
is too low, turn the screw B clockwise to
increase.
8. Briefly press the RESET button to return the boiler to
normal operating status.
9. Remove the probe for the flue gas analyser from the
measurement opening.
10. Refit the plug of the flue gas measurement point.
WARNING!
The full load value must be at least 0.4%
higher than the part load value. If this gap
has not been achieved the values must be
reset.
Plug
Analyser Probe
Flue Sampling
Point
After refitting the sampling
point plug ensure there is
no leakage of products !

1 2 3
1 Heating water temperature rotary knob
2 Chimney Sweep button and Status signals
3 RESET-button and on/off signal
8.0 Error Codes
The status signal for the ‘Chimney Sweep’button can flash in a range of colours and at different frequencies. The
meaning of these signals can be found below.
8.1 Shutdowns and lock-outs
8.1.1 Blocking
A (temporary) blocking mode is a boiler operating function caused by an unusual situation. The boiler control will try to
re-start several times. The boiler will start up again after the blocking conditions have been eliminated. In the event of
a shutdown, the status signal for the ‘Chimney Sweep’ button flashes green. The meaning of the shutdown codes can
be found in the table below.
Status signals Description
Shutdown code 1 (1 times green signal) Temperature protection
Shutdown code 2 (2 times green signal) Blocking input
Shutdown code 3 (3 times green signal) Flame loss
Shutdown code 4 (4 times green signal) Communication error
Shutdown code 5 (5 times green signal) Parameter or identification fault
Shutdown code 6 (6 times green signal) Miscellaneous
Table of blocking signals
Status signals Description
Table of Lock-out Signals
Blocking
Temperature protection
Blocking input
Flame loss
Communication error
Parameter error
Miscellaneous
8.1.2. Lock-out
If the blocking conditions still exist after several start up attempts, the boiler will switch into locking mode (fault). The
boiler will only start operating again once the cause of the lock-out has been rectified and after pressing the RESET
button. In the event of a fault, the status signal for the ‘Chimney Sweep’ button flashes red. The description of the error
code is given in the error table.
Error code 1 (1 times red signal) Sensor error
Error code 2 (2 times red signal) Maximum security
Error code 3 (3 times red signal) Ignition fault
Error code 4 (4 times red signal) Fan fault
Error code 5 (5 times red signal) Parameter error
Error code 6 (6 times red signal) Miscellaneous
11

12
Blocking
Sensor error
Maximum security
Ignition fault
Fan fault
Parameter error
Miscellaneous
Reset
Working to reset
Press the RESET key for 5 seconds: The status signals will flash red quickly and the boiler will start its reset proce-
dure.If the error code continues to display, search for the cause in the error table and apply the solution.
8.1.2 Lock-out (continued)
Lock-out (Status signals)
Status signals Description Probable causes Checking/solution
Error Code 1
(1 x red signal)
Error Code 2
(2 x red signal)
Error Code 3
(3 x red signal)
Error Code 4
(4 x red signal)
Error Code 5
(5 x red signal)
Error Code 6
(6 x red signal)
Fan fault
Parameter
error
Miscellaneous
Ignition fault:
5 burner start-up
failures
False flame
signal
5x Flame loss
Maximum
temperature of
heat exchanger
or control unit
exceeded
Sensor fault,
temperature
fault or flow
fault
Sensor not or badly
connected
Bad connection
Non-existent or
insufficient circulation
Water circulation
direction reversed
Sensor fault
Non-existent or
insufficient circulation
Sensor not or badly
connected
Bad connection
Sensor fault
No air supply or
insufficient air supply
No flue gas flow or
insufficient flue gas
flow
Circulation
Check the wiring.
Check that the sensors are operating correctly
Check that the sensor has been correctly fitted
Vent the air in the heating system
Check the water pressure
Check the cleanliness of the heat exchanger
Check the circulation (direction, pump, valves)
Replace the sensor if necessary
Vent the air in the heating system
Check the water pressure
Check the cleanliness of the heat exchanger
Check the circulation (direction, pump, valves)
Check the wiring
Check that the sensors are operating correctly
Check that the sensor has been correctly fitted
Replace the sensor if necessary
Check air supply
Check flue gas flow
Replace seals
Check the wiring
Check breakdown to earth
Check the condition of the burner set
Check the earthing
Check that the gas valve is fully opened
Check the supply pressure
Purge the gas supply to remove air
Check the operation and setting of the gas valve unit
Check that the air inlet and flue gas discharge flues are not blocked
Replace the ionization/ignition electrode
No ignition
Ignition arc, but no
flame formation
Presence of the flame
but insufficient
ionization (<1μA)
External draught over
the boiler
Defective gas/air unit
Check for adequate draw on the chimney connection
Replace the gas/air unit
Bad connection
Safety parameters not
found
Check the wiring
Several possible
causes
The fault codes can be read with a suitable controller or the service
tool

