XSol Diagnostic System

WORCESTER 24 CDI BF

GLOBALLY REPLACED

Next: &20, *

APPLIANCE APPEARS SATISFACTORY

Next: nff

RE-IGNITE DELAY

BOILER ON/OFF SWITCH ON

Next: &nff, !f125

OVERRUN OPERATION

BOILER ON/OFF SWITCH ON

Next: &1, !f124

FLUE

Next: &2, !f92

CH MODULATION

{ISOLATEMAINSPOWER}<

Next: &3, f121

EXCESSIVE SYSTEM PRESSURE RISE

BOILER ON/OFF SWITCH ON
CH TEMPERATURE SELECTOR TO MAXIMUM
ROOM THERMOSTAT (IF FITTED) CALLING

Next: &170, !f120

DHW MODULATION

{ISOLATEMAINSPOWER}<

Next: &5, f111

GAS VALVE SOUNDNESS

Next: &149, !f96

AUTOMATIC FROST PROTECTION

CH TEMPERATURE SELECTOR TO OFF
DHW TEMPERATURE SELECTOR TO MINIMUM
BOILER ON/OFF SWITCH ON

Next: &9, f93

CH BURNER IGNITES

{ISOLATEMAINSPOWER}<

Next: &10, ?82, ?84

DHW HIGH FLAME

{ISOLATEMAINSPOWER}<

Next: &11, f397

DHW LOW FLAME

{ISOLATEMAINSPOWER}<

Next: &12, f450

DHW BURNER IGNITES

{ISOLATEMAINSPOWER}<

Next: &138, ?51, ?53, ?55, ?57

DHW PUMP RUNS

Next: &15, f33

DHW DEMAND

{ISOLATEMAINSPOWER}
REMOVE PLASTIC COVER FROM DIVERTER VALVE MICROSWITCH

Next: &16, f30

DHW FLOW RATE

Next: &17, f429

SYSTEM CHECKS

{ISOLATEMAINSPOWER}

Next: &351, !f22

WORCESTER 24 CDI BF

{ISOLATEMAINSPOWER}<

Next: &19, !f21

DHW BURNER ESTABLISHED (FLAME SENSE)

