Exploded Diagrams
Diagram Key:
- Refer to item numbers on diagrams
- Match numbers with parts list
- Use Quincy part numbers when ordering
- Diagrams show assembly relationships
Major Assembly Diagrams
- Compressor Pump Assembly: Complete breakdown of cylinder, piston, valves and connecting rods.
- Motor & Drive Assembly: Motor mounting, pulley system, belts and tensioning mechanism.
- Tank & Valve Assembly: Pressure tank, safety valves, pressure switches and gauges.
- Control Panel Assembly: Electrical controls, switches, regulators and instrumentation.
- Frame & Mounting Assembly: Structural components, wheels, handles and mounting hardware.
- Air System Assembly: Piping, filters, regulators and lubricators.
- Cooling System Assembly: Fan, shroud and cooling fin components.
Parts List
| Model Series | 5120-XXX (Various configurations) |
| Compressor Type | Reciprocating Piston, Two-Stage |
| Pump Model | QT-5 Series |
| Maximum Pressure | 175 PSI |
| CFM at 175 PSI | 24.1 CFM |
| Horsepower | 7.5 HP |
| Tank Size | 80 Gallon ASME |
| Motor Type | TEFC, 3-Phase or Single Phase |
| Voltage Options | 230V/460V 3-Phase, 230V Single Phase |
| Dimensions (LxWxH) | 72 x 38 x 75 inches |
| Weight | 850 lbs |
| Sound Level | 78 dBA |
Warranty Information
- Pump Warranty: 5 years limited warranty
- Tank Warranty: Lifetime limited warranty
- Parts Warranty: 1 year on replacement parts
- Labor Warranty: 90 days on authorized repairs
For warranty service, contact Quincy Compressor at 1-800-861-3344 or visit QuincyCompressor.com
Specifications
QT-5 Pump Design
Quincy's patented two-stage design provides cooler operation, longer life, and superior efficiency with large diameter crankshaft and precision bearings.
Pressure Lubrication System
Full pressure lubrication ensures proper oil flow to all critical components including crankshaft, connecting rods, and bearings for maximum durability.
Intercooler & Aftercooler
Built-in intercooler between stages and aftercooler after final stage reduces moisture and increases efficiency by cooling air between compression stages.
Heavy-Duty Construction
Cast iron construction throughout with ductile iron crankshaft, aluminum alloy pistons, and stainless steel valves for industrial-grade reliability.
ASME Certified Tank
80-gallon ASME certified tank with corrosion protection and dual drain valves for maximum safety and durability in demanding environments.
Advanced Control System
Microprocessor-based control with automatic dual control, hour meter, and diagnostic capabilities for optimal performance monitoring.
Pump Component Breakdown
Cylinder Assembly
Cast iron cylinders with replaceable sleeves, includes valves and valve plates
Piston & Rod Assembly
Aluminum alloy pistons with piston rings and forged steel connecting rods
Crankshaft Assembly
Ductile iron crankshaft with precision bearings and counterweights
Valve System
Stainless steel reed valves with valve plates and springs
Lubrication System
Oil pump, filter, passages and pressure regulation components
Cooling System
Intercooler, aftercooler, fan and cooling fin assemblies
Maintenance Parts
| Part Description | Part Number | Maintenance Interval |
|---|---|---|
| Air Filter Element | Q-5120-FIL | 500 hours or 6 months |
| Oil Filter Cartridge | Q-5120-OIL | 1000 hours or annually |
| Compressor Oil (Gallon) | Q-5120-OIL1 | Check weekly, change annually |
| Drive Belt Set | Q-5120-BELT | 2000 hours or as needed |
| Safety Valve | Q-5120-SAFE | Test monthly, replace every 2 years |
| Pressure Switch | Q-5120-SWCH | 5 years or as needed |
| Piston Ring Set | Q-5120-RING | 10,000 hours or as needed |
| Valve Plate Kit | Q-5120-VALV | 10,000 hours or as needed |
| Bearing Kit (Complete) | Q-5120-BEAR | 20,000 hours or as needed |
| Gasket Set (Complete) | Q-5120-GASK | During major overhaul |
Common Replacement Kits
- Overhaul Kit - Basic: Includes piston rings, gaskets, valves (Q-5120-OH1)
- Overhaul Kit - Complete: Includes bearings, seals, all wear parts (Q-5120-OH2)
- Maintenance Kit: Filters, oil, belts, basic consumables (Q-5120-MNT)
- Valve Repair Kit: Complete valve assembly with plates (Q-5120-VRK)
- Bearing Kit: All bearings and seals for pump (Q-5120-BRK)
- Control Repair Kit: Pressure switch, gauges, unloader (Q-5120-CRK)
Ordering Information
Current Model Parts
5120-230V1
Single Phase 230V Version
5120-230V3
3-Phase 230V Version
5120-460V3
3-Phase 460V Version
5120-QSV
Quincy Silent Version
Related Models & Parts
QT-5 Pump Parts
Complete pump assembly parts
5100 Series
5 HP Related Models
5200 Series
10 HP Related Models
Accessories
Dryers, Filters, Drains
Parts Ordering Guidelines
- Locate your compressor's serial number plate (usually on tank or pump)
- Identify the exact model number (5120-XXX format)
- Reference the exploded diagram for correct part numbers
- Note any variations or modifications to your specific unit
- Contact authorized Quincy distributor for pricing and availability
- Keep records of all part replacements for warranty purposes