Fault Finder

87 articles

• AFDD Nuisance Tripping: Causes & Half-Split Isolation 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 Faults: Error Codes & Low COP Guide
  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 Pipes: Water Hammer, Expansion Noise & 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, Jetting & CCTV Survey
• Blocked Toilet: Diagnosis Before Calling a Drain Specialist
  Blocked toilet 3-min diagnosis: (1) what was flushed (2) other outlets draining? (3) LIFT nearest IC — empty=upstream/pan block use plunger+auger, full=downstream needs rods from CLEAR chamber back upstream, clockwise-rotation only; boundary responsibility split at Water Industry Act s105A
• Boiler Kettling: Causes, Diagnosis and Cure
  Boiler kettling (rumbling/banging) from limescale or magnetite sludge restricting the heat exchanger; chemical flush, power flush, magnetic filter, scale reducer; decision tree; BS 7593 water treatment
• 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 Diagnosis
  Boiler losing pressure: expansion vessel bladder test via Schrader valve, PRV diagnosis, microleak detection including thermal imaging and UV dye
• Boiler Not Igniting: Spark Electrode & Gas Valve 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 Won't Fire: Ignition Faults & Lockout Codes UK
  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 Floor Diagnosis: Joist Span, Notching & Repairs
  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 Guide
  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 Tripping: MCB vs RCD Fault Finding Guide
  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 & Repair Guide
  Circulator pump noise: cavitation (blocked strainer, over-speed), air lock bleeding, speed setting optimisation, bearing failure diagnosis, vibration isolation from building structure
• Combi Boiler No Hot Water But Heating Works: Repair Guide
  Combi diverter valve test (10Ω coil check), DHW flow sensor minimum 2 l/min, secondary heat exchanger descaling, thermistor resistance-temperature table and replacement
• Condensation on Windows: Causes and Ventilation Fixes
  Window condensation = warm moist air hitting cold glass below dew point; cure by reducing moisture + ventilation (extract fans, trickle vents), warm-edge/low-e units; black-mould link; Part F, Part L
• Cracked Walls: When to Worry & What Each Crack Type Means
  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: Structural vs Thermal Movement Guide
• Damp Diagnosis Guide: Rising, Penetrating or Condensation
  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 Causes: DPM Failure, DPC & Subfloor Issues UK
  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: Diagnosis & Repair Guide UK
  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: Rising Damp vs Condensation UK
• Dripping Tap Repair: Washer, Cartridge & O-Ring Guide
  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 & Supply 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: Motor & Power 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 Diagnosis: Electric Shower Not Working
  Electric shower fault tree: MCB tripped, inlet solenoid, flow switch, heating element, TCO; isolation procedure (32-50A circuits); BS 7671 bathroom Zone 1 IPX4 + Part P notifiable
• Fault Diagnosis: Extractor Fan Not Working
  Extractor fan fault tree with ASCII decision tree: triple-pole isolator, switched live, motor seizure, duct blockage, condensate; Part F rates (8/15/30/60 l/s), Part P notification, dMEV vs MEV vs intermittent
• Fault Diagnosis: Leaking Toilet Cistern
  Leaking toilet cistern diagnosis: flush-valve trickle vs fill-valve overflow vs donut washer vs pan-bolt washers; Fluidmaster universal replacement; Part G dual-flush; WRAS-approved fittings
• Fault Diagnosis: Radiator Cold at Top or Bottom
  Radiator cold-top = air (bleed); cold-bottom = sludge/magnetite (power flush + inhibitor + magnetic filter); cold-all-over = flow problem (TRV/lockshield/pump); BS 7593:2019 inhibitor/filter compliance
• Fault Diagnosis: Tap Dripping or Spluttering
  Tap dripping/spluttering diagnosis: compression washer vs ceramic cartridge, aerator blockage, isolation valve, splutter from air/PRV/blocked aerator/DHW cylinder issue; WRAS-approval and Water Fittings Regs 1999
• 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 UK: Diagnosis & Fix Guide
• Flickering Lights: Diagnosis Guide for UK Electricians
  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 Cracks: Subsidence vs Settlement Guide