Next: &13, f139

DHW OPERATION

DHW TEMPERATURE SELECTOR TO MAXIMUM

Next: &7, ?150, ?154, ?199, ?367

CENTRAL HEATING OPERATION

BOILER ON/OFF SWITCH ON
ROOM THERMOSTAT (IF FITTED) CALLING

Next: &4, ?171, ?173, ?385

FAIL POINT A

OUTSIDE MODEL

Next: &nff, f210

FAIL POINT B

OUTSIDE MODEL

Next: &nff, f216

FAIL POINT C

OUTSIDE MODEL

Next: &nff, f222

FAIL POINT D

OUTSIDE MODEL

Next: &nff, f226

FAIL POINT E

OUTSIDE MODEL

Next: &nff, f234

FAIL POINT F

OUTSIDE MODEL

Next: &nff, f248

FAIL POINT G

OUTSIDE MODEL

Next: &nff, f254

FAIL POINT H - LINK TO DHW BURNER IGNITES

OUTSIDE MODEL

Next: &nff, !f295

FAIL POINT I

OUTSIDE MODEL

Next: &nff, f297

FAIL POINT J

OUTSIDE MODEL

Next: &nff, f355

FAIL POINT K

OUTSIDE MODEL

Next: &nff, f348

TYPE OF DIAGNOSTIC PROCEDURE

PLEASE SELECT FROM O

Next: &353, !f352

FAULT CODES

Next: &18, !f354

FUSE INVESTIGATION TREE

OUTSIDE MODEL

Next: &nff, f481

DHW MODULATION

THERMISTOR SENSOR

Next: End

EXPANSION VESSEL

Next: End

CH MODULATION

PRIMARY SENSOR

Next: End

OVERRUN OPERATION

PCB - BOSCH HEATRONIC

Next: End

RE-IGNITION DELAY

PCB - BOSCH HEATRONIC

Next: End

NO GAS PRESSURE, NO SPARKING PRESENT

DIVERTER VALVE SWITCH ASSEMBLY

Next: End

NO GAS PRESSURE, NO SPARKING PRESENT

THERMISTOR SENSOR

Next: End

NO GAS PRESSURE, NO SPARKING PRESENT

PRIMARY SENSOR

Next: End

10K RESISTOR

HARNESS - MAIN

Next: End

DHW BURNER IGNITES

PCB - BOSCH HEATRONIC

Next: End

BURNER NOT ESTABLISHING

GAS INLET PRESSURE

Next: End

MINIMUM GAS PRESSURE

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

CH NOISY

PUMP C/W LEAD - CIRCULATING - GRUNDFOS

Next: End

BOILER NOISY

PRIMARY SENSOR

Next: End

CH OP NOISY

HEAT EXCHANGER - GAS TO WATER - INTER ALBION

Next: End

RADS DO NOT HEAT

ISOLATING VALVE 22MM

Next: End

RADS DO NOT HEAT

PUMP C/W LEAD - CIRCULATING - GRUNDFOS

Next: End

CH RADS COLD

DIVERTER VALVE ASSEMBLY - INTER ALBION

Next: End

DHW NOISY

HEAT EXCHANGER - GAS TO WATER - INTER ALBION

Next: End

DHW NOISY

PUMP C/W LEAD - CIRCULATING - GRUNDFOS

Next: End

DHW NOISY

THERMISTOR SENSOR

Next: End

DHW RUNS HOT AND COLD DHW MODULATION

THERMISTOR SENSOR

Next: End

DHW HOT AND COLD

HEAT EXCHANGER - GAS TO WATER - INTER ALBION

Next: End

DHW COOL RADS COOL

PUMP C/W LEAD - CIRCULATING - GRUNDFOS

Next: End

ELECTRICAL CHECKS

Next: End

FAIL POINT A

FUSE 2 AMP

Next: End

FAIL POINT A

Next: End

FAIL POINT B

FUSE 1.25 AMP

Next: End

SYSTEM CHECKS

Next: End

FAIL POINT B

TRANSFORMER - JUNKER

Next: End

FAIL POINT C

PCB - BOSCH HEATRONIC

Next: End

FAIL POINT D

Next: End

FAIL POINT D - NEON FAULTY

PCB - BOSCH HEATRONIC

Next: End

FAIL POINT E

KIT - DIAPHRAGM - REPLACEMENT

Next: End

FAIL POINT E

DIVERTER VALVE SWITCH ASSEMBLY

Next: End

FAIL POINT E - NEON FAULTY

PCB - BOSCH HEATRONIC

Next: End

FAIL POINT F

FROST PROTECTION

Next: End

FAIL POINT F

PRIMARY SENSOR (AUTO FROST)

Next: End

FAIL POINT G - NO POWER TO PUMP

PCB - BOSCH HEATRONIC

Next: End

FAIL POINT G - RUNNING SLOW

PUMP C/W LEAD - CIRCULATING - GRUNDFOS

Next: End

FAIL POINT G

GAS INLET PRESSURE

Next: End

FAIL POINT G - BOSCH GV

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

FAIL POINT G - DUNGS GV

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

FAIL POINT G

PCB ADJUSTMENT

Next: End

FAIL POINT G

HEAT EXCHANGER - GAS TO WATER - INTER ALBION

Next: End

FAIL POINT G

PLATE HEAT EXCHANGER - INTER ALBION

Next: End

FAIL POINT G

PRIMARY SENSOR

Next: End

FAIL POINT G - NO PUMP OVERRUN

PCB - BOSCH HEATRONIC

Next: End

FAIL POINT H

Z REDIRECT

Next: End

DIVERTER VALVE (DIAPHRAGM)

KIT - DIAPHRAGM - REPLACEMENT

Next: End

FAIL POINT K

Z REDIRECT

Next: End

TYPE OF DIAGNOSTIC PROCEDURE

Z REDIRECT

Next: End

FAULT CODES

Z REDIRECT

Next: End

FAIL POINT J10K RESISTOR

HARNESS - MAIN

Next: End

DHW COOL

PUMP C/W LEAD - CIRCULATING - GRUNDFOS

Next: End

DHW TOO COOL

HEAT EXCHANGER - GAS TO WATER - INTER ALBION

Next: End

DHW COOL RADS COOL

THERMISTOR SENSOR

Next: End

DHW COOL RADS COOL

PRIMARY SENSOR

Next: End

CH OPERATION SHUTTING DOWN EARLY

PRIMARY SENSOR

Next: End

DHW HIGH FLAME

GAS INLET PRESSURE

Next: End

DHW HIGH FLAME RESISTANCE

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

PCB (24 VOLT SUPPLY)

