Fault Finder

75 articles

• AFDD Nuisance Tripping: Arc Detection Principle, Dimmer and Motor Load Compatibility, Half-Split Isolation and Bypass Test
  Arc detection principle (series arc 10–999 Hz), dimmer and motor load false-trigger threshold, half-split circuit isolation, manufacturer bypass test procedure
• Air Source Heat Pump Fault Finding: E Codes, Low COP and Defrost Cycle Issues
  ASHP fault finding: low COP (flow temp too high — every 1°C reduction = 2.5–3% COP gain), defrost cycle >20% runtime indicates fault, F-Gas Regulation refrigerant handling restriction, Daikin/Mitsubishi/Vaillant error code overview
• Alpha Boiler Error Codes: Common Faults & Reset Procedures
  Alpha E-Tec error codes: E28 ignition failure, E10 low pressure, E31 overheat, E9 fan fault, E11 APS — condensate freeze the most common winter lockout cause
• Ariston Boiler Error Codes: Common Faults & Reset Procedures
  Ariston Clas One/Alteas error codes: A01 ignition failure, C6 fan fault, F56 low pressure, F65 overheating with reset procedures
• Banging, Clicking or Ticking Pipes: Diagnosing Expansion Noise, Water Hammer and Loose Clips
• Baxi Boiler Error Codes: Complete Diagnosis Guide
  Complete Baxi 800/600/400 error code guide: E133, E119, E125, E128, E131, E168 with diagnosis and fixes
• Blocked Drain Diagnosis: Rodding vs Jetting, Root Infiltration and When to CCTV Survey
• Boiler Ignition Parts Fault Finding: Spark Electrode, Gas Valve, PCB, Flame Sensor and Ignition Lead Diagnosis
  Gas Safe ONLY (GSIUR 1998); ignition chain PCB→spark electrode→gas valve→ionisation probe; gap 3-4mm, ionisation 1.5-8μA DC, inlet 20mbar standing/17 working; ASCII decision tree; lockout codes by brand; flue CO₂
• Boiler Losing Pressure: Causes, Diagnosis, and Fixes
  Boiler losing pressure: expansion vessel diagnosis, PRV testing, leak detection, filling loop checks
• Boiler Losing Pressure: Expansion Vessel, PRV, Leaks & Microleaks
  Boiler losing pressure: expansion vessel bladder test via Schrader valve, PRV diagnosis, microleak detection including thermal imaging and UV dye
• Boiler Won't Fire: Ignition Faults, No Gas, Lockout Codes and When to Call a Gas Safe Engineer
  Boiler won't fire: gas supply and pressure checks first (60%+ of calls), ASCII diagnostic decision tree, error code cross-reference for Worcester/Vaillant/Ideal/Baxi, frozen condensate pipe thawing, Gas Safety Regs 1998
• Bouncy or Springy Floor: Joist Span, Notching Damage & Subfloor Diagnosis
  Bouncy floor diagnosis: joist deflection limit (span/250), notching rules (top/bottom third, 0.07–0.25× span from support), drilling limits, end rot assessment, sistering and mid-span blocking
• Burst Pipe Emergency: Isolation, Temporary Repair and Insurance Claims
  Burst pipe emergency: isolation sequence (stopcock → drain cold tank → immersion/boiler off), 1,000 L/hr flow from 15mm pipe at mains pressure, WRAS-approved permanent repair fittings, insurance documentation before repair
• Circuit Breaker Keeps Tripping: MCB vs RCD, Fault Finding & Megger Testing
  Circuit breaker keeps tripping: MCB vs RCD identification, half-split isolation method for earth faults, 500V Megger insulation resistance testing procedure
• Circulator Pump Noise: Cavitation, Air Lock, Speed Setting and When to Replace vs Repair
  Circulator pump noise: cavitation (blocked strainer, over-speed), air lock bleeding, speed setting optimisation, bearing failure diagnosis, vibration isolation from building structure
• Cracked Walls: Hairline, Stepped, Vertical & Horizontal — When to Worry
  Cracked walls: RICS categories 0–5 (>5mm needs engineer), stepped cracks (differential settlement), horizontal regular cracks (cavity wall tie failure), crack monitoring methods
• Cracks in Brickwork and Render: Diagnosing Structural vs Settlement and Thermal Cracking
• Damp Diagnosis Decision Tree: Rising, Penetrating, Condensation or Leak?
