System Analysis of Pressure Switch Working Principles, Functions, and Usage Essentials in Heat Pump Systems, Compiled with Technical Principles and Research Findings:
I. Core Working Principles
Pressure Sensing Mechanism
Utilizes elastic elements (spring tubes, diaphragms, bellows) to detect pressure changes. When pressure exceeds/falls below set thresholds, elastic element deformation activates mechanical structures to trigger micro switches.
High-pressure side switches monitor compressor discharge pressure, while low-pressure side switches monitor evaporator return gas pressure, forming a dual safety mechanism.
Circuit Control Logic
During pressure anomalies, switch contacts open/close to directly cut compressor power or trigger alarms, preventing system overpressure operation.
Advanced models employ electronic pressure transmitters outputting 4-20mA signals for controller linkage, enabling precise regulation.
II. Core Functional Features
Safety Protection
High-pressure protection: Prevents compressor overload from condenser blockage or refrigerant overcharge, typical trigger value 2.5-3.5MPa.
Low-pressure protection: Avoids compressor dry-running caused by evaporator frosting or refrigerant leakage, activation range generally 0.1-0.3MPa.
Energy Efficiency Optimization
Automatically adjusts pump/fan speed through pressure feedback to maintain optimal efficiency (e.g., reducing circulation pump frequency at 45℃ floor heating water temperature).
III. Key Parameter Adjustment Methods
Adjustment Item Operation Essentials
High-pressure threshold Clockwise rotation increases trigger pressure, counterclockwise decreases; requires pressure gauge calibration
Low-pressure threshold Set 0.07-0.1MPa below system stabilization pressure (e.g., 0.5MPa setting at normal 0.6MPa pressure)
Differential pressure control Commercial models allow ECU parameter modification to optimize start-stop frequency
IV. Common Faults & Solutions
False Activation Faults
Frequent tripping: Check condenser scaling (cleaning required) or abnormal refrigerant charge (adjust via suction pressure reference).
Pressure display deviation: Calibrate sensors, inspect blocked pressure tubes or aged diaphragms.
Hardware Failure Faults
Contact ablation: Replace micro switches; recommend silver alloy contacts (service life >100,000 cycles).
Sealing failure: Replace O-rings/diaphragms; perform argon leak detection 38 post-welding.
V. Selection & Maintenance Guidelines
Selection Principles
Commercial units prioritize explosion-proof pressure switches with digital displays (e.g., IP67 rating); residential models may use mechanical types.
Refrigerant type affects settings: R32 systems operate at ~20% higher pressure than R410A.
Maintenance Standards
Monthly filter cleaning prevents pressure sensing distortion from contaminants.
Annual electronic leak detection for sealing integrity; open-flame testing prohibited for flammable refrigerant systems.