PCB - BOSCH HEATRONIC

Next: End

DHW BURNER IGNITES

GAS INLET PRESSURE

Next: End

ROOM THERMOSTAT/EXTERNAL CONTROLS

Next: End

DHW FLOW ADJUSTER

Next: End

TRANSFORMER

TRANSFORMER - JUNKER

Next: End

DHW INLET FILTER

FILTER STAINLESS STEEL

Next: End

FLOW RESTRICTOR

FLOW REGULATOR

Next: End

DHW FLOW RATE

MAINS WATER SUPPLY

Next: End

DHW BURNER ESTABLISHES - LEAD DAMAGED

PROBE - FLAME SENSOR C/W LEAD

Next: End

FLAME SENSE ELECTRODE

HARNESS MAIN

Next: End

DHW LOW FLAME

GAS INLET PRESSURE

Next: End

DHW LOW FLAME - BOSCH GV

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

DHW LOW FLAME - DUNGS GV

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

HIGH FLAME - BOSCH GV

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

HIGH FLAME - DUNGS GV

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

DHW PUMP RUNS

FUSE 1.25 AMP

Next: End

DHW PUMP RUNS

FUSE 2 AMP

Next: End

DHW PUMP RUNS

MAINS FUSE

Next: End

DIVERTER VALVE MICROSWITCH

DIVERTER VALVE SWITCH ASSEMBLY

Next: End

FUSE INVESTIGATION

PUMP C/W LEAD - CIRCULATING - GRUNDFOS

Next: End

FUSE INVESTIGATION - MAIN

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

FUSE INVESTIGATION - MODUREG

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

FAIL POINT I

PRIMARY SENSOR

Next: End

FAIL POINT I

THERMISTOR SENSOR

Next: End

FAULT CODE G

THERMOSTAT - OVERHEAT - ELMWOOD

Next: End

PCB (IGNITION TRANSFORMER)

PCB - BOSCH HEATRONIC

Next: End

SPARK ELECTRODES

SPARK ELECTRODE ASSEMBLY

Next: End

DHW BURNER IGNITES

SPARK ELECTRODE ASSEMBLY

Next: End

OVERHEAT THERMOSTAT

THERMOSTAT - OVERHEAT - ELMWOOD

Next: End

GAS VALVE (SOLENOIDS)

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

PRIMARY SENSOR

Next: End

FLUE

Next: End

PRIMARY SENSOR (AUTO FROST)

Next: End

GAS VALVE SOUNDNESS

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

DHW MODULATION

PCB - BOSCH HEATRONIC

Next: End

CH MODULATION

PCB - BOSCH HEATRONIC

Next: End

PCB (LOCKOUT RESET STATUS)

Next: End

DIVERTER VALVE

DIVERTER VALVE ASSEMBLY - INTER ALBION

Next: End

CH OP NOISY

Next: End

RADS DO NOT HEAT

Next: End

DHW OPERATION NOISY

PLATE HEAT EXCHANGER - INTER ALBION

Next: End

DHW RUNS HOT AND COLDDHW MODULATION

PCB - BOSCH HEATRONIC

Next: End

DHW OPERATION HOT AND COLD

PLATE HEAT EXCHANGER - INTER ALBION

Next: End

FAIL POINT A

PCB - BOSCH HEATRONIC

Next: End

FAIL POINT B

PCB - BOSCH HEATRONIC

Next: End

FAIL POINT C

Z REDIRECT

Next: End

FAIL POINT D - IGNORING CH DEMAND

PCB - BOSCH HEATRONIC

Next: End

FAIL POINT D

Z REDIRECT

Next: End

FAIL POINT E

DIVERTER VALVE (SPINDLE)

Next: End

FAIL POINT E

PCB - BOSCH HEATRONIC

Next: End

FAIL POINT E

Z REDIRECT

Next: End

FAIL POINT F

PCB - BOSCH HEATRONIC

Next: End

FAIL POINT G

PRESSURE GAUGE

Next: End

FAIL POINT G

SYSTEM PRESSURE

Next: End

FAIL POINT G - NOT RUNNING

PUMP C/W LEAD - CIRCULATING - GRUNDFOS

Next: End

FAIL POINT G - BOSCH GV

GAS VALVE ADJUSTMENT

Next: End

FAIL POINT G - DUNGS GV

GAS VALVE ADJUSTMENT

Next: End

FAIL POINT G

Next: End

FAIL POINT G

THERMOSTAT - OVERHEAT - ELMWOOD

Next: End

FAIL POINT G - NOT SHUTTING DOWN

PCB - BOSCH HEATRONIC

Next: End

NO FAULT FOUND

OVERHEAT

Next: End

FAIL POINT I

PCB - BOSCH HEATRONIC

Next: End

DIVERTER VALVE (SPINDLE)