13
8.1.3 Hard Reset.
Note: a lock-out condition can be re-set up to 5 times within one hour using the reset button. If a more than 5 resets
have been carried out the boiler will require a ‘Hard Reset’. This will be indicated by the ‘Chimney Sweep’ (red) and
‘Reset’ (green) buttons being illuminated.
To perform a ’Hard Reset’ turn the power of to the boiler for 30 seconds.

14
9 Maintenance
9.1 General
WARNING
- When changing components ensure that both the gas and
electrical supplies to the boiler are isolated before any work
is started. Use the electrical test point to confirm safe
isolation.
- When a component has been changed recommission the
boiler as described in the Installation & Service Manual.
The Case Front Panel MUST seal effectively against the
boiler side panels.
- For reasons of safety and economy, it is recommended
that the boiler is serviced annually. Servicing must be
performed by a competent person in accordance with B.S.
7967-4.
- After servicing, complete the relevant Service Interval
Record section of the Benchmark Commissioning Checklist
at the rear of this publication.
- During routine servicing, and after any maintenance or
change of part of the combustion circuit, the following must
be checked:-
- The integrity of the complete flue system and the flue
seals by checking air inlet sample to eliminate the possibili-
ty of recirculation. O2≥ 20.6% & CO2< 0.2%
- The integrity of the boiler combustion circuit and relevant
seals.
- The operational gas inlet pressure and the gas rate.
- The combustion performance as described in ‘Check the
Combustion Performance’ below.
3. Competence to carry out Checking Combustion Perfor-
mance
B.S. 6798 ‘Specification for Installation & Maintenance of
Gas Fired Boilers not exceeding 70kWh’ advises that:-
The person carrying out a combustion measurement should
have been assessed as competent in the use of a flue gas
analyser and the interpretation of the results.
The flue gas analyser used should be one meeting the
requirements of BS7927 or BS-EN50379-3 and be calibrat-
ed in accordance with the analyser manufacturer‘s require-
ments.
Competence can be demonstrated by satisfactory comple-
tion of the CPA1 ACS assessment, which covers the use of
electronic portable combustion gas analysers in accord-
ance with BS 7967, Parts 1 to 4.
Electrical
Test Point