  Damp diagnosis decision tree: rising damp (max 1m), penetrating damp (find entry point), condensation (70% of UK cases), distinguishing tests including moisture meter and salt analysis
• Damp Floor Diagnosis: DPC Failure, Ground Moisture & Subfloor Problems
  Damp floor diagnosis: DPM continuity (must connect to wall DPC), polythene test, surface DPM overlay vs physical relay vs cavity drain membrane, sub-floor ventilation, timber moisture thresholds
• Distribution Board Faults: Dead Circuits, Neutral Connections, Overloaded MCBs and Surge Protection Failure
  BS 7671:2018+A2:2022; dead circuit, open neutral (DANGEROUS), overloaded MCB, loose connections, SPD/AFDD failure; IR test 500V DC <1MΩ=fault; ring final 32A=7.4kW; ASCII decision tree; Part P notifiable
• DPC Failure Diagnosis: Separating Rising Damp from Condensation and Penetrating Damp
• Dripping Tap Diagnosis: Washer, Cartridge, O-Ring & Seat Damage
  Dripping tap diagnosis: tap washer replacement, ceramic disc cartridge, O-ring and gland packing, tap seat re-seating for scored brass seats
• EV Charger Fault Finding: Error Codes, Communication Failures, Supply and Earth Faults
  BS 7671 Section 722; 6mA DC detection (RDC-DD or Type B RCD); open-PEN protection on PME; Control Pilot comms fault; CT load mgmt; smart-schedule defaults; supply/comms/earth/device branches
• Extractor Fan Not Working: Power, Timer, Humidity Sensor & Motor Fault Diagnosis
  Extractor fan fault-finding decision tree: power check, timer module test, humidity sensor bypass, motor winding test, shaded-pole vs PSC motor identification, bypass control module failure
• Fault Finder: Cold Radiators — Diagnosis & Fix
  Cold radiator fault-finding decision tree: bleed for air, TRV pin stuck diagnosis, lockshield closed check, sludge/magnetite symptoms (hot top/cold bottom), zone valve manual override test, system balancing
• Fault Finder: Dimmer Switch Problems — Diagnosis & Fix
  Dimmer problems decision tree: leading-edge vs trailing-edge compatibility, minimum load requirements, LED flickering causes, no-neutral smart dimmer solutions, multi-gang derating, winding/screw terminal checks
• Ferroli Boiler Error Codes: Common Faults & Reset Procedures
  Ferroli Modena/DOMIproject error codes: A01 ignition, A04 pressure, F05 overheat, F11 fan — PCB availability warning for older Modena HE; ghost flame F36 is urgent
• Flickering Lights Diagnosis: Loose Connections, MCB Issues and Dimmer Compatibility
• Flickering Lights: Diagnosis Decision Tree — Loose Connection, Neutral Issue or Supply Problem
  Flickering lights diagnosis: loose neutral in ceiling rose, LED dimmer incompatibility, whole-house flicker (supply fault), decision tree and loop-in wiring inspection
• Foundation Movement Fault Finder: Subsidence, Heave, Settlement, and Shrinkage Cracks
  Foundation movement decision tree: subsidence vs settlement vs heave vs thermal movement, BRE Digest 251 crack categories 0–5, monitoring pins, structural engineer triggers
• Frozen Pipe Diagnosis and Thawing: Safe Methods, Burst Risk and What to Do After
• Gas Boiler Not Lighting: Gas Valve Test, Ignition Electrode, Thermocouple and When to Escalate to Gas Safe Engineer
  Gas valve pressure test (20 mbar), ignition electrode gap 3–4mm and cracking check, thermocouple millivolt test, lockout codes, when Non-Gas Safe work stops and engineer needed
• Gas Smell in Property: Emergency Procedure, Tightness Test Sequence and Unsafe Situation Classification
  Gas smell emergency procedure: ECV isolation, 0800 111 999, tightness test sequence, unsafe situation classification (ID1, AR, NCS) per IGEM/UP/10
• Glow-worm Boiler Error Codes: Complete Diagnosis Guide
  Glow-worm Energy/Ultimate error codes (shared Vaillant platform): F.22, F.28, F.29, F.75 with diagnosis
• Heat Pump Defrost Cycle Faults: Normal vs Excessive, Frost Sensor Failure and F-Gas Faults
  Normal defrost every 30-90min, 2-10min; excessive = refrozen drain / fouled coil / failed frost sensor / stuck reversing valve / low charge; condensate drain most common; refrigerant = F-Gas
• Heating Pump Faults: Air Lock, Wrong Speed Setting, Cavitation, Flow Rate and Replacement Decision Guide
  Air lock vs wrong speed vs cavitation vs sludge; pump warm/no flow signature; bleed, speed setting, head/flow matching; replacement decision; ASCII decision tree; complements radiator-cold-bottom and system-cleansing
