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Squotipedia
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Fault Finder
Fault Finder
57 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
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
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
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
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 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
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
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
Leaking Radiator: Valve, Spindle, Body & TRV Diagnosis
Leaking radiator diagnosis: valve gland, TRV body, pinhole corrosion — repairs without draining the system, inhibitor recharge
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
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: Step-by-Step Diagnostic Decision Tree
No hot water diagnostic decision tree: separate paths for combi, system, and regular boilers with component-level 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
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
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 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