# AirCompDX > Field reference for air compressor technicians: symptom-driven diagnostics, NEC motor data, pump-up tests, electrical reference, OEM manual links, controller fault-code lookups, and preventive-maintenance guides. Covers reciprocating, rotary screw, scroll, oil-less, and high-pressure compressors plus vacuum pumps, dryers, filters, and drains. Works offline as an installable PWA. AirCompDX is built and maintained by working air-compressor service techs. Every page is written for jobsite use: no marketing filler, straight to the symptom → cause → field check → fix flow, with links to the exact calculator, wiring reference, or OEM manual portal a tech needs to close out the call. Topics covered in depth: air compressor won't start / won't build pressure / trips breaker / short-cycles / overheats / oil carryover / wet air, single-phase and three-phase motor wiring, wye-delta and soft starters, VFD faults, contactor and overload sizing, pressure-switch wiring and cut-in/cut-out setup, receiver-tank and pipe sizing, pump-up CFM tests, leak-cost calculations, refrigerated and desiccant dryer PM, brand-specific troubleshooting for Ingersoll Rand, Quincy, Champion, Sullair, Atlas Copco, Kaeser, Campbell Hausfeld, Curtis, DeWalt, Husky, Kobalt, Craftsman, Porter-Cable, Bostitch, Ryobi, Central Pneumatic, California Air Tools, and HDX, and controller fault codes for Sigma Control 2, Elektronikon, Xe-series, Supervisor, and GD Pilot. ## Diagnostics - [Diagnose index](/diagnose): Symptom-driven troubleshooting hub — pick a symptom, get likely causes and field checks. - [Won't start / motor hums](/diagnose/wont-start): Capacitor, unloader, pressure switch, and thermal overload checks. - [Trips breaker or blows fuse](/diagnose/trips-breaker): Motor FLA, voltage drop, and short-circuit tests. - [Low discharge pressure](/diagnose/low-pressure): Reed valves, gaskets, unloader, and pump-up test. - [High discharge pressure / relief lifting](/diagnose/high-pressure): Pressure switch cut-out, PRV, and controller setpoints. - [Short cycling](/diagnose/short-cycling): Tank leaks, check valve, differential, and receiver sizing. - [Slow pump-up](/diagnose/slow-pump-up): Actual CFM vs demand, worn pump, intake restriction. - [Runs hot / high temperature trip](/diagnose/high-temp): Cooling airflow, oil condition, ambient, duty cycle. - [Controller fault](/diagnose/controller-fault): Reading and clearing fault codes on major OEM controllers. - [Load / unload stuck](/diagnose/load-unload-stuck): Inlet valve, solenoid, and blowdown valve diagnosis. - [Low oil pressure (screw)](/diagnose/low-oil-pressure): Oil pump, thermostatic valve, filter ΔP. - [Oil consumption (recip)](/diagnose/oil-consumption-recip): Rings, breather, oil level, viscosity. - [Oil carryover (screw)](/diagnose/oil-carryover): Separator element, scavenge line, return orifice. - [Wet air in lines](/diagnose/wet-air): Dryer sizing, drains, aftercooler, and separator placement. - [Drain stuck](/diagnose/drain-stuck): Timer, solenoid, and demand-drain troubleshooting. - [Belt issues](/diagnose/belt-issues): Tension, alignment, sheave wear, and slip. - [Dryer high dewpoint](/diagnose/dryer-high-dewpoint): Refrigerated dryer diagnostics. - [Desiccant bypass](/diagnose/desiccant-bypass): Tower switching, purge, and pressure-dewpoint checks. - [Noise diagnosis](/diagnose/noise): Bearing, valve, and slap identification. - [VSD fault](/diagnose/vsd-fault): Drive faults, DC bus, and cooling issues. - [Wye-delta issues](/diagnose/wye-delta): Transition timing, contactor sequencing. - [Contactor problems](/diagnose/contactor): Chatter, welded contacts, coil voltage. ## Calculators - [Calculators index](/calculators): All field calculators in one place. - [Motor amps / FLA](/calculators/motor-amps): NEC 430 motor full-load amps by HP and voltage. - [Motor data table](/calculators/motor-data): NEC motor tables for wire and overload sizing. - [Voltage drop](/calculators/voltage-drop): Sized-cable voltage drop for compressor circuits. - [Pump-up CFM](/calculators/pump-up): Actual delivered CFM from tank pump-up time. - [Belt length](/calculators/belt-length): V-belt length from sheave diameters and center distance. - [Receiver sizing](/calculators/receiver): Tank size for peak demand and cycle time. - [Pipe sizing](/calculators/pipe): Header pipe diameter for target pressure drop. - [Pipe properties](/calculators/pipe-properties): Schedule 40/80 pipe ID, OD, and pressure ratings. - [Leak cost](/calculators/leak): Annual energy cost from measured leaks. - [Pressure conversion](/calculators/pressure): PSI, bar, kPa, inHg conversions. - [Compression ratio](/calculators/compression-ratio): Stage ratio for multi-stage compressors. - [Pressure switch](/calculators/pressure-switch): Cut-in / cut-out / differential setup. - [CFM correction](/calculators/cfm): SCFM, ACFM, ICFM conversions with altitude and humidity. - [Dewpoint](/calculators/dewpoint): Pressure vs atmospheric dewpoint conversion. - [Condensate load](/calculators/condensate): Water