• Hot Water Not Heating on Combi Boiler: Diverter Valve Test, Flow Sensor, Heat Exchanger Scaling and DHW Thermistor Diagnosis
  Combi diverter valve test (10Ω coil check), DHW flow sensor minimum 2 l/min, secondary heat exchanger descaling, thermistor resistance-temperature table and replacement
• Ideal Boiler Error Codes: Complete Diagnosis Guide
  Complete Ideal Logic error code guide: L2, L5, F1, F2, FD, LC and more with diagnosis steps and parts
• Immersion Heater Fault Finding: Element Testing, Thermostat Diagnosis and E7 Wiring
  Immersion heater fault finding: 500V Megger insulation test (>1MΩ = healthy), element continuity ~17.5Ω for 3kW, thermostat continuity test, Economy 7 two-circuit wiring (RTS-switched bottom element), GS38 safe isolation procedure
• Intergas Boiler Error Codes: Common Faults & Reset Procedures
  Intergas HRE boiler error codes: E1 ignition failure, E2 low pressure, E6 fan fault with sub-code reference table and reset procedures
• Intermittent Hot Water: Thermostatic Cartridge, Diverter Valve, Scale Build-up Decision Tree
  Localise one outlet (TMV/shower cartridge, diverter) vs all outlets (combi diverter valve, scale, flow-firing threshold); combi fires on flow; plate-HEX descale; TMV2/3 servicing
• Leaking Radiator: Valve, Spindle, Body & TRV Diagnosis
  Leaking radiator diagnosis: valve gland, TRV body, pinhole corrosion — repairs without draining the system, inhibitor recharge
• Limescale in Heating Systems: Diagnosing Scale Build-Up in Cylinders, Boilers and Pipes
• Lintel Failure Diagnosis: Arch Action vs Lintel Deflection, Spalling Above Openings, Rusted Steel, Propping and Replacement
  Arch action vs lintel deflection diagnosis, spalling above opening (rusted steel expansion), step cracking pattern identification, propping with Acrow props before removal, replacement lintel bearing 150mm minimum
• Low Shower Pressure: Combi, Gravity, Electric Diagnosis — Pump, Blockage and PRV Fault Finding
  Low shower pressure: combi vs gravity vs electric system-specific diagnosis, PRV testing, thermostatic cartridge limescale, shower pump selection (positive vs negative head), mains pressure check
• Macerator Problems: Blocked, Humming, Not Flushing, Blade Wear and Reset Procedure
  Humming (jam/membrane), continuous run (NRV/pressure switch), dead (thermal cutout), slow (worn blades/scale/discharge); 3 Ps only; BS EN 12050-3; Part H; isolate before opening
• Main (Baxi) Boiler Error Codes: Common Faults & Reset Procedures
  Main Eco Compact error codes: E133 ignition, E119 pressure, E125 APS, E160 overheat — BDR Thermea platform; compact installation condensate trap access notes
• Navien Boiler Error Codes: Common Faults & Reset Procedures
  Navien NCB error codes: E003 ignition failure, E407 low pressure, E027 overheating, E110 scale build-up with reset procedures
• No Heating But Hot Water Works: Motorised Valve, Thermostat & Programmer Diagnosis
  No heating but hot water works: Y-plan mid-position valve vs S-plan 2-port valve diagnosis, programmer, and thermostat checks
• No Hot Water from the Boiler: Step-by-Step Diagnosis for Combi, System and Regular Boilers
• No Hot Water: Step-by-Step Diagnostic Decision Tree
  No hot water diagnostic decision tree: separate paths for combi, system, and regular boilers with component-level diagnosis
• No Power to a Circuit: MCB Tripped, RCBO Fault or Broken Ring - Step-by-Step Diagnosis
• Noisy Pipes: Water Hammer, Air Locks, Expansion & Flow Rate Issues
  Noisy pipes: water hammer and shock arrestors, thermal expansion ticking at pipe clips, air lock purging in gravity systems, heating system kettling and pump cavitation
• Outdoor Lights Not Working: PIR Sensors, Photocells, IP Ratings & Earthing Faults
  Outdoor lights fault-finding decision tree: PIR range/sensitivity adjustment, photocell (LDR) test, LED driver failure, IP rating assessment, cable damage from frost, earth fault diagnosis
• Overflowing Cistern: Ball Valve, Float, Washer & Inlet Pressure Diagnosis
  Overflowing cistern: ball valve washer failure, waterlogged float, high inlet pressure, and upgrading to diaphragm valve
• Pipe Joint Leak Diagnosis: Solder vs Compression vs Push-Fit Failure Modes and Repair Without Full Drain-Down
