Sanhua PSV01AL-S01 Low Pressure Switch – −0.5…7 bar, Automatic Reset, Flare, SPDT

Sanhua PSV01AL-S01 is a single pressure switch connected to the suction (low pressure) side of the refrigeration circuit. The setting range is −0.5 … 7 bar, the differential is adjustable between 0.7 … 5 bar, and it has automatic reset.

Stops the Compressor When Suction Pressure Drops — Prevents Running into Vacuum and Winding Burnout

When the suction pressure drops due to a refrigerant leak, a clogged filter drier or a closed valve, the compressor starts running into vacuum. No cooling takes place in vacuum but, worse still, the refrigerant flow that cools the motor winding is cut off — the winding heats up and burns out. In addition, a circuit that falls into vacuum draws in moisture from outside, which means acid and icing.

The pressure switch opens its contact and stops the compressor when the pressure falls below the set value. When the pressure returns to normal, it closes again automatically.

The low pressure switch is also the control element of the pump-down cycle: it is the switch that stops the compressor once the suction side has been pumped down after the solenoid valve closes.

Technical Specifications (Official Sanhua Datasheet DS-PSV-EN-R2305)

• Model: Sanhua PSV01AL-S01 | Sanhua part no.: 10660012102
• Type: Low pressure (LP) · single pressure
• Setting range: −0.5 … 7 bar
• Differential (ΔP): 0.7 … 5 bar — separately adjustable
• Reset: automatic (auto)
• PED 2014/68/EU · EN 12263 certification: YES

Electrical and Ambient Ratings (Common)

• Contact: SPDT (single pole, double throw) — snap-action micro switch
• Contact load: AC1 400 V / 16 A · AC3 400 V / 16 A · AC15 400 V / 10 A · DC 24 V / 16 A
• Connection: 7/16-20 UNF flare (fits 1/4" and 6 mm tube)
• Protection class: IP30 (IP44 optional)
• Medium temperature: −40 … +120 °C | Ambient temperature: −30 … +65 °C
• Compatible refrigerants: R22 · R407A/F · R448A/R449A · R452A · R513A · R450A · R410A

• 🔑 Reading the code: PSV | 01/50 | A | L | -S01/-S51 → the number indicates the pressure family (01 low, 50 high), A automatic reset (M would be manual), L flare connection. The full technical card is in the 2nd image.
• 🔧 What automatic reset means: when the pressure returns to the safe range, the contact closes by itself; no manual reset is needed. In applications requiring a safety chain, the manual reset (M) version is preferred.
• 🔧 The differential (ΔP) is adjusted separately. The set pressure determines the point at which the switch opens, and ΔP the point at which it closes again. If ΔP is set too narrow, the unit cycles on and off constantly (short cycling); if set too wide, the system stays off longer than necessary.
• ⚠️ R32, R717 (ammonia), R290 (propane) and R1234yf require separate model approval from Sanhua; consult the manufacturer before using this model with those refrigerants.
• Installation: connected to the line with a capillary tube; the body is fixed away from vibration and in an upright position. Hold the body with a wrench when tightening the flare nut.