AUTOOL LM150 Digital Manifold Pressure Tester

Product Introduction

Overview

The AUTOOL LM150 is an intelligent electronic refrigerant group instrument designed as an auxiliary tool for the installation, testing, and maintenance of refrigeration equipment, such as air conditioners and cold storage units. It features double pressure testing, dual temperature testing, digital readout, multi-unit switching, multi-mode functionality, and a built-in refrigerant database.

Constructed with high-strength engineering plastics and a flexible, non-slip silicone design, the instrument is solid and comfortable to hold. It incorporates a 32-bit digital processing unit and a high-precision data acquisition unit, ensuring high data accuracy and stability. The large liquid crystal display with LCD backlight support provides clear and easy-to-read data, facilitating convenient operation. A long-life valve switch and a 1/4-inch standard interface design enhance its durability and versatility.

The instrument can simultaneously measure double pressure (gauge pressure) and dual temperatures. It offers automatic multi-unit pressure conversion and automatic temperature conversion between Celsius and Fahrenheit to meet different needs. Its built-in database of 93 refrigerant pressure-evaporation temperatures aids in calculating subcooling and superheat for direct reading of operating process data. It also performs percentage of vacuum measurement, pressure leak measurement, and records leak time.

International Electrical Symbols

Product Specifications

Built-in 93 kinds of refrigerant NIST: According to American NIST standard

R11, R113, R114, R115, R116, R12, R123, R124, R125, R1270, R13, R134A, R14, R141B, R142B, R143A, R152A, R170, R21, R218, R22, R227EA, R23, R236EA, R245CA, R245FA, R290, R32, R401A, R401B, R401C, R402A, R402B, R403A, R403B, R404A, R405A, R406A, R407A, R407B, R407C, R407D, R407E, R408A, R409A, R409B, R41, R410A, R410B, R411A, R411B, R412A, R413A, R414A, R414B, R415A, R415B, R416A, R417A, R418A, R419A, R420A, R421A, R421B, R422A, R422B, R422C, R422D, R423A, R424A, R425A, R426A, R427A, R428A, R438A, R448A, R449A, R452A, R50, R500, R501, R502, R503, R504, R507A, R508A, R508B, R509A, R600, R600A, R717, R744 (CO2), R1234.

Product Structure

Structure Diagram

The AUTOOL LM150 is a digital manifold pressure tester with a black casing. It features a large LCD screen displaying dual pressure readings (e.g., '25.0 R 134A 25.0', '19.0', '2500 kPa'), temperature readings (e.g., '19.0 °C'), and mode indicators. Below the screen are control buttons labeled MODE, UNIT, ZERO, R-, R+, Power, and °C/°F. At the bottom are two main valve handles (red and blue) and several ports for connecting hoses, including a pressure release valve.

Function Instructions

Refrigerant Filling and Pressure Inspection

• Turn off the blue valve and red valve.
• Power on the instrument. Ensure the LCD displays the pressure test status. If not, press the Mode button to switch modes.
• If temperature probe accessories are connected, real-time temperatures will be displayed.
• Use the R+/R- buttons, Unit button, and °C/°F button to select the tested refrigerant and reading display format.
• When the instrument is turned on, the high and low pressure display areas might show 10 digits. Press and hold the zero button until it returns to zero.
• Connect the instrument to the refrigeration system, paying attention to the direction of refrigerant flow.

Diagram Description: A schematic illustrates the connection of the AUTOOL LM150 to a refrigeration system. The system comprises a Compressor, Condenser, Thermal expansion valve, and Evaporator. The pressure tester is connected via hoses to the high and low-pressure sides of the system. Arrows indicate the direction of refrigerant flow.

• Turn on the refrigerant valve and gently press the pressure release valve to vent air in the connecting hose.
• When the refrigeration system is stopped, turn on the high pressure valve (red valve), fill with a certain amount of refrigerant, and then quickly shut the valve.
• Run the refrigeration system, turn on the low pressure valve (blue valve), and fill the system with refrigerant. Vacuum operation is required if filling initially or completely. Refer to the vacuum operation section.
• After filling, shut the low pressure valve (blue valve) and refrigerant valve. Allow the refrigeration system to run.
• Shut down the refrigeration system, ensure all valves are off, then disconnect the instrument. Do not remove the high pressure valve connection until the pressure drops to a safe level. Turn off the instrument.

