AUTOOL Im 120 DIGITAL MANIFOLD GAUGE

1. Overview

The AUTOOL Im 120 is an intelligent electronic refrigerant group instrument designed as an auxiliary tool for the installation, testing, and maintenance of refrigeration equipment, including air conditioners and cold storage. It features double pressure and 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 durable and comfortable to hold. It incorporates a 32-bit digital processing unit and a high-precision data acquisition unit for stable and accurate data. The large-size liquid crystal display with LCD backlight ensures clear and easy-to-read data, facilitating convenient operation. It utilizes a long-life valve switch and a standard 1/4-inch interface for versatility and durability.

The instrument can simultaneously measure double pressure (gauge pressure) and dual temperatures. It offers automatic multi-unit pressure conversion and automatic conversion between Celsius and Fahrenheit to meet different needs. A built-in database of 89 refrigerants allows for automatic conversion of pressure to evaporation temperature. It can also calculate subcooling and superheat, providing direct readings of operating process data. Additional functions include percentage of vacuum measurement, pressure leak measurement, and leak time speed recording, making it a comprehensive and accurate tool for refrigeration tasks.

2. Safety Rules and Precautions

This manual contains important instructions and warnings for the safe operation and maintenance of the instrument. Failure to use the meter as described in this manual may result in damage to the instrument. This instrument strictly follows IEC/EN61010-1 safety standards for design and production.

3. International Electrical Symbols

4. Product Specifications

Pressure Test

Pressure test type: Gauge pressure

Pressure test units: Kpa, Mpa, bar, inHg, PSI

Pressure test range: 0 Kpa - 6000 Kpa

Pressure test resolution: 1 Kpa

Pressure test accuracy: +/- 0.5% (FS) + 5dgt

Pressure overload limit: 10000 Kpa (10 Mpa; 100 bar)

Vacuum Test

Vacuum test type: Relative vacuum

Vacuum test units: Kpa, Mpa, bar, inHg, PSI

Vacuum test range: -101 Kpa - 0 Kpa

Vacuum test resolution: 1 Kpa

Temperature Test

Temperature test units: °C (Celsius), °F (Fahrenheit)

Temperature test range: -40°C to 150°C (-40°F to 302°F)

Temperature test resolution:

• 0.1°C (-40°C to 99.9°C), 1°C (100°C to 150°C)
• 0.1°F (-40°F to 99.9°F), 1°F (100°F to 302°F)

Temperature test accuracy: +/- 0.5 °C + 2dgt / +/- 0.9 °F + 2dgt

Refrigerants: Built-in 89 kinds of refrigerant NIST (According to American NIST standard)

5. Product Icon and Description

Refrigerant List: 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, R4240, R425A, R426A, R427A, R428A, R50, R500, R501, R502, R503, R504, R744 (CO2), R507A, R508A, R508B, R509A, R600, R600A, R717, R1234.

Power Supply: 4 X 1.5V (SIZE.AA/LR6)

Dimensions: 170*110*50mm

Weight: 950g

Product Components:

• 1, 2: Clamp-on temperature probe sockets
• 3: LCD display
• 4: Run/Stop button (In Leak Test Mode, Test Control Button)
• 5: Function button (Test function mode switch button)
• 6: R+/R- Refrigerant Type Selection Buttons (Switch to select different types of working refrigerants)
• 7: Unit button (Pressure unit switch button)
• 8: °C/°F button (Temperature unit switch button)
• 9: Zero button (Pressure display zero button)
• 10: Backlit button
• 11: Power button
• 12: Refrigerant observation window
• 13: Low pressure valve
• 14: High pressure valve
• 15: 1/4 inch low pressure inlet
• 16: 1/4 inch high pressure inlet
• 17: Pressure release valve
• 18: Refrigerant inlet/vacuum pump inlet

6. Function Instructions

6-1. Refrigerant Filling and Pressure Inspection

A. Turn off the blue and red valves.

B. Power on the instrument. Ensure the LCD displays the pressure test status. If not, press the Function button to switch modes.

C. If temperature probe accessories are connected, the real-time temperature will be displayed. Otherwise, no temperature will be shown.

D. Use the R+/R- buttons, Unit button, and °C/°F button to select the tested refrigerant and desired display units.

E. When the instrument is first turned on, the high and low pressure display areas might show initial readings. Press and hold the Zero button until the display returns to zero.

F. Connect the instrument to the refrigeration system as shown in the diagram below, paying close attention to the direction of refrigerant flow.

Refrigeration System Diagram Description:

The diagram illustrates a refrigeration cycle including a compressor, condenser, thermal expansion valve, and evaporator. Arrows indicate the direction of refrigerant flow. The AUTOOL Im 120 instrument is shown connected to the system, with valves for high and low pressure, and inlets for refrigerant/vacuum pump and temperature probes.

G. Turn on the refrigerant valve and gently press the pressure release valve to vent air from the connecting hose.

H. When the refrigeration system is stopped, turn on the high pressure valve (red valve), fill with the required amount of refrigerant, and then quickly shut the valve.

I. 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.

J. After filling is complete, shut the low pressure valve (blue valve) and the refrigerant valve. Allow the refrigeration system to run.