  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 Pipes UK: How to Thaw Safely & Prevent Bursts
• Gas Boiler Not Lighting: Gas Safe Diagnosis Guide 2024
  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
  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 UK
  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, Speed & Cavitation 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
• 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 & Thermostat Testing
  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: Faults & Reset Guide UK
  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: Diagnosis & Fix Guide UK
  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
• Light Switch Buzzing: Dimmer Compatibility and LED Driver Issues
  Light switch buzzing diagnosis: dimmer + LED compatibility (LED needs trailing-edge/electronic dimmer), transformer harmonic buzz on halogens, MEM/rocker switch mechanical wear, capacitive coupling in 2-way circuits; fix: swap dimmer, replace switch, or dedicated LED driver
• Limescale in Heating Systems: Diagnosis & Treatment Guide
• Lintel Failure: Diagnosis, Cracking & Replacement Guide
  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 Mains Water Pressure: Causes and Fixes
  Low mains water pressure — diagnose vs internal flow restriction; min 1 bar / 9 L/min at boundary stopcock; PRVs, shared supply, partially-closed valves, narrow lead pipe; decision tree; Water Industry Act 1991, GSS
• Low Shower Pressure: Combi, Gravity & Electric Diagnosis
  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 Not Working: Blocked, Humming & Won't Flush Fix
  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 Boiler Error Codes: E133, E119, E125 & Reset Guide
  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: Valve & Thermostat Fix
  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 but Heating Works: Diverter Valve Diagnosis
  No hot water but heating works on a combi — prime suspect the diverter valve; also flow switch, DHW thermistor, scale; decision tree and test sequence; Gas Safe for gas-side work
• No Hot Water from Boiler: Diagnosis Guide for UK Homes
• 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 Circuit: MCB, RCBO & Ring Fault Diagnosis
• Noisy Pipes: Water Hammer, Air Locks & Thermal Expansion
  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, Photocell & IP Rating Guide
  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 Diagnosis Guide
  Overflowing cistern: ball valve washer failure, waterlogged float, high inlet pressure, and upgrading to diaphragm valve
• Pipe Joint Leak Repair: Solder, Compression & Push-Fit
  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: Fault Guide & Reset Steps
  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 Bottom: Sludge Causes & Fix Guide
  Radiator cold at bottom: magnetite/sludge diagnosis, powerflush vs chemical flush comparison, replacement criteria
• RCBO Keeps Tripping: Fault Diagnosis & Fix Guide UK
  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 & Purlin Failure Diagnosis Guide
  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 Pressure Problems: Low Flow & Temperature Fix Guide
  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
• Shower Runs Cold After Hot: Combi, Cylinder and Mixer Diagnosis
  Shower cold-after-hot diagnosis: combi PHE scaling / undersized boiler (70% of calls), diverter valve sticking, cylinder empty (unvented 8-15 min), TMV pressure imbalance, cartridge cross-flow; two-outlet test (kitchen tap + shower) isolates upstream vs valve
• Smart Home Device Faults: Connectivity & Wiring Guide
  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 Fix
  Thermostat not controlling heating: 2-wire vs 3-wire (neutral) wiring, zone valve motorhead testing, thermostat placement rules, OpenTherm terminal wiring
• Tile Cracking & Debonding: Diagnosis & Repair Guide
• Toilet Won't Stop Running: Flapper & Float Valve Fix Guide
  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 & 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: F4, F9 & EA Reset Guide
  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 & Fixes Guide UK
• Water Quality Problems: Discoloured, Smelly Water Diagnosis
  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 Not Working: Fault Finding Guide
  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: Damp vs Condensation vs Leak Guide
  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