Next: End

FAIL POINT K

PCB - BOSCH HEATRONIC

Next: End

FAIL POINT J

PCB - BOSCH HEATRONIC

Next: End

DHW COOL RADIATORS COOL

PLATE HEAT EXCHANGER - INTER ALBION

Next: End

DHW TOO COOL

PCB - BOSCH HEATRONIC

Next: End

DHW TOO COOL RADS COLD

INJECTOR NO7 4.5MM - MAIN BURNER - NG

Next: End

DHW TOO COOL RADS COLD

BURNER - AEROMATIC

Next: End

CH OPERATION SHUTTING DOWN EARLY

PCB - BOSCH HEATRONIC

Next: End

GAS VALVE

GAS VALVE - MULTIFUNCTION - DUNGS

Next: End

CH BURNER IGNITES

PCB - BOSCH HEATRONIC

Next: End

SECONDARY HEAT EXCHANGER (SCALED)

PLATE HEAT EXCHANGER - INTER ALBION

Next: End

DHW BURNER ESTABLISHED (FLAME SENSE)

PCB - BOSCH HEATRONIC

Next: End

PCB

PCB - BOSCH HEATRONIC

Next: End

DHW LOW FLAME - BOSCH GV

GAS VALVE ADJUSTMENT

Next: End

DHW LOW FLAME - DUNGS GV

GAS VALVE ADJUSTMENT

Next: End

HIGH FLAMED - BOSCH GV

GAS VALVE ADJUSTMENT

Next: End

HIGH FLAMED - DUNGS GV

GAS VALVE ADJUSTMENT

Next: End

DHW PUMP RUNS - F2

Z REDIRECT

Next: End

PUMP

PUMP C/W LEAD - CIRCULATING - GRUNDFOS

Next: End

DHW PUMP RUNS - F1

Z REDIRECT

Next: End

ON / OFF SWITCH

PCB - BOSCH HEATRONIC

Next: End

DHW PUMP RUNS

Next: End

DHW PUMP RUNS - MAINS

Z REDIRECT

Next: End

PCB

PCB - BOSCH HEATRONIC

Next: End

FUSE INVESTIGATION

PCB - FUSE INVESTIGATION

Next: End

FAIL POINT I - PRIMARY SENSOR

HARNESS MAIN

Next: End

FAIL POINT I - DHW SENSOR

HARNESS MAIN

Next: End

SPARK ELECTRODE LEADS

HARNESS ASSEMBLY - IGNITION

Next: End

BURNER INJECTOR

INJECTOR NO7 4.5MM - MAIN BURNER - NG

Next: End

CH BURNER IGNITES

DIVERTER VALVE SWITCH ASSEMBLY

Next: End

PCB (AUTO FROST SENSOR)

