Description
AOVH-20 Fan-Driven Air-Oil Cooler
The AOVH-20 is a larger industrial air-oil cooler designed for hydraulic and lubrication systems that run at higher duty cycles and generate more heat than smaller units can handle. It offers increased cooling surface area and higher airflow, making it a strong fit for medium-to-large power units, gear drives, presses, and heavy industrial machinery that demand stable oil temperatures and long component life.
AOVHR Two-Pass & Relief Bypass Option
The AOVH-20 can be configured as an AOVHR two-pass cooler with an integral relief bypass valve. In the AOVHR configuration, oil flows through the core twice to increase heat transfer, while the built-in bypass valve helps protect against high backpressure during cold starts or when operating with higher viscosity oils.
- Two-pass oil flow: Increases exposure to the cooling core for improved heat rejection.
- Integral relief bypass: Typically offered with 30 psi or 60 psi relief settings (model dependent).
- Typical flow range: For AOVHR-20-2, approximately 4–80 GPM depending on viscosity and operating conditions.
- Shared performance ratings: 300 psi maximum operating pressure and 400°F maximum operating temperature.
AOVH-20 Specifications
- Model: AOVH-20
- Series: AOVH industrial air-cooled oil cooler
- Cooling Type: Fan-driven, air-cooled oil cooler
- Maximum Operating Pressure: 300 psi
- Maximum Operating Temperature: 400°F
- Dimensions (in): A: 11.91, B: 23.81, C: 9.19, D: 18.38, E: 19.49, F: 15.75, G: 17.19, K: 7.00, L: 14.00, M: 10.28, N: 20.56, P: 25.81
- Approximate Net Weight: 110 lb
AOVH / AOVHR Series Overview
The Thermal Transfer AOVH and AOVHR series of industrial air-oil coolers are engineered to provide reliable, efficient, and compact cooling solutions for hydraulic and lubrication systems. These coolers are widely used in injection molding machines, gear drives, hydraulic power units, machine tools, torque converters, and general industrial equipment. The AOVH series offers one-pass flow for standard applications, while the AOVHR series adds a two-pass flow configuration with an integral relief bypass for systems that demand additional protection and enhanced cooling performance.
Key Features & Applications
- High-performance fin-and-tube heat exchanger for demanding hydraulic and lubrication circuits.
- Consistent cooling capacity with fan-driven airflow, independent of ambient conditions.
- Compact cabinet footprint for easy integration into existing equipment layouts.
- Available in one-pass (AOVH) or two-pass (AOVHR) flow configurations.
- Well-suited for hydraulic presses, gearboxes, power units, processing equipment, and industrial automation systems.
- Optional integral bypass for cold-start protection and reduced risk of high pressure drop.
Construction, Ratings & Materials
Pressure & Temperature Ratings
| Maximum Operating Pressure | 300 PSI |
|---|---|
| Maximum Operating Temperature | 400°F |
Standard Materials of Construction
| Tubes | Copper |
|---|---|
| Fins | Aluminum |
| Turbulators | Steel |
| Fan Blade | Aluminum with steel hub |
| Fan Guard | Zinc-plated steel |
| Cabinet | Steel with baked enamel finish |
| Manifolds | Steel |
| Connections | Steel |
Model Weights
| Model | Net Weight (lb) |
|---|---|
| AOVH / AOVHR-5 | 67 |
| AOVH / AOVHR-10 | 78 |
| AOVH / AOVHR-15 | 90 |
| AOVH / AOVHR-20 | 110 |
| AOVH / AOVHR-25 | 157 |
| AOVH / AOVHR-30 | 190 |
| AOVH / AOVHR-35 | 315 |
| AOVH / AOVHR-40 | 350 |
AOVHR Two-Pass Flow Ranges
| Two-Pass Model | Typical Flow Range (GPM) |
|---|---|
| AOVHR-5-2 | 4–50 |
| AOVHR-10-2 | 4–60 |
| AOVHR-15-2 | 4–60 |
| AOVHR-20-2 | 4–80 |
| AOVHR-25-2 | 4–80 |
| AOVHR-30-2 | 4–80 |
| AOVHR-35-2 | 6–80 |
| AOVHR-40-2 | 8–80 |
Installation & Piping Notes
The standard fan rotation is clockwise when viewing the motor shaft. These coolers are generally mounted horizontally with airflow drawn through the finned core. Reference dimensional drawings for mounting hole locations, motor bracket orientation (AOVH-5 and AOVH-10 brackets are rotated 90°), and fan projection details.