  Solder capillary failure (cold joint vs flux residue), compression nut overtightening, push-fit collet and O-ring diagnosis, localised repair without full drain-down using freeze kit
• Potterton Boiler Error Codes: Common Faults & Reset Procedures
  Potterton Promax/Titanium error codes: E133 ignition, E119 pressure, E125 APS, E160 overheat — BDR Thermea platform shared with Baxi; LED flash codes for older Performa/Gold
• Radiator Cold at the Bottom: Causes, Diagnosis, and Solutions
  Radiator cold at bottom: magnetite/sludge diagnosis, powerflush vs chemical flush comparison, replacement criteria
• RCBO Keeps Tripping: Individual Circuit Diagnosis, Earth Fault vs Overcurrent vs RCD Element
  RCBO keeps tripping: MCB vs RCD element identification, earth leakage half-split isolation, insulation resistance testing, nuisance tripping from capacitive loads, Type A vs AC RCBO
• RCD Keeps Tripping: Systematic Diagnosis Guide
  RCD keeps tripping: half-split isolation method, earth fault finding, common causes by room, nuisance tripping diagnosis
• Sagging Roof: Rafter Failure, Purlin Problems & When to Call a Structural Engineer
  Sagging roof: rafter vs purlin failure diagnosis, collar tie function, eave spread indicators, sistering and purlin replacement procedure, emergency Acrow propping, structural engineer triggers
• Shower Problems: Low Pressure, Thermostatic Failure, No Hot Water & Flow Rate Diagnosis
  Shower problems decision tree: low pressure (gravity vs combi), thermostatic cartridge replacement, electric shower element failure, scale build-up, diverter valve fault, water temperature instability
• Smart Home Device Faults: Connectivity, Hub Reset, Firmware Issues and Wiring Checks
  Layered diagnosis network→protocol→device→wiring; 2.4GHz reliance; UK switch-neutral problem; no-neutral bypass/min load; LED dimmer leading vs trailing edge; Z-Wave exclude before re-pair; BS 7671/Part P
• Socket Not Working: How to Diagnose a Dead Socket
  Dead socket diagnosis: MCB checks, ring final circuit testing, back-stabbed connections, broken ring identification
• Thermostat Not Controlling Heating: Wiring, Placement & Compatibility Issues
  Thermostat not controlling heating: 2-wire vs 3-wire (neutral) wiring, zone valve motorhead testing, thermostat placement rules, OpenTherm terminal wiring
• Tile Cracking and Debonding: Diagnosing Substrate Movement, Wrong Adhesive and Poor Grouting
• Toilet Won't Stop Running: Float Valve, Flapper, Overflow & Siphon Diagnosis
  Toilet won't stop running: siphon diaphragm vs flap valve diagnosis, float valve adjustment and replacement, food colouring silent leak test (~400 L/day waste)
• Total Power Loss: Supply Fault, Main Switch, RCD or Consumer Unit Diagnosis
  Total power loss diagnosis: supply fault, DNO cut-out, main switch, RCD, and split-load board isolation
• Vaillant Boiler Error Codes: Complete F-Code Diagnosis Guide
  Complete Vaillant ecoTEC F-code guide: F22, F28, F29, F75 and 15+ codes with causes, diagnosis steps, and parts needed
• Viessmann Boiler Error Codes: Common Faults & Reset Procedures
  Viessmann Vitodens F-codes: F4 ignition failure, F9 overheat, EA low pressure, F5 pump fault — reset procedure and ViCare app remote diagnostics
• Water Hammer in Pipes: Causes, Diagnosis and Fixes for Hammering and Banging Noises
• Water Quality Fault Finder: Discoloured, Smelly, or Unusual-Tasting Water
  Water quality decision tree: brown/orange, blue-green staining, black particles, white particles, rotten egg smell, chlorine taste, metallic taste — causes and actions per Water Supply Regulations 1999
• Wet Underfloor Heating Fault Finding: No Heat, Uneven Zones & Pressure Loss Diagnosis
  Wet UFH fault-finding decision tree: actuator testing, manifold balancing, zone pressure loss, air in system, pump direction check, screed cracking over pipe, commissioning documentation
• Wet Wall Diagnosis: Penetrating Damp vs Condensation vs Plumbing Leak
  Wet wall diagnosis: penetrating damp vs condensation vs plumbing leak decision matrix, polythene test, calcium carbide test, thermal imaging, resistance damp meter salt limitations
• Worcester Bosch Error Codes: Complete Diagnosis Guide
  Complete Worcester Bosch Greenstar error code guide: EA, A1, D1, E5, E9, C6 and more with diagnosis steps