PCB - BOSCH HEATRONIC

Next: End

DHW NOISY

CHARACTERISTIC TEST FROM DHW OPERATION

Next: p187

TEMPERATURE RISE BELOW SPECIFICATION, RADIATORS WARM

CHARACTERISTIC TEST FROM DHW OPERATION

Next: !p155

BOILER REACHES TEMPERATURE, RADS DO NOT HEAT

CHARACTERISTIC TEST FROM CH OPERATION

Next: p172

BOILER NOISY

CHARACTERISTIC TEST FROM CH OPERATION

Next: p174

DHW RUNS HOT AND COLD

CHARACTERISTIC TEST FROM DHW OPERATION

Next: p200

PRESSURE READS CORRECTLY BUT DOES NOT INCREASE

CHARACTERISTIC TEST FROM INSPECTION PRESSURE SYSTEM

Next: !p257

SYSTEM PRESSURE LOW

CHARACTERISTIC TEST FROM INSPECTION PRESSURE SYSTEM

Next: !p259

RETURNS TO OVERHEAT FAULT CODE BEFORE 82°C

CHARACTERISTIC TEST FROM OBSERVATION RUN BOILER UP TO TEMPERATURE

Next: !p287

FLOW TEMPERATURE ABOVE 82°C AND BOILER DOES NOT SHUT DOWN

CHARACTERISTIC TEST FROM OBSERVATION RUN BOILER UP TO TEMPERATURE

Next: p289

DHW TOO COOL, RADIATORS COLD

CHARACTERISTIC TEST FROM DHW OPERATION

Next: p368

BURNER INJECTOR BLOCKED OR DAMAGED

CHARACTERISTIC TEST FROM INSPECTION BURNER AND INJECTOR

Next: !p382

BURNER BLOCKED OR DAMAGED

CHARACTERISTIC TEST FROM INSPECTION BURNER AND INJECTOR

Next: !p384

SYSTEM BEGINS TO HEAT BUT BOILER SHUTS DOWN BEFORE REACHING TEMPERATURE

CHARACTERISTIC TEST FROM CH OPERATION

Next: p386

GAS PRESSURE PRESENT, NO SPARKING

CHARACTERISTIC TEST FROM DHW BURNER IGNITES

Next: p52

GAS PRESSURE AND SPARKING PRESENT BUT NO IGNITION

CHARACTERISTIC TEST FROM DHW BURNER IGNITES

Next: p54

NO GAS PRESSURE, NO SPARKING PRESENT

CHARACTERISTIC TEST FROM DHW BURNER IGNITES

Next: p56

SPARKING BUT NO GAS PRESSURE

CHARACTERISTIC TEST FROM DHW BURNER IGNITES

Next: p58

BURNER IGNITES AT HIGH FLAME

CHARACTERISTIC TEST FROM CH BURNER IGNITES

Next: !p83

BURNER DOES NOT IGNITE OR IGNITES BUT DOES NOT RAMP UP

CHARACTERISTIC TEST FROM CH BURNER IGNITES

Next: p85

14/05/2019 08:39:12 1905_1_50_1 01/07/2019 10:09:04

10/06/2019 15:42:24

Next: End

DHW SENSOR MODULATION RESISTANCE

{ISOLATEMAINSPOWER}
DISCONNECT YELLOW WIRES FROM DHW SENSOR

Next: !p113, !f112

PRIMARY SENSOR (CH MODULATION)

{ISOLATEMAINSPOWER}
REMOVE RED WIRES FROM CH SENSOR

Next: !p123, !f122

PRESSURE GAS INLET

{ISOLATEMAINSPOWER}<

Next: p140, !f141

DHW SENSOR MODULATION RESISTANCE

{ISOLATEMAINSPOWER}
DISCONNECT YELLOW WIRES FROM DHW SENSOR

Next: !p204, !f205

FUSE F1 (2 AMP) (FAULT CODE)

{ISOLATEMAINSPOWER}
REMOVE FUSE F1 FROM PCB

Next: p211, !f212

FUSE F2 (1.25 AMP) (FAULT CODE)

{ISOLATEMAINSPOWER}
REMOVE FUSE F2 FROM PCB

Next: p217, !f218

INFORMATION FAIL POINT C

Next: !p223, !f224

OBSERVATION DOES BOILER RESPOND TO CH DEMAND

Next: p227, f228

ROOM THERMOSTAT/EXTERNAL CONTROLS RESISTANCE

{ISOLATEMAINSPOWER}
ROOM THERMOSTAT (IF FITTED) CALLING

Next: !p229, !f230

OBSERVATION DOES BOILER RESPOND TO DHW DEMAND

Next: p235, f236

DHW DEMAND

{ISOLATEMAINSPOWER}
REMOVE PLASTIC COVER FROM DIVERTER VALVE MICROSWITCH

Next: p237, f238

DIVERTER VALVE DIAPHRAGM

{ISOLATEMAINSPOWER}
WATER OFF
DRAIN AND DISCHARGE BOILER

Next: !p239, !f240

TEMPERATURE AMBIENT

{ISOLATEMAINSPOWER}

Next: p249, !f250

INSPECTION PRESSURE SYSTEM

Next: p509, ?256, ?258

PUMP VOLTAGE

Next: !p262, !f263

PRESSURE GAS INLET

{ISOLATEMAINSPOWER}<

Next: p268, !f269

ADJUSTMENT PRESSURE MAX AND MIN (BOSCH)

{ISOLATEMAINSPOWER}<

Next: !p272, !f273

DIFFERENTIAL PLATE HEAT EX

{ISOLATEMAINSPOWER}
ATTACH TEMPERATURE CLAMPS TO PRIMARY FLOW AND RETURN AS INDICATED

Next: !p280, !f281

RESISTANCE PRIMARY SENSOR AT PCB (FAULT CODE)