AOVH one-pass models route oil from the lower to the upper connection. AOVHR models route oil in and out on the same side, with an internal cap creating the two-pass flow path. Always confirm flow direction before piping.
Lubrication & Motor Bearing Maintenance
Standard motors include factory-lubricated ball bearings. No initial greasing is required. Maintenance intervals vary by duty cycle and environment:
| Operating Condition | Recommended Grease Interval |
|---|---|
| Typical ~5,000 hrs/year | Every 5 years |
| Continuous service | Every 2 years |
| Seasonal/intermittent use | Every 1 year |
| High temperature/dust/vibration | Every 6 months |
Avoid over-lubrication; refer to motor manufacturer guidance.
Viscosity Correction Factors (Cv)
Performance curves assume oil leaving at approximately 50 SSU. Use the following multipliers to estimate cooler performance using various oil viscosities and temperatures:
| Avg. Oil Temp (°F) | Mineral Oil (SAE) | 50/50 EG/Water | ||||
|---|---|---|---|---|---|---|
| SAE 5 | SAE 10 | SAE 20 | SAE 30 | SAE 40 | 50/50 Mix | |
| 100 | 1.14 | 1.22 | 1.35 | 1.58 | 1.77 | 1.11 |
| 150 | 1.01 | 1.05 | 1.11 | 1.21 | 1.31 | 1.02 |
| 200 | 0.99 | 1.00 | 1.01 | 1.08 | 1.10 | 0.96 |
| 250 | 0.95 | 0.98 | 0.99 | 1.00 | 1.00 | 0.95 |
Standard TEFC Motor & Fan Data
| Model | CFM | dB(A) | Motor HP | Volts | Phase | Full Load Amps | Hz | NEMA Frame | RPM | Type | Circuit | Thermal OL | Bearing |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AOVH-5 | 780 | 85 | 1/2 | 115/208-230 | 1 | 7.4 / 3.9-3.7 | 60 | 48 | 3450 | TEFC | C | No | Ball |
| AOVH-10 | 1110 | 85 | 1/2 | 115/208-230 | 1 | 7.4 / 3.9-3.7 | 60 | 48 | 3450 | TEFC | A | No | Ball |
| AOVH-15 | 1590 | 91 | 1/2 | 115/208-230 | 1 | 7.4 / 3.9-3.7 | 60 | 48 | 3450 | TEFC | A | No | Ball |
| AOVH-20 | 2168 | 91 | 1/2 | 115/208-230 | 1 | 7.4 / 3.9-3.7 | 60 | 48 | 3450 | TEFC | C | No | Ball |
| AOVH-25 | 3000 | 81 | 1 | 115/208-230 | 1 | 12.4 / 6.5-6.2 | 60 | 56 | 1725 | TEFC | C | No | Ball |
| AOVH-30 | 4095 | 84 | 1 | 115/208-230 | 1 | 12.4 / 6.5-6.2 | 60 | 56 | 1725 | TEFC | C | No | Ball |
| AOVH-35 | 5921 | 89 | 3 | 208-230/460 | 3 | 9.0-8.6 / 4.3 | 60 | 182T | 1725 | TEFC | D | No | Ball |
| AOVH-40 | 9609 | 91 | 3 | 208-230/460 | 3 | 9.0-8.6 / 4.3 | 60 | 182T | 1725 | TEFC | D | No | Ball |
Explosion-Proof Motor Options
Explosion-proof motor configurations (Class I Group D; Class II Groups F & G) are available for hazardous environments. Always confirm ratings on the motor nameplate.
