Technical data, tools and notes for refrigeration and electronics technicians.

Excellent Compressor GS91AZ 1/3 HP R134a 9.1cc mbsmpro
18, Jan 2026
Excellent Compressor GS91AZ 1/3 HP R134a 9.1cc
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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.

ParameterTechnical Specification
ModelGS91AZ
Utilization (LBP/MBP/HBP)LBP (Low Back Pressure)
Primary DomainFreezing and Deep Cooling
Oil Type and QuantityPOE (Polyolester) / 280 ml – 300 ml
Horsepower (HP)1/3 HP
Refrigerant TypeR134a
Power Supply220V – 240V / 50Hz
Cooling Capacity (BTU/h)Approx. 780 – 820 BTU/h (at ASHRAE LBP)
Motor TypeRSIR (Resistance Start – Induction Run)
Displacement9.1 cc
Winding Material100% High-Conductivity Copper
Pressure ChargeSuction: 0.5 to 1.5 bar (Application Dependent)
Capillary Tube Size0.036″ to 0.042″ (Length varies by appliance)
Compatible AppliancesLarge 2-door Fridges, Chest Freezers, Water Coolers
Function Temperature-35°C to -10°C
Cooling MethodStatic or Fan Assisted (depending on housing)
Market SegmentProfessional / Light Commercial
Operational Amperage1.1 A to 1.4 A
LRA (Locked Rotor Amps)14.5 A to 16 A
Starting Relay TypePTC Relay or Current Relay
Capacitor RequirementUsually 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):

  1. Secop (Danfoss): GL90AA (9.09 cc)
  2. Embraco: FFI10HBK / FF10HBK
  3. ZMC: GM90AZ
  4. Tecumseh: AE1390Y
  5. Wanbao / Huayi: QD91

5 Compressor Replacements (Alternative Refrigerants – System Flush Required):

  1. R600a Equivalent: NLE9KK (Secop)
  2. R600a Equivalent: EMT2125GK (Embraco)
  3. R290 Equivalent: NEK2134U (Embraco – High Pressure adjustment required)
  4. R1234yf Equivalent: YF9.0GY
  5. 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.

ModelDisplacementRefrigerantCOPTypical HP
Excellent GS91AZ9.1 ccR134a1.251/3 HP
Secop GL90AA9.09 ccR134a1.321/4 HP+
Embraco FF8.5HBK7.95 ccR134a1.281/4 HP
ZMC GM90AZ9.0 ccR134a1.201/3 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).

  1. Protector (Overload): Connected directly to the Common (C) terminal.
  2. Relay (PTC/Current): Plugged onto the Run (R) and Start (S) terminals
  3. 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.

Focus Keyphrase: Excellent Compressor GS91AZ 1/3 HP R134a 9.1cc High Performance Refrigeration Unit

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Meta Description: Discover the technical specifications of the Excellent Compressor GS91AZ. A 1/3 HP, R134a reciprocating unit with 9.1cc displacement and copper windings for superior cooling.

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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.

Excellent Compressor GS91AZ 1/3 HP R134a 9.1cc mbsmpro
Excellent Compressor GS91AZ 1/3 HP R134a 9.1cc mbsmpro

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