{ISOLATEMAINSPOWER}
DISCONNECT PLUG CONNECTOR (MARKED ST16) FROM PCB

Next: p298, f503

DIVERTER VALVE DIAPHRAGM

{ISOLATEMAINSPOWER}
WATER OFF
DRAIN AND DISCHARGE BOILER

Next: !p32, !f31

ON/OFF SWITCH VOLTAGE (OUTPUT)

BOILER ON/OFF SWITCH ON

Next: p35, f469

INFORMATION FAIL POINT K

{ISOLATEMAINSPOWER}<

Next: !p349, !f350

10K RESISTOR FAULT CODE

{ISOLATEMAINSPOWER}
DISCONNECT CONNECTOR MARKED ST16 FROM PCB

Next: !p366, !f357

DIFFERENTIAL PRIMARY HEAT EXCHANGER

{ISOLATEMAINSPOWER}
ATTACH TEMPERATURE CLAMPS TO PRIMARY FLOW AND RETURN AS INDICATED

Next: !p373, !f374

PRESSURE GAS INLET

{ISOLATEMAINSPOWER}<

Next: p409, !f408

FUSE F2 (1.25 AMP)

{ISOLATEMAINSPOWER}
REMOVE FUSE F2 FROM PCB

Next: p43, f466

OBSERVATION COLD MAINS FLOW RATE

Next: p437, !f444

PRESSURE GAS INLET

{ISOLATEMAINSPOWER}<

Next: p451, !f452

ADJUSTMENT PRESSURE MAX AND MIN (BOSCH)

{ISOLATEMAINSPOWER}<

Next: !p455, !f456

DIVERTER VALVE MICROSWITCH RESISTANCE

{ISOLATEMAINSPOWER}
DISCONNECT PLUG CONNECTOR (MARKED ST16) FROM PCB

Next: !p49, !f48

ADJUSTMENT PRESSURE MAX AND MIN (BOSCH)

{ISOLATEMAINSPOWER}<

Next: !p462, !f463

FUSE FURTHER INVESTIGATION

Next: !p467, !f468

FUSE F1 (2 AMP)

{ISOLATEMAINSPOWER}
REMOVE FUSE F1 FROM PCB

Next: p470, f471

FUSE FURTHER INVESTIGATION

Next: !p472, !f473

RESISTANCE MAINS FUSE

{ISOLATEMAINSPOWER}
REMOVE THE FUSE FROM THE FUSED SPUR

Next: !p476, f477

FUSE FURTHER INVESTIGATION

Next: !p478, !f479

RESISTANCE PUMP AND HARNESS (FUSE INVESTIGATION)

{ISOLATEMAINSPOWER}
DISCONNECT PLUG ST15 FROM THE PCB

Next: p498, !f483

PRIMARY SENSOR FAULT CODE

{ISOLATEMAINSPOWER}
REMOVE RED WIRES FROM CH TEMPERATURE SENSOR

Next: !p504, !f505

DHW SENSOR (CALLING)

{ISOLATEMAINSPOWER}
DISCONNECT YELLOW WIRES FROM DHW SENSOR
ENSURE DHW IS COOL

Next: !p507, !f508

PRIMARY SENSOR (AUTO FROST)

{ISOLATEMAINSPOWER}
DISCONNECT RED LEADS FROM SENSOR

Next: !p95, !f94

10K RESISTOR

{ISOLATEMAINSPOWER}
DISCONNECT CONNECTOR MARKED ST16 FROM PCB

Next: p129, !f136

PRIMARY SENSOR (CH CALLING)

{ISOLATEMAINSPOWER}
REMOVE RED WIRES FROM CH TEMPERATURE SENSOR

Next: p130, !f135

DHW SENSOR (CALLING)

{ISOLATEMAINSPOWER}
DISCONNECT YELLOW WIRES FROM DHW SENSOR
ENSURE DHW IS COOL

Next: p131, !f134

DIVERTER VALVE MICROSWITCH (RESISTANCE)

