Refrigeration
Excellent Compressor GS91AZ 1/3 HP R134a 9.1cc
Mbsmpro, Compressor, GS91AZ, 1/3 HP, R134a, 9.1 cc, 220V 50Hz, LBP, Cooling & Freezing
In the demanding world of domestic and light commercial refrigeration, reliability and heat-exchange efficiency are the primary benchmarks for selecting a hermetic compressor. The Excellent Compressor GS91AZ has established itself as a robust solution for engineers and technicians looking for a durable replacement in various cooling appliances. Designed specifically for Low Back Pressure (LBP) applications, this reciprocating unit balances power and energy savings, making it a staple in the high-performance cooling sector.
The core strength of the GS91AZ lies in its internal construction. Unlike cheaper alternatives that might use aluminum-clad wiring, this model is built with 100% high-grade copper windings. This structural choice ensures superior thermal conductivity and a longer lifespan, significantly reducing the risk of winding burnout during prolonged operation or high ambient temperature conditions. With a displacement of 9.1 cc, it provides the necessary torque to maintain stable pressures in medium-to-large-sized household refrigerators and vertical freezers.
Technical Specifications and Performance Data
The following table provides a detailed breakdown of the characteristic features of the GS91AZ model, ensuring field workers have the precise data required for installation and repair.
| Parameter | Technical Specification |
| Model | GS91AZ |
| Utilization (LBP/MBP/HBP) | LBP (Low Back Pressure) |
| Primary Domain | Freezing and Deep Cooling |
| Oil Type and Quantity | POE (Polyolester) / 280 ml – 300 ml |
| Horsepower (HP) | 1/3 HP |
| Refrigerant Type | R134a |
| Power Supply | 220V – 240V / 50Hz |
| Cooling Capacity (BTU/h) | Approx. 780 – 820 BTU/h (at ASHRAE LBP) |
| Motor Type | RSIR (Resistance Start – Induction Run) |
| Displacement | 9.1 cc |
| Winding Material | 100% High-Conductivity Copper |
| Pressure Charge | Suction: 0.5 to 1.5 bar (Application Dependent) |
| Capillary Tube Size | 0.036″ to 0.042″ (Length varies by appliance) |
| Compatible Appliances | Large 2-door Fridges, Chest Freezers, Water Coolers |
| Function Temperature | -35°C to -10°C |
| Cooling Method | Static or Fan Assisted (depending on housing) |
| Market Segment | Professional / Light Commercial |
| Operational Amperage | 1.1 A to 1.4 A |
| LRA (Locked Rotor Amps) | 14.5 A to 16 A |
| Starting Relay Type | PTC Relay or Current Relay |
| Capacitor Requirement | Usually none (RSIR), optional start cap for high torque |
Compressor Replacement Cross-Reference
Choosing the right replacement is critical for system balance. Below are verified equivalents based on displacement and gas type.
5 Compressor Replacements (Same R134a Gas):
- Secop (Danfoss): GL90AA (9.09 cc)
- Embraco: FFI10HBK / FF10HBK
- ZMC: GM90AZ
- Tecumseh: AE1390Y
- Wanbao / Huayi: QD91
5 Compressor Replacements (Alternative Refrigerants – System Flush Required):
- R600a Equivalent: NLE9KK (Secop)
- R600a Equivalent: EMT2125GK (Embraco)
- R290 Equivalent: NEK2134U (Embraco – High Pressure adjustment required)
- R1234yf Equivalent: YF9.0GY
- R404A Equivalent: ML90FB (LBP specific conversion)
Comparative Analysis: GS91AZ vs. Industry Standards
To understand the positioning of the GS91AZ, it is essential to compare it with leading industry models of similar displacement.
| Model | Displacement | Refrigerant | COP | Typical HP |
| Excellent GS91AZ | 9.1 cc | R134a | 1.25 | 1/3 HP |
| Secop GL90AA | 9.09 cc | R134a | 1.32 | 1/4 HP+ |
| Embraco FF8.5HBK | 7.95 cc | R134a | 1.28 | 1/4 HP |
| ZMC GM90AZ | 9.0 cc | R134a | 1.20 | 1/3 HP |
While the GS91AZ maintains a slightly lower COP (Coefficient of Performance) of 1.25 compared to some high-end Secop models, it offers a more aggressive displacement-to-price-performance ratio in the 1/3 HP segment. This makes it an ideal choice for regions with fluctuating voltages where rugged copper windings provide a crucial safety margin against electrical stress.
Electrical Schema and Wiring Configuration
For a standard RSIR (Resistance Start Induction Run) setup, the electrical connection is straightforward but requires precision. The compressor features three terminals: Common (C), Start (S), and Run (R).
- Protector (Overload): Connected directly to the Common (C) terminal.
- Relay (PTC/Current): Plugged onto the Run (R) and Start (S) terminals
- Power Input:
- Line (L) goes to the Thermal Overload Protector.
- Neutral (N) goes to the main terminal of the Relay (Run side).
Note: In cases where a start capacitor is required for high-torque starts, it is wired in series with the start terminal through the relay contacts.
Installation Advice and Best Practices
- Vacuuming: Always perform a deep vacuum (at least 500 microns) to remove moisture. R134a systems are highly sensitive to humidity, which can lead to acid formation in the POE oil.
- Oil Maintenance: If a system has suffered a burnout, the condenser and evaporator must be flushed. Residual acid will contaminate the fresh POE oil in the new GS91AZ, leading to premature failure.
- Filter Drier: Never reuse a filter drier. Always install a new XH-9 or equivalent drier to protect the 9.1 cc displacement valve plate from debris.
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Excerpt: The Excellent Compressor GS91AZ has established itself as a robust solution for engineers and technicians looking for a durable replacement in various cooling appliances. Designed specifically for Low Back Pressure (LBP) applications, this reciprocating unit balances power and energy savings, making it a staple in the high-performance refrigeration and cooling sector.