| Model | CFM | dB(A) | HP | Volts | Phase | Full Load Amps | Hz | NEMA Frame | RPM | Type | Circuit | Thermal OL | Bearing |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| AOVH-5 | 780 | 85 | 1/2 | 115/230 | 1 | 7.4 / 3.7 | 60 | 48 | 3450 | FC | C | Yes | Ball |
| AOVH-10 | 1110 | 85 | 1/2 | 115/230 | 1 | 7.4 / 3.7 | 60 | 48 | 3450 | FC | C | Yes | Ball |
| AOVH-15 | 1590 | 91 | 1/2 | 115/230 | 1 | 7.4 / 3.79 | 60 | 48 | 3450 | FC | C | Yes | Ball |
| AOVH-20 | 2168 | 91 | 1/2 | 115/230 | 1 | 7.4 / 3.79 | 60 | 48 | 3450 | FC | C | Yes | Ball |
| AOVH-25 | 3000 | 81 | 1 | 115/230 | 1 | 12.4 / 6.2 | 60 | 56 | 1725 | FC | C | Yes | Ball |
| AOVH-30 | 4095 | 84 | 1 | 115/230 | 1 | 12.4 / 6.2 | 60 | 56 | 1725 | FC | C | Yes | Ball |
| AOVH-35 | 5921 | 89 | 3 | 230/460 | 3 | 8.6 / 4.3 | 60 | 182T | 1725 | FC | D | No | Ball |
| AOVH-40 | 9609 | 91 | 3 | 230/460 | 3 | 8.6 / 4.3 | 60 | 182T | 1725 | FC | D | No | Ball |
Frequently Asked Questions
AOVH-20 Fan-Driven Air-Oil Cooler
▶️ Question: What types of hydraulic systems are the AOVH-20 best suited for?
Answer: The AOVH-20 is designed for medium-to-large hydraulic power units, lubrication systems, and industrial machinery that generate higher heat loads. It is commonly used in hydraulic presses, processing equipment, injection molding systems, automated manufacturing cells, and gearboxes that operate continuously or under heavier workloads where stable oil temperatures are critical.
▶️ Question: What are the advantages of choosing the AOVHR-20-2 two-pass version?
Answer: The AOVHR-20-2 offers enhanced cooling efficiency by routing oil through the core twice, providing substantially more heat rejection without increasing cabinet size. The built-in relief bypass valve helps prevent excessive system backpressure during cold starts or when oil viscosity spikes. With a typical usable range of about 4–80 GPM, the AOVHR-20-2 is ideal for variable-flow hydraulic systems or applications requiring tighter thermal control.
▶️ Question: What should I know about the AOVH-20’s pressure and temperature limits?
Answer: The AOVH-20 is rated for up to 300 psi maximum operating pressure and 400°F maximum operating temperature. These limits support a wide range of hydraulic and lubrication applications. Maintaining clean oil and appropriate filtration is essential to prevent fouling of the copper tubes and ensure cooling performance remains consistent over time.
▶️ Question: What electrical requirements and noise levels should I consider?
Answer: The AOVH-20 uses a TEFC fan motor (approximately 1/2 HP) typically rated for 115/208–230 V, single-phase, 60 Hz electrical service. Motor noise is in the 90 dB(A) range under full airflow conditions. Confirm the motor nameplate for exact electrical data before installation, and ensure wiring, breaker size, and overload protection comply with local electrical codes.
▶️ Question: How should I install and maintain the AOVH-20 to ensure maximum cooling performance?
Answer: Install the AOVH-20 horizontally with unobstructed airflow. Oil should enter the lower port and exit the upper port, whether installed in a return line or dedicated cooling circuit. Use vibration-isolating hoses where possible, keep the fins clean, and inspect for dust or debris buildup. Proper oil filtration is essential to prevent clogging and maintain heat transfer efficiency. Follow the motor’s lubrication schedule and regularly inspect mounting hardware and electrical connections.
