Aircon Diagnostic Cases
Diagnostic case notes: the fault pattern, what we tested, what we found, and why we called it that way. Details anonymised, diagnostics intact.
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Cooling issue cases39 pages
- Aircon shutting off mid-cycle: temperature sensor gone bad
- All four rooms went warm: single leak at the outdoor unit
- Bedroom not cold near a park: screen blocked condenser
- Brand-new BTO never felt cold: undercharged from install
- Cafe unit barely cooling: grease sludge on the evaporator
- Cassette not cooling: stuck gas-flow valve, not compressor
- Ceiling unit fading each year: coil buildup a filter misses
- CH38 in one bedroom only: pinhole leak in that indoor coil
- Coastal condo not cold: condenser fins crusted with salt
- Coastal condo not cold: evaporator grime, not a gas leak
- Coastal unit losing gas again: salt ate the pipe fitting
- Cooling faded in every room: the compressor had worn out
- Every zone went warm together: branch distributor leak
- Factory office barely cooling: condenser coated in dust
- Factory office warm again: condenser fan blade cracked
- Five-year-old unit losing cooling: salt crust on condenser
- Flat not cold: condenser fins caked in exhaust grease
- Four-year-old LG losing gas: high-floor wind corroded pipes
- Garden condenser blocked by seed pods: room warm by 3pm
- Gas keeps running out: pinhole leak in pipe behind the wall
- Gas leak returned after weld repair: corroded section
- Gas topped up three times: hidden leak at the service valve
- High bill and weak cooling: outdoor unit undersized
- Ice forming on the copper pipe: airflow blocked, not gas
- Landed home cooling fading: condenser caked with dust
- LG CH35 error in Bedok: gas leak at the outdoor connections
- LG CH38 on a cassette: a loose fitting, not corrosion
- LG system-3 losing gas: leak outdoors, not inside walls
- LG unit topped up twice: corroded outdoor pipe connections
- Multi-split, one bedroom warm: seized expansion valve
- Narrow ledge unit overheats: rear clearance blocked
- Office warm by afternoon: condenser heat trapped in recess
- One side of office warm, other side fine: zone damper stuck
- Outdoor unit barely cooling: condenser fins flattened
- Outdoor unit completely dead: compressor confirmed failed
- Shophouse no cooling: condenser heat trapped in airwell
- Two bedrooms losing cooling together: pinhole coil leak
- Two top-ups in four months: slow leak at indoor pipe joint
- Waterfront shop losing cooling: salt corrosion on the coil
Water & leak cases26 pages
- BTO bedroom leaking at trunking: drain pinched by a shelf
- Cassette dripping onto desks: drain sludge, not a crack
- Cassette leaking after heavy rain: float switch missed load
- Ceiling drip on humid afternoons: gap in the drain pipe
- Ceiling drip with error code: drain pump motor failed
- Ceiling unit dripping after service: drain left loose
- Ceiling unit leaked after power outages: pump needed a reset
- Concealed unit dripping from the panel: drain pump seized
- Condo dripping after renovation: fine dust choked the drain
- Drips only on humid days: mineral buildup narrows the drain
- Error returns after drain clearing: sagging pipe traps mud
- Factory cassette dripping again: dust sludge in the drain
- HDB bedroom drip after years: drain choke behind trunking
- Landed unit drips and smells musty: biofilm in drain tray
- Mall shop cassette dripped late: hose loose at the pump
- New unit drips after first service: drain pan not reseated
- New unit drips in humid weather: bracket out of level
- Older condo trunking drip: insulation gap on a cold pipe
- Older HDB trunking drip: cracked drain elbow behind casing
- Older HDB trunking drip: perished gasket at the access panel
- Restaurant drips mid-service: drain line sags round a beam
- Shop unit dripping near closing: drain pump float jammed
- Shophouse trunking drip: drain backfall after retrofit
- Villa cassette dripping: drain pump overwhelmed by humidity
- Water dripping onto parquet: algae blocking the drain tray
- Water marks on ceiling: drain pump switch stuck by sludge
Power & electrical cases36 pages
- Aircon only trips when it rains: water in the switch box
- All four rooms down at once: outdoor board died
- Auto mode kept shutting off: sensor read the room as cold
- Breaker tripping with a hot smell: damaged isolator
- Capacitor swap didn't fix it: outdoor board was the fault
- Clinic room shuts down after sessions: clogged condenser
- Cooling cuts under load: corrosion at the outdoor terminal
- Ducted system resets itself: a loose terminal, not the board