K. Shut down the refrigeration system. Ensure all valves are turned off before disconnecting the instrument from the system. Do not disconnect the high pressure valve connection until the pressure drops to a safe level. Then, turn off the instrument.

Note: The filling operation for different equipment or refrigerants may vary. Carefully read specific operation requirements to avoid damage due to improper operation.

The instrument can display the corresponding Evaporation Temperature (EV) and Condensation Temperature (CO) during refrigerant pressure testing.

If clamp-on temperature probes are connected, the LCD will display the real-time temperature at the T1 and T2 Sensor locations, provided they are properly connected to the refrigeration pipes.

The instrument can calculate Superheat (SH) and Subcooling (SC) when the tested refrigerant is preset and clamp-on temperature probes are correctly connected.

6-2. Vacuum Operation

A. Turn off the blue and red valves.

B. Power on the instrument. Ensure the LCD displays the vacuum test status. If not, press the Function button to switch modes.

C. Press the Unit button to adjust the reading unit.

D. When the instrument is first turned on, the high and low pressure display areas might show initial readings. Press and hold the Zero button until the display returns to zero.

E. Connect the instrument to the refrigeration system as shown in the diagram below, paying close attention to the direction of refrigerant flow. Connected clamp-on temperature probes will not affect this operation.

Vacuum Operation Diagram Description:

The diagram illustrates a refrigeration system (condenser, compressor, evaporator) connected to a vacuum pump. Arrows indicate refrigerant flow. The AUTOOL Im 120 instrument is shown connected, with valves and inlets.

F. Turn on the blue and red valves, and start the vacuum pump.

G. After vacuum operation is complete, turn off the blue and red valves, then shut the vacuum pump. The pressure leak test mode can now be used to check for system leakage (refer to 6-3. Pressure Leak Test).

6-3. Pressure Leak Test

A. The instrument is powered on with the blue and red valves turned off.

B. Press the Function button to enter the pressure leak test mode. The current pressure value is displayed at the lower right corner of the LCD.

C. Press the Run/Stop button to start the leak test.

Leak Test Display Description:

During the leak test, the display shows:

• The lower left corner: Initial pressure value.
• The lower right corner: Instantaneous pressure value.
• The "ΔP" display area: The difference between the initial and instantaneous pressure values.
• The time display area: Duration of the leak test in Hour:Minute (HH:MM) format.

All pressure units on the screen are the same. You can switch between different pressure units by pressing the Unit button.

7. Common Problems

7-1. 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.

7-2. Damaged Refrigerant Hose or Valve Stem

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

7-3. Failure of Refrigerant Filling

The refrigerant inlet of the refrigeration system has a valve core. When connecting the instrument, ensure one hose terminal with a core connects to the system, and the other terminal without a core connects to the instrument.

7-4. Potential Leak Points

• Hose terminals use nylon pads with limited lifespan. Overuse can lead to defects and leakage.
• The instrument's refrigerant inlet (middle port) has a valve core used to vent air from the hoses after connecting refrigerant.

The port is equipped with a copper plug screw, which must be tightened every time before or after operation. Check the refrigeration system's pipes and connectors.

8. 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 from a high-temperature gas to a liquid at the saturation temperature under condensing pressure.

Evaporation temperature: In the evaporator, the refrigerant evaporates from a liquid to a gas at the saturation temperature under 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 can increase subcooling for better refrigerant performance.

Degree of Superheat Impact

The degree of expansion valve opening (refrigerant charge) affects superheat. Greater superheat implies a smaller expansion valve opening, indicating less refrigerant charge.

Sensible Heat and Latent Heat

Sensible heat: The heat required to raise the temperature of a substance (e.g., water from 0 to 100 degrees Celsius).

Latent heat: The heat required for a phase change at a constant temperature (e.g., water turning into vapor at 100 degrees Celsius).

Gauge Pressure and Absolute Pressure

Gauge pressure (Pg): Pressure measured relative to atmospheric pressure, often indicated by pressure gauges or vacuum gauges.

Absolute pressure (PABS): Pressure measured from absolute vacuum. It is calculated as atmospheric pressure + gauge pressure.

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

Dry Bulb Temperature, Wet Bulb Temperature, and Black Ball Temperature

Dry bulb temperature: The temperature measured by an ordinary thermometer.

Wet bulb temperature: The temperature indicated by a thermometer with a wet cloth wrapped around it, due to evaporative cooling.

Black ball temperature (Actual temperature): The perceived temperature combining radiant heat and convective heat in an environment. It is generally higher than ambient temperature.

A device measuring both dry and wet bulb temperatures is called a dry humidimeter, used to measure relative humidity.

Relative Humidity and Absolute Humidity

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

Relative humidity: The ratio of the actual water vapor density in the air to the saturated water vapor density at the same temperature, expressed as a percentage.

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

COP and EER

EER (Energy Efficiency Ratio): The ratio of cooling capacity to effective input power during air conditioner cooling operation under specified conditions (W/W).

COP (Coefficient of Performance): The ratio of heating capacity to effective input power during air-conditioning heat pump heating operation under specified conditions (W/W).