Sanhua YCQC02L18 Pressure Sensor (Transducer) – 4-20 mA Output, −1…12 Bar, 7/16" Flare, Packard

Sanhua YCQC02L18 is a pressure sensor (transducer) that continuously measures pressure in refrigeration, air conditioning and heat pump circuits and converts it into a 4-20 mA current signal. Its measuring range is −1 … 12 bar; since it also reads negative values, it can also be used for vacuum monitoring.

4-20 mA Current Loop: No Signal Degradation over Long Cables and in Noisy Environments

The distinguishing feature of this sensor is its current output. The current loop signal is unaffected by cable length and voltage drop in the cable — while long cables shift the measurement in voltage-output (0.5-4.5 V) sensors, the 4-20 mA signal reaches the panel unchanged.

Its second advantage is fault diagnosis: a healthy loop delivers 4 mA even at the lowest pressure. If the cable breaks or the sensor dies, the current drops to 0 mAand the controller can distinguish this as "no signal". With a voltage-output sensor, 0 V can mean both "lowest pressure" and "fault".

🔑 Do not confuse with YCQB: The YCQB series in our catalog has 0.5-4.5 V ratiometric voltage output and a white plastic body. YCQC , on the other hand, has 4-20 mA current output, a stainless steel body and a cable connector. Choose according to the signal your controller expects.

Technical Specifications (Official Sanhua Datasheet)

• Model: Sanhua YCQC02L18 | Sanhua part no.: 10185017102
• Measuring Range: −1 … 12 bar (including vacuum)
• Output Signal: 4 – 20 mA (current loop)
• Power Supply: 10 – 30 V DC
• Accuracy: ±0.8 %FS (relative to full scale)
• Max. Working Pressure: 52.5 bar
• Refrigerant Temperature: −40 … +80 °C | Humidity: 0-95% RH
• Connection: 7/16-20 UNF-2B flare — in the code, the letter L indicates flare and the letter H indicates 1/4" brazed
• Electrical Connector: Packard (with cable) | Body: stainless steel
• Protection Class: IP65 / IP66
• Voltage Dependence: < 0.05% FS / 10 V | Current Limit: 28 mA | Insulation Resistance: ≥100 MΩ
• Compatible Refrigerants: R32 and other HFC / HFO refrigerants
• Certificates: EMC and PED directive declarations

• 🔧 Code reading: YCQ = pressure transmitter · C = current output · 02 = pressure class · L = flare connection.
• 🔧 Installation: Preferably fitted on a vertical axis with the sensor facing upward; this way oil and liquid do not accumulate in the body.
• ⚠️ Verify the input type of your controller. This sensor requires a current (mA) input. It cannot be connected directly to a controller with a voltage (V) input — either a controller with a suitable input or a mA→V converter is required.
• Do not overtighten the flare connection; applying a drop of refrigeration oil to the seal surface improves sealing.
• ℹ️ About the image: The photo is the manufacturer's YCQC series image; another code of the same series may be printed on the body. The product is the −1…12 bar / 4-20 mA model specified in the code.