NOTE: The filling operation for different equipment or refrigerants may vary. Read relevant specific operation requirements carefully to avoid damage to users or equipment due to improper operation.

LCD Display Description: The instrument can display the corresponding Evaporation Temperature (EV) and Condensation Temperature (CO) during refrigerant pressure testing. When clamp-on temperature probes are connected, the LCD will display real-time temperatures for T1 Sensor and T2 Sensor.

Superheat/Subcooling Display: The instrument can calculate SH (Superheat) and SC (Subcooling) when the refrigerant is preset and temperature probes are connected. °C/°F conversion is available by pressing the MODE button.

Vacuum Operation

• Turn off the blue valve and red valve.
• Power on the instrument. Ensure the LCD displays the vacuum test status. If not, press the Mode button to switch modes.
• Press the Unit button to adjust the reading unit.
• When the instrument is turned on, the high and low pressure display areas might show 10 digits. Press and hold the zero button until it returns to zero.
• Connect the instrument to the refrigeration system, paying attention to the direction of refrigerant flow. Connected clamp-on temperature probes will not affect operation.

Diagram Description: A schematic shows the connection of the instrument to a refrigeration system and a vacuum pump. The vacuum pump is turned on after connecting the blue and red valves. After vacuum operation is complete, the valves are turned off, and the vacuum pump is shut down.

LCD Display Description: The LCD shows a percentage value and pressure in kPa, indicating the vacuum level.

Pressure Leak Test

• Ensure the instrument is powered on with the blue and red valves turned off.
• Press the Mode button to enter the pressure leak test mode. The current pressure value is displayed at the lower right corner of the LCD.
• Press the Run / Stop button to start the leak test.

LCD Display Description: During the leak test, the LCD displays the elapsed time in 'hh:mm' format, the initial pressure value (lower left), the instantaneous pressure value (lower right), and the pressure difference (ΔP) between the initial and instantaneous values.

The time display shows how long the leak test has lasted. All pressure units on the screen are the same. Different pressure units can be switched by pressing the Unit button.

Common Problems

Low Battery Power Supply

The instrument displays a low power sign when the battery is insufficient. Replace the battery as required to avoid affecting normal use.

Damaged Refrigerant Hose or Valve Stem

Check pipe fittings and hoses before testing. Replace any damaged parts immediately to prevent improper use or accidents.

Failure of Refrigerant Filling

Ensure the valve core in the refrigerant inlet of the refrigeration system is correctly handled. Connect one hose terminal with a core to the system and the other without a core to the instrument.

Potential Leak Points

• Hose terminals have nylon pads with a limited lifespan; overuse can cause defects and leakage.
• The instrument's refrigerant inlet has a port with a valve core used to vent air after connecting refrigerant.
• This port is equipped with a copper plug screw that requires tightening before or after each operation.
• Regularly check the refrigeration system's pipes and connectors for leaks.

Glossary

Saturation

The state of saturation is the coexistence of a refrigerant in a liquid and gas state.

Condensation Temperature and Evaporation Temperature

Condensation temperature: In the condenser, the refrigerant is condensed by the high-temperature gaseous refrigerant to the temperature of the liquid refrigerant, which is the saturation temperature under the condensing pressure.

Evaporation temperature: In the evaporator, the refrigerant evaporates from the liquid refrigerant to the temperature of the gaseous refrigerant, which is the saturation temperature under the evaporation pressure.

Degree of Subcooling and Superheat

Subcooling: Condensing temperature - condensing outlet temperature.

Superheat: Evaporation outlet temperature - evaporation temperature.

Lower subcooling can improve the refrigeration capacity of the system. Adding a subcooling circuit and economizer increases subcooling for refrigerant enhancement.

The degree of expansion of the expansion valve (refrigerant charge) affects the degree of superheat. Greater superheat indicates a smaller opening of the expansion valve (less refrigerant charge).

Sensible Heat and Latent Heat

The amount of heat required to raise water temperature from 0 to 100 degrees is sensible heat. When water is heated to 100 degrees and becomes water vapor while the temperature remains 100 degrees, the heat required for this process is called latent heat.