15
9.2 Standard Inspection and Maintenance Operation
Check the Combustion Performance (CO/CO2 ratio)
- Set the boiler to operate at maximum rate as described in
Section 7.
- Remove the plug from the flue sampling point and insert
the analyser probe and obtain the CO/CO2ratio. This must
be less than 0.004. If the combustion reading (CO/CO2
ratio) is greater than this, and the integrity of the complete
flue system and combustion circuit seals has been verified,
and the inlet gas pressure and gas rate are satisfactory the
‘Standard Inspection and Maintenance’ below & re-check.
- Perform ‘Setting the Gas Valve’ (Section 7) & re-check.
- Replace and set the gas valve as described in the Instal-
lation & Service Manual (Sections 10.3.10 & 13) &
re-check.
WARNING
- Ensure that the boiler is cool.
- Ensure that both the gas and electrical supplies to the
boiler are isolated.
- Use the electrical test point to confirm safe isolation.
CAUTION
- Always examine any seals or gaskets, replacing where
necessary. Where a seal or gasket is supplied with a spare
part it should be used, irrespective of the condition of the
original.
- Use only original spare parts that are intended for
use with this type of boiler.
- When performing any inspection or maintenance
personal protective equipment must be used where
appropriate.
- Unscrew the two screws located on the lower front panel.
- Slide the lower front panel forward and hinge down to
remove.
- Unscrew the two securing screws on the front panel.
Remove the front panel.
- Visually check for debris/damage and clean or replace the
following if necessary:
- Check the water pressure (sealed systems)
- Check the flue pipes and air supply pipes for leaks
- Check and clean (if necessary) the condensate trap
- Check the ignition electrode (replace if necessary)
- Check the combustion
- Complete the relevant Service Interval Record section of
the Installation & Service Manual and then hand it back to
the user
- Check and clean the Air Inlet Deflector if necessary.
Plug
Analyser Probe
Flue Sampling
Point
After refitting the sampling
pointplug ensure there is
no leakage ofproducts !
Electrical
Test Point

Gasket
Spark Ignition
Electrode
Earth
Wire
9.2 Standard Inspection and Maintenance Operation (cont.)
Over Centre
Catches
Gasket
Burner
- An ESD wrist strap should be used when working on these
components.
- A T25 screwdriver will be required.
- Remove the air duct by pulling the bottom of the duct forward to
disengage it from the gas valve and then sliding the top of the
duct left away from the fan.
- Disengage the clip at the top of the flue duct, pull the duct
forwards and then manoeuvre it out of the heat exchanger sump
connection.
- Disconnect the cable from the bottom of the PCB, disengage the
fan protective cover securing tab and lower the cover.
- Taking care not to touch the PCB components, disconnect the
electrode lead, earth lead, mains power cable and the main
sensor harness from the board. Re-engage the fan protective
cover.
- Disconnect the plug from the gas valve and undo the nut on the
gas inlet pipe at the base of the valve.
- Remove the gas assembly from the boiler by releasing the
over-centre catches that secure it to the heat exchanger.
- Remove the ignition electrode and check the condition. Replace
if necessary.
- Remove the gasket and burner from the top of the heat exchang-
er. Use a suitable vacuum cleaner to clean the top part of the heat
exchanger.
- The burner does not require any maintenance but must be
checked for cracks or deterioration and replaced if necessary.
CAUTION
- Ensure that all seals and gaskets are in position.
- Ensure that all connectors are refitted to the PCB.
- Reassemble in reverse order and recommission the boiler.
16

10.1 General
1. If, following the annual inspection or maintenance any part of the boiler is found to need replacing, use
Baxi Genuine Parts only.
For a full list of all spare parts for these appliances please see
the Baxi Parts Arena website:
http://interpart.partsarena.eu/
10. Spare Parts - Titanium Heat
10.2 Spare Parts List
B
C
D
E
F
A
17
Sensor Kit
Automatic Air Vent
Ignition/Sensing Electrode
Pressure Switch (24 & 30 only)
Combustion Control Unit 12
Combustion Control Unit 15
Combustion Control Unit 18
Combustion Control Unit 24
Combustion Control Unit 30
User Interaction Controller
7216301
7216300
7216299
7212522
7664628
7664974
7664991
7665026
7665036
7600498
Manufacturer’s
Part No.
Description
Key
Ref
E
A
B
C
D
F

11. Notes
18

11. Notes (continued)
19

e&oe
All descriptions and illustrations provided in this document have been
carefully prepared but we reserve the right to make changes and
improvements in our products which may affect the accuracy of the
information contained in this leaflet. All goods are sold subject to our
standard Conditions of Sale which are available on request.
7676130 01 (01/17)