removal by SCFM, temperature, and RH. - [Dryer capacity](/calculators/dryer-capacity): Refrigerated dryer sizing with correction factors. - [ΔP cost](/calculators/dp-cost): Cost of pressure-drop across filters and dryers. - [Oil aging](/calculators/oil-aging): Fluid life vs discharge temperature. - [Oil compatibility](/calculators/oil-compatibility): OEM fluid mixing and flush guidance. - [Unit converter](/calculators/unit-converter): Pressure, flow, power, temperature. - [HVAC load, superheat, subcool, ΔT, balance point, SEER cost](/calculators): HVAC calculators for techs also servicing air conditioning. ## Reference - [Electrical reference](/electrical): Wye-delta, soft starters, contactors, overloads, VFDs, single- and three-phase wiring. - [Motor repair reference](/reference/motor-repair): Winding tests, capacitor sizing, insulation resistance. - [Reference index](/reference): Reciprocating, rotary screw, scroll, oil-less, high-pressure, and vacuum pump theory. - [Pressure switches](/pressure-switches): Wiring, cut-in/cut-out adjustment, differential, replacement, common part numbers. - [Parts cross-reference](/parts): Common wear-part cross-references across brands. - [Glossary](/glossary): Compressor and pneumatic-system terminology. ## Brands & models - [Troubleshooting hub](/troubleshooting): System-by-system troubleshooting with safety rules. - [Brand troubleshooting index](/troubleshooting/brands): Common symptoms, causes, and fixes by brand. - [Ingersoll Rand](/troubleshooting/brands/ingersoll-rand): T30, 2545, UP6, R-Series, Nirvana. - [Quincy](/troubleshooting/brands/quincy): QT, QR-25, QGV, QSI. - [Champion](/troubleshooting/brands/champion): R/HR-Series and Rotorchamp. - [Sullair](/troubleshooting/brands/sullair): LS, ES, and portable tow-behind units. - [Atlas Copco](/troubleshooting/brands/atlas-copco): GA, GX, ZR, ZT with Elektronikon. - [Kaeser](/troubleshooting/brands/kaeser): SK, SM, AS, CS with Sigma Control. - [Campbell Hausfeld](/troubleshooting/brands/campbell-hausfeld): VT/VX two-stage and XC contractor units. - [Curtis-Toledo](/troubleshooting/brands/curtis): Masterline and CA-Series. - [DeWalt](/troubleshooting/brands/dewalt): D55146, D55168, DXCM series. - [Husky](/troubleshooting/brands/husky): C601H, C602H, C801H, H1820F. - [Kobalt](/troubleshooting/brands/kobalt): QT-215, SGY-AIR, 60-gal 2-stage. - [Craftsman](/troubleshooting/brands/craftsman): 919-series and CMEC / CMXECXA. - [Porter-Cable](/troubleshooting/brands/porter-cable): C2002, CMB15, C2005 pancakes. - [Bostitch](/troubleshooting/brands/bostitch): BTFP02012 and CAP series. - [Ryobi](/troubleshooting/brands/ryobi): P737, P739, YN301PL1. - [Central Pneumatic (Harbor Freight)](/troubleshooting/brands/central-pneumatic): Budget single-stage recips. - [California Air Tools](/troubleshooting/brands/california-air-tools): Ultra-quiet oil-free and oil-lubricated units. - [HDX](/troubleshooting/brands/hdx): Home Depot budget pancakes and hotdogs. - [Compressor models](/models): Specs, wear parts, PM cadence, controller cross-refs across 20+ brands. - [Controllers](/controllers): Sigma Control 2, Elektronikon, Xe-series, Supervisor, GD Pilot fault codes. - [OEM manuals](/manuals): Manual portals and per-brand model search. ## Service guides (PM & rebuild) - [Guides index](/guides): Step-by-step service and PM procedures. - [Single-stage pump rebuild](/guides/single-stage-pump-rebuild) - [Two-stage pump rebuild](/guides/two-stage-pump-rebuild) - [Valve plate service](/guides/valve-plate-service) - [Screw airend PM](/guides/screw-airend-pm) - [Air/oil separator change](/guides/air-oil-separator-change) - [Scroll tip seal service](/guides/scroll-tip-seal) - [Vacuum pump oil & vanes](/guides/vacuum-pump-oil-vanes) - [Oil-less recip rebuild](/guides/oilless-recip-rebuild) - [Unloader & pressure switch replacement](/guides/unloader-and-pressure-switch) - [Check valve & safety relief](/guides/check-valve-and-srv) - [Magnetic starter & overload](/guides/magnetic-starter-and-overload) - [Belt & sheave alignment](/guides/belt-and-sheave-alignment) - [Oil change & break-in](/guides/oil-change-and-break-in) - [Intake filter PM](/guides/intake-filter-pm) - [Refrigerated dryer PM](/guides/refrigerated-dryer-pm) - [Desiccant dryer PM](/guides/desiccant-dryer-pm) - [Husky-specific troubleshooting guide](/guides/husky-troubleshooting) ## Air treatment & downstream - [Air treatment index](/air-treatment): Dryers, filters, drains, aftercoolers. - [HVAC diagnostics](/hvac): AC and heat-pump diagnostics for crossover techs. - [Nearby pros](/nearby): Find local compressor service companies. ## Blog & long-form - [Blog](/blog): Field write-ups, controller deep-dives, and case studies. - [Library](/library): Curated links to standards (NEC, ASME, ISO 8573) and OEM literature. ## Optional - [Sir Pumps-A-Lot AI](/ai): In-app compressor sidekick chat (requires account). - [Pricing](/pricing): 100% free, no paywall. Optional one-time tips support development. - [Contact](/contact): Reach the AirCompDX team.