- Error after neighbour renovation: wire nicked in trunking
- Error after neighbour's renovation: cable insulation nicked
- Error appeared after thunderstorm: connection shaken loose
- Error appeared right after servicing: board locked, not dead
- Error code weeks after renovation: signal wire nicked
- Error only after hours of running: corroded joint in ceiling
- Error returns after every reset: corroded outdoor terminals
- Error returns after every reset: corroded wire connection
- Factory office keeps tripping: corroded isolator switch
- Indoor fan blowing but outdoor silent: faulty starter relay
- New board didn't fix it: the temperature sensor was at fault
- Office error after peak load: drain overflow switch tripped
- Office trips under load: wiring worn at a tight bend
- Office unit trips after long runs: drain float switch stuck
- One unit showing error, others fine: indoor board dead
- Outdoor unit buzzing and clicking: capacitor, not compressor
- Outdoor unit trips after rain: loose isolator terminal
- Outdoor unit trips on start: isolator contact corroded
- Port-side office trips: isolator corroded by salt air
- Pre-war shophouse error: signal wire chafed in trunking
- PRISM+ cassette remote on and off: dust on the sensor
- Random error with no pattern: drain pump cable interference
- Remote stopped working: receiver broken, not the board
- Shophouse trips after rain: sun-cracked cable on the roof
- Shophouse trips after rain: ungasketed isolator cable entry
- Three zones failed overnight: the outdoor control board
- Trips on hot days: weak capacitor, not the compressor
- Whole system shuts down when one room starts: indoor board
Noise & vibration cases35 pages
- Bedroom unit buzzing at night: loose wall bracket
- Block outdoor unit rocks: mounting bolt corroded and seized
- Cassette rattling at certain speeds: loose fan blade clip
- Clinic outdoor unit buzzes: compressor mount rubber hardened
- Condo outdoor unit hums: anti-vibration pads flattened
- Condo outdoor unit wobbles: salt buildup on fan blade
- Factory unit vibrates: mounting isolators perished
- High-rise unit hums: internal compressor mounts perished
- Industrial unit rattles: leveling blocks worked loose
- Jurong West older block rattles: anchor bolts loose in wall
- Landed outdoor unit rattling: bent fan guard touching blade
- Loud rattle on startup that fades: motor bearings worn out
- Low-rise condo bedroom rattles: trunking cover came loose
- New block outdoor unit hums: fan guard resonating in wind
- New block outdoor unit rattles: packing block left behind
- New PRISM+ rattles at certain speeds: panel clip loose
- Office ducted unit whistles: duct clamp loose at high speed
- Office unit hums: suspension rods sitting uneven
- Office unit rattles: refrigerant pipe clips loose
- Older block outdoor unit rattles: storms loosened fan guard
- Older block outdoor unit rocks: sitting on an unlevel base
- Older block outdoor unit taps wall: support frame flexes
- Older estate unit rattles at night: bracket rubber hardened
- Outdoor unit buzzes after a windstorm: fan blade off-centre
- Outdoor unit clicks: fan blade warped by afternoon heat
- Outdoor unit louder at night: mounting rubber hardened
- Outdoor unit rattles in sea breeze: fan guard loosened
- Outdoor unit rattling after storms: leaves behind fan guard
- Rattling every startup: blower wheel loose on the shaft
- Retail unit buzzes: bracket loosened by escalator vibration
- Seafront outdoor unit rattles: rubber mount perished
- Shop ceiling unit buzzes: support rod bolts loosened
- Shophouse outdoor unit rattles: bracket never sat flush
- Shophouse outdoor unit rattles: bracket shaken by traffic
- Unit rocks on hillside ledge: brackets never tightened
Airflow & control cases29 pages
- Canberra flat weak wind: blower loaded with renovation dust
- Cassette airflow weakening: corrosion slowing the fan motor
- Clicking then shutdown: cracked blower catching on housing
- Clinic room weak after hours: return grille packed with lint
- Cold air but barely any wind: dust-caked blower and coil
- Condo bedroom smells musty: wet coil and blocked drain pan
- Condo warm: outdoor unit's air path blocked by hoarding
- Cuts out every afternoon: trapped heat in outdoor alcove
- Ducted system weaker all year: ceiling filter never cleaned
- Factory office weak wind: cassette blower coated in sawdust
- Gallery office not cold: return air blocked by a partition
- Grinding noise then shutdown: fan motor bearings worn out
- Less cold despite regular servicing: deep coil buildup
- New office fit-out not cold: supply grille boxed in
- Office cassette weak airflow: filter loaded with road dust