Gauge Pressure and Absolute Pressure

Gauge pressure: Refers to pipeline pressure measured by gauges (pressure, vacuum, U-shaped tubes), also known as relative pressure. It starts from atmospheric pressure (symbol Pg).

Absolute pressure: The pressure acting directly on the surface of a container or object. It uses absolute vacuum as a starting point (symbol PABS). Absolute pressure = atmospheric pressure + gauge pressure.

At atmospheric pressure, gauge pressure is 0 and absolute pressure is 1.013bar.

Dry Bulb Temperature, Wet Bulb Temperature and Black Ball Temperature

Dry bulb temperature: The temperature measured by ordinary thermometers.

Wet bulb temperature: A wet cloth wrapped around a thermometer causes a temperature drop due to water evaporation. This temperature is the wet-bulb temperature.

A device with both dry and wet bulb thermometers is a dry humidimeter, used to measure relative humidity.

Black ball temperature: Also called actual temperature, it indicates sensory temperature when combined with radiant and convective heat in a radiant environment. It is generally higher than ambient air temperature.

Relative Humidity and Absolute Humidity

Absolute humidity: The mass of water vapor per unit volume of air, representing atmospheric dryness and humidity. Usually expressed in grams of water vapor per cubic meter of air.

Relative humidity: The ratio of actual water vapor density in air to the saturated water vapor density at the same temperature.

The degree of dryness and humidity is related to the saturation of water vapor, not directly to its absolute amount.

COP and EER

EER (Energy Efficiency Ratio): The ratio of cooling capacity to effective input power during an air conditioner's cooling operation under rated conditions, expressed in W/W.

COP (Coefficient of Performance): The ratio of heating capacity to effective input power during an air conditioner's heat pump heating operation under rated conditions, expressed in W/W.

Maintenance Service

AUTOOL products are made from durable materials with a rigorous production process, undergoing extensive testing to ensure excellent quality and performance.

Maintenance

To maintain product performance and appearance, follow these guidelines:

• Be careful not to rub the product against rough surfaces, especially the sheet metal housing.
• Regularly check and tighten product parts. Ensure safe operation by promptly tightening any loose connections.
• External and internal parts exposed to chemical media should undergo anti-corrosion treatment (rust removal, painting) to improve resistance and extend service life.
• Comply with safe operating procedures and avoid overloading the equipment. Safety guards are complete and reliable.
• Address unsafe factors promptly. Inspect circuit parts and replace aging wires.
• Adjust clearances and replace worn or broken parts. Avoid contact with corrosive liquids.
• When not in use, store the product in a dry place, away from hot, humid, or non-ventilated areas.

Warranty

A three-year warranty is provided for the main unit from the date of receipt, and all included accessories are covered by a one-year warranty.

Warranty Access

• Product repair or replacement is determined by the actual breakdown situation.
• AUTOOL guarantees the use of brand-new components, accessories, or devices for repairs or replacements.
• If the product fails within 90 days of receipt, the buyer must provide video and pictures. AUTOOL will cover shipping costs and provide accessories free of charge. For failures after 90 days, the customer bears appropriate costs, while AUTOOL provides parts for free replacement.

These conditions below shall not be in warranty range:

• Products not purchased through official or authorized channels.
• Product breakdown due to failure to follow product instructions for use or maintenance.

AUTOOL prides itself on superb design and excellent service, offering further support and services.

Disclaimer

All information, illustrations, and specifications in this manual are subject to modification by AUTOOL without prior notice. Physical appearance and color may differ from the manual; refer to the actual product. While efforts have been made to ensure accuracy, inaccuracies may exist. Contact your dealer or AUTOOL after-service center for clarification. AUTOOL is not responsible for consequences arising from misunderstandings.

Return & Exchange Service

Return & Exchange

• If unsatisfied with AUTOOL products purchased from authorized platforms or dealers, returns are accepted within seven days of receipt, or exchanges for products of the same value within 30 days of delivery.
• Returned and exchanged products must be in fully saleable condition with proof of purchase, all accessories, and original packaging.
• AUTOOL will inspect returned items for eligibility. Items not passing inspection will be returned without a refund.
• Exchanges can be processed through the customer service center or authorized distributors. If difficulties arise with returns or exchanges, contact AUTOOL Customer Service.