Yes, condensation in electrical enclosures during the rainy season can continuously interfere with vacuum sensors through three layers—wiring, circuit boards, and pressure-conducting lines—causing distorted readings, false alarms, and even probe damage.

I. Condensation and electrical leakage at terminal blocks result in erratic signal drift.

Vacuum transmitters output a weak 4–20 mA analog signal with very low insulation margin:

Condensation inside the enclosure forms a conductive water film on terminal blocks and shielded cable connectors, causing micro-leaks between signal wires, ground wires, and the shielding layer, resulting in continuous fluctuations in negative pressure readings;

Moisture corrodes copper terminals, forming verdigris, and contact resistance constantly changes with humidity, leading to significant deviations in vacuum readings from one measurement to the next;

In severe cases, signal wires short-circuit, causing the controller to directly report a vacuum probe failure and the unit to interrupt the concentration process.

II. Condensation on the Transmitter Mainboard, Leading to Failure of Pressure Reference and Temperature Compensation

Vacuum sensors contain built-in precision data acquisition circuit boards, temperature compensation resistors, and processing chips:

Condensation adhering to the surfaces of these components reduces the circuit board’s insulation performance, causing the pressure calibration reference to drift; even after on-site recalibration, the reading drifts again within a few hours;

A humid environment damages the temperature compensation circuit, significantly amplifying vacuum errors when evaporation temperatures change;

Long-term condensation corrodes the copper foil in the circuitry, leading to open circuits and chip breakdown, rendering the sensor completely inoperable.

III. Water Accumulation in the Pressure-Transmitting Tubing, Resulting in Complete Distortion of Negative Pressure Transmission

When the vacuum pressure-transmitting tubing enters the electrical control cabinet, condensation inside the cabinet flows back along the tubing into the transmitter’s diaphragm chamber:

The accumulated water presses against the sensing diaphragm, preventing accurate detection of the chamber’s negative pressure; readings either freeze or remain persistently elevated;

The water seals off the tubing, preventing the transmission of non-condensable gas and steam pressure; gas leaks from manholes and fluctuations in steam production go completely undetected, leading to uncontrolled vacuum without warning.

IV. Moisture in PLC Analog Channels Causes System-Wide Signal Disruption

Condensation in the electrical control cabinet affects more than just the vacuum probe:

The insulation resistance of the PLC’s analog input ports decreases, causing simultaneous interference with all sensor signals—including temperature, liquid level, and conductivity;

Since the staged concentration logic relies on vacuum levels to regulate heating and feed, distorted vacuum readings can trigger a chain reaction of operational abnormalities:

The system mistakenly judges the vacuum to be sufficient and continues heating, while the actual negative pressure is low and the boiling point rises, exacerbating foaming and material carryover;

Frequent false low-vacuum alarms cause the unit to repeatedly reduce load and cycle feed on and off, resulting in significant level fluctuations that accelerate salt scale buildup and blockage in the plate heat exchanger.

V. Vicious Cycle Logic in the Rainy Season Environment

Outdoor units experience large diurnal temperature fluctuations, and the electrical cabinets are sealed and poorly ventilated. During the day, rising temperatures cause water vapor to evaporate; at night, cooling temperatures cause condensation and water accumulation, resulting in chronically high humidity and saturation inside the cabinet;

Vacuum probes and wiring are continuously exposed to a humid environment, and drift issues will not resolve on their own; faults become more frequent as rainy weather sets in.