{ISOLATEMAINSPOWER}
DISCONNECT PLUG CONNECTOR (MARKED ST16) FROM PCB

Next: !p132, !f133

PRESSURE GAS IGNITION

{ISOLATEMAINSPOWER}<

Next: p445, !f143

INSPECTION ISOLATION VALVES FLOW AND RETURN

{ISOLATEMAINSPOWER}

Next: p181, !f182

PUMP LIMPET TEST

Next: p175, !f176

RESISTANCE PRIMARY SENSOR

{ISOLATEMAINSPOWER}
REMOVE YELLOW WIRES FROM DHW SENSOR

Next: p177, !f178

TEMPERATURE DIFFERENTIAL CH

{ISOLATEMAINSPOWER}<

Next: !p179, !f180

PUMP LIMPET TEST

Next: p183, !f184

CH DIVERTER CHECK

ENSURE SECONDARY HEA

Next: !p185, !f186

PUMP LIMPET TEST

Next: p194, !f193

CENTRAL HEATING OPERATION

BOILER ON/OFF SWITCH ON
ROOM THERMOSTAT (IF FITTED) CALLING

Next: !p191, !f192

RESISTANCE DHW SENSOR

{ISOLATEMAINSPOWER}
REMOVE YELLOW WIRES FROM DHW SENSOR

Next: p190, !f198

PUMP LIMPET TEST

Next: p201, !f208

DHW MODULATION

{ISOLATEMAINSPOWER}<

Next: p202, f203

TEMPERATURE DIFFERENTIAL CH

{ISOLATEMAINSPOWER}<

Next: !p206, !f207

MAINS POWER

BOILER ON/OFF SWITCH ON

Next: !p213, !f214

TRANSFORMER RESISTANCE

{ISOLATEMAINSPOWER}<

Next: !p219, !f220

INFORMATION FAIL POINT D

Next: !p231, !f232

INFORMATION FAIL POINT E

Next: !p245, !f246

DIVERTER VALVE MICROSWITCH RESISTANCE

{ISOLATEMAINSPOWER}
DISCONNECT PLUG CONNECTOR (MARKED ST16) FROM PCB

Next: !p241, !f242

PRIMARY SENSOR (CH HIGH FLAME)

{ISOLATEMAINSPOWER}
REMOVE RED WIRES FROM CH SENSOR

Next: !p251, !f252

DHW PUMP RUNS

Next: p260, f261

PUMP LIMPET TEST

Next: p264, !f265

PRESSURE BURNER MAX AND MIN

{ISOLATEMAINSPOWER}<

Next: p266, f267

PRESSURE BURNER CH MODE

{ISOLATEMAINSPOWER}<

Next: p276, !f277

OBSERVATION GAS VALVE TYPE

THE GAS VALVE WILL N

Next: p270, f271

ADJUSTMENT PRESSURE MAX AND MIN (DUNGS)

{ISOLATEMAINSPOWER}<

Next: !p274, !f275

DIFFERENTIAL PRIMARY HEAT EXCHANGER

{ISOLATEMAINSPOWER}
ATTACH TEMPERATURE CLAMPS TO PRIMARY FLOW AND RETURN AS INDICATED

Next: p278, f279

DIFFERENTIAL PLATE HEAT EX

{ISOLATEMAINSPOWER}
ATTACH TEMPERATURE CLAMPS TO PRIMARY FLOW AND RETURN AS INDICATED

Next: p282, !f283

OBSERVATION RUN BOILER UP TO TEMPERATURE

{ISOLATEMAINSPOWER}<

Next: p284, ?286, ?288

OVERRUN OPERATION

BOILER ON/OFF SWITCH ON

Next: !p292, !f293

PRIMARY SENSOR (CH HIGH FLAME)

{ISOLATEMAINSPOWER}
REMOVE RED WIRES FROM CH SENSOR

Next: !p290, !f291

RESISTANCE DHW SENSOR AT PCB

{ISOLATEMAINSPOWER}
DISCONNECT PLUG CONNECTOR (MARKED ST16) FROM PCB

Next: !p302, f506

TRANSFORMER VOLTAGE (OUTPUT)

BOILER ON/OFF SWITCH ON

Next: p41, f40

PUMP LIMPET TEST

Next: p369, !f370

DIFFERENTIAL PLATE HEAT EX

{ISOLATEMAINSPOWER}
ATTACH TEMPERATURE CLAMPS TO PRIMARY FLOW AND RETURN AS INDICATED

Next: p371, f372

RESISTANCE DHW SENSOR

{ISOLATEMAINSPOWER}
REMOVE YELLOW WIRES FROM DHW SENSOR

Next: p375, !f376

PRIMARY SENSOR (CH HIGH FLAME)

