Exploded Diagrams
Diagram Legend:
- Red: Pump Assembly Components
- Blue: Motor & Drive Components
- Green: Tank & Valve Components
- Yellow: Control & Gauge Components
- Purple: Frame & Mounting Components
Major Assembly Diagrams
- Air Pump Assembly: Complete breakdown of cylinder, piston, connecting rod, and valve plate components.
- Motor & Drive Assembly: Detailed view of motor mounting, pulley system, belts, and tensioning mechanism.
- Tank Assembly: Tank, safety valve, drain valve, check valve, and pressure switch connections.
- Control Panel Assembly: Pressure gauges, regulator, unloader valve, and electrical controls.
- Complete Unit Assembly: Overall assembly showing relationship between all major components.
Parts List
| Model Series | QT & QTS Series 350 |
| Pump Type | Two-Stage Reciprocating |
| HP Range | 5 HP - 7.5 HP |
| Tank Size | 60 Gallon - 80 Gallon |
| Max Pressure | 175 PSI |
| CFM at 175 PSI | 18.1 CFM - 24.5 CFM |
| Cylinder Bore | Stage 1: 4.25", Stage 2: 2.5" |
| Stroke | 3" |
| RPM | 870 RPM |
| Pump Weight | 185 lbs |
Common Replacement Parts
- Piston Rings: Part #QR-350-PR - Set of 4 rings
- Valve Plate Assembly: Part #QR-350-VP - Complete valve assembly
- Connecting Rod: Part #QR-350-CR - Forged steel rod
- Check Valve: Part #QR-350-CV - Tank check valve assembly
- Pressure Switch: Part #QR-350-PS - 175 PSI cut-out
Specifications
Pump Specifications
Two-stage design with cast iron cylinders, forced lubrication system, and intercooler between stages for efficient operation and long life.
Motor Specifications
TEFC (Totally Enclosed Fan Cooled) motor, 230V/460V 3-phase or single phase options, with thermal overload protection.
Tank Specifications
ASME coded vertical tanks, professionally welded, with corrosion-resistant interior coating and safety valve protection.
Control System
Pressure switch with unloader valve, magnetic starter with overload protection, and dual pressure gauges for pump and system pressure.
Lubrication System
Positive displacement oil pump provides pressurized lubrication to all critical bearings and moving parts.
Cooling System
Integrated intercooler between stages with finned tubing for efficient heat dissipation and improved volumetric efficiency.
Performance Data
5 HP Model
18.1 CFM at 175 PSI, 60 gallon tank, 230V single phase
7.5 HP Model
24.5 CFM at 175 PSI, 80 gallon tank, 230V/460V 3-phase
Oil Capacity
2.5 quarts of Quincy 30 weight compressor oil or equivalent
Belt Specifications
2 B-section V-belts, 50" effective length, adjustable motor base
Maintenance Guide
| Maintenance Item | Frequency | Procedure |
|---|---|---|
| Check Oil Level | Daily | Check sight glass, maintain between marks |
| Drain Tank | Daily | Open drain valve at bottom of tank |
| Change Oil | Every 3 months or 500 hours | Drain while warm, refill with Quincy 30 weight |
| Clean Intake Filter | Monthly | Remove and clean foam filter element |
| Check Belt Tension | Monthly | 1/2" deflection at center of span |
| Inspect Valves | Every 6 months | Remove and clean valve plates |
Troubleshooting Common Issues
- Low Pressure: Worn piston rings, leaking valves, or belt slippage
- Excessive Noise: Worn bearings, loose components, or valve issues
- Overheating: Dirty cooling fins, low oil, or restricted airflow
- Oil in Air Lines: Worn piston rings or overfilled oil sump
- Motor Won't Start: Pressure switch issue, thermal overload, or power problem
- Excessive Cycle Time: Air leaks, worn pump, or undersized motor
Ordering Parts
Common Parts Kits
Overhaul Kit
Complete gasket and seal kit
Valve Repair Kit
Valve plates and gaskets
Bearing Kit
Main and connecting rod bearings
Piston Ring Set
Complete ring set for both stages
Individual Components
Cylinder Liners
Stage 1 and Stage 2 liners
Pressure Switch
175 PSI cut-out switch
Check Valve
Tank check valve assembly
Pulley Set
Motor and pump pulleys
Contact Information
- Quincy Parts Department: 1-800-331-1950
- Technical Support: 1-217-222-7700
- Online Parts: QuincyCompressor.com/parts
- Hours: Mon-Fri 7:00 AM - 5:00 PM CST