- Older HDB one room weak: bad filter fit let dust through
- One office zone stayed warm: damper actuator had slipped
- One room warm, other rooms fine: coil buildup, not low gas
- One side of the room always warmer: stuck louver vane
- Outdoor unit running but no air inside: fan motor burnt out
- Persistent musty smell: mould deep inside the cooling coil
- Reservoir-side flat smells musty: blocked fresh-air path
- Retail unit shuts down: condenser blocked in a corridor
- Study always warmer than the rest: airflow damper jammed
- Two sides strong, two sides weak: blower caked on one side
- Waterfront office smells musty: drain tray film, not gas
- Weak airflow in an eatery: cassette blower coated in grease
- Weak despite a clean filter: blower packed behind cover
- Workshop office weak airflow: return filter loaded with dust
Post-service issue cases35 pages
- Bedroom leaked after servicing: drain joint left loose
- Block tripped after servicing: capacitor cover left open
- Café leaked after install: drain line pitched wrong
- Cassette dripping after cleaning: debris in the drain line
- Cassette rattled after service: panel not seated flat
- Condo cassette weak after wash: filter clip not reseated
- Condo leaked after servicing: drain insulation left open
- Condo ran warm after install: energy-saving mode left on
- Condo ran warm after install: line not purged first
- Factory cassette leaked after wash: drain pump hose loose
- Factory unit siphoned water back: valve installed backwards
- Fine before service, warm after: valve left half-closed
- Flat drain backed up after service: outlet cap left on
- Flat leaked after routine service: pump screws left loose
- Flat leaked after servicing: drain hose reseated wrong
- Flat leaked after servicing: drain refitted with poor fall
- Landed home drain pump silent after wash: lead unconnected
- Landed home drain tray filled with dust: grille unlatched
- Landed home tripped in storm: isolator terminal screw loose
- LG CH38 in Toa Payoh: joint loosened during a chemical wash
- New aircon never cooled: line never vacuumed before charging
- New install acting strange: two wires swapped at install
- New LG unit shows CH38: undercharged at install, not a leak
- Noisier and weaker after chemical wash: blower off-centre
- Not cold after pipe work: where to start on a long run
- Office cassette leaked after relocation: hose kinked
- Office cassette leaked after service: pump cover misaligned
- Office zone stayed warm: return damper left closed
- Older block leaked after wash: pump discharge tube crimped
- One office stayed warm after partition works: supply blocked
- Original block leaked after wash: drain inlet not seated
- Original block wouldn't restart: isolator left switched off
- Shophouse leaked after cleaning: drain hose not seated
- Short cycling after service: sensor knocked out of its clip
- Southern Islands villa smelled of drains: new trap left dry
Chemical wash & overhaul cases9 pages
- Airflow fading over a kitchen line: grease-bound fins
- Bill rising while cooling slipped: servicing by calendar
- Each wash bought less time: the coil had reached its end
- Musty smell on every start-up: biofilm across the coil
- Quoted an overhaul on every unit: one blocked drain
- Rental-flat handover: one overhaul, two lighter cleanings
- Told a near-new unit needed a wash: dust on the filter
- Weak airflow after servicing: one fan coil needed more
- Weaker cooling near the sea: salt had eaten the fins
Installation cases9 pages
- Condo install rescoped: an estate condenser placement rule
- Landed house install: drain fall set the whole layout
- Mall shop install: access hours set the work sequence
- New BTO, one warm bedroom: wardrobe blocked intake air
- Office fit-out: return air path decided unit placement
- One indoor unit replaced: the outdoor unit set the limit
- Shophouse airwell install: heat rejection set the position
- Tengah BTO sizing: rooms in use, not bedroom count
- Warm meeting room after fit-out: sensor left in cold zone
Replacement decision cases8 pages
- Clinic repair history: map assets before staging replacement
- Compressor failed at fourteen years: the arithmetic decided
- Office outdoor unit failed: the indoor side set the scope
- Older multi-split: three faults made repairs incomplete
- Partial replacement in a landed home: the copper decided it
- Replacement was recommended: the board was the only fault
- Replacing at a high floor: why we staged it by system
- Third top-up in a year: the pipe run settled it
Cases to start with
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