{ISOLATEMAINSPOWER}
REMOVE RED WIRES FROM CH SENSOR

Next: p377, !f378

INSPECTION BURNER AND INJECTOR

{ISOLATEMAINSPOWER}
REMOVE THE BURNER ASSEMBLY FROM THE BOILER

Next: !p379, ?381, ?383

PRIMARY SENSOR (CH HIGH FLAME)

{ISOLATEMAINSPOWER}
REMOVE RED WIRES FROM CH SENSOR

Next: !p387, !f388

FULL VOLTAGE MODULATING SOLENOID

{ISOLATEMAINSPOWER}<

Next: p459, !f417

RESISTANCE GAS VALVE MODULATING SOLENOID

{ISOLATEMAINSPOWER}
DISCONNECT PLUG CONNECTOR (MARKED ST16) FROM PCB

Next: p403, !f415

PUMP VOLTAGE

Next: !p47, f46

PRESSURE GAS INLET

{ISOLATEMAINSPOWER}<

Next: !p424, !f425

ROOM THERMOSTAT/EXTERNAL CONTROLS RESISTANCE

{ISOLATEMAINSPOWER}
ROOM THERMOSTAT (IF FITTED) CALLING

Next: !p427, !f428

TRANSFORMER RESISTANCE

{ISOLATEMAINSPOWER}<

Next: !p45, !f44

DHW FLOW RATE ADJUSTER

{ISOLATEMAINSPOWER}

Next: p438, !f439

DHW INLET FILTER

{ISOLATEMAINSPOWER}
WATER OFF
BOILER DRAINED AND DISCHARGED

Next: p440, !f441

FLOW RESTRICTOR

{ISOLATEMAINSPOWER}
WATER OFF
BOILER DRAINED AND DISCHARGED

Next: !p442, !f443

RESISTANCE FLAME SENSE ELECTRODE

{ISOLATEMAINSPOWER}

Next: p446, !f447

RESISTANCE FLAME SENSE LEAD

{ISOLATEMAINSPOWER}<

Next: !p448, !f449

OBSERVATION GAS VALVE TYPE

THE GAS VALVE WILL N

Next: p453, f454

ADJUSTMENT PRESSURE MAX AND MIN (DUNGS)

{ISOLATEMAINSPOWER}<

Next: !p457, !f458

OBSERVATION GAS VALVE TYPE

THE GAS VALVE WILL N

Next: p460, f461

ADJUSTMENT PRESSURE MAX AND MIN (DUNGS)

{ISOLATEMAINSPOWER}<

Next: !p464, !f465

MAINS POWER

BOILER ON/OFF SWITCH ON

Next: !p474, f475

MAIN GAS VALVE SOLENOID RESISTANCE (FUSE INVESTIGATION)

{ISOLATEMAINSPOWER}
DISCONNECT PLUG CONNECTOR (MARKED ST16) FROM PCB

Next: p499, !f500

RESISTANCE GAS VALVE MODULATING SOLENOID (FUSE INVESTIGATION)

{ISOLATEMAINSPOWER}
DISCONNECT PLUG CONNECTOR (MARKED ST16) FROM PCB

Next: !p501, !f502

OVERHEAT THERMOSTAT RESISTANCE - FAULT CODE

{ISOLATEMAINSPOWER}
DISCONNECT ORANGE WIRES FROM OVERHEAT THERMOSTAT
ENSURE BOILER IS COOL

Next: p255, !f545

IGNITION TRANSFORMER (OPERATION)

{ISOLATEMAINSPOWER}
DISCONNECT ELECTRODE LEADS FROM ELECTRODES AND MAKE SAFE

Next: p60, !f59

SPARK ELECTRODES

{ISOLATEMAINSPOWER}

Next: !p64, !f63

OVERHEAT THERMOSTAT RESISTANCE

{ISOLATEMAINSPOWER}
DISCONNECT ORANGE WIRES FROM OVERHEAT THERMOSTAT

Next: p128, !f65

MAIN GAS VALVE SOLENOID RESISTANCE

{ISOLATEMAINSPOWER}
DISCONNECT PLUG CONNECTOR (MARKED ST16) FROM PCB

Next: p68, !f67

SPARK ELECTRODES

{ISOLATEMAINSPOWER}

Next: !p62, !f61

MAIN GAS VALVE VOLTAGE

{ISOLATEMAINSPOWER}<

Next: p423, !f137

PRIMARY SENSOR (CH HIGH FLAME)

{ISOLATEMAINSPOWER}
REMOVE RED WIRES FROM CH SENSOR

Next: p426, !f86

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