Sanhua PSV50AL-S51 High Pressure Switch – 6…32 bar, Automatic Reset, Flare, SPDT

Sanhua PSV50AL-S51 is a single pressure switch connected to the discharge (high pressure) side of the refrigeration circuit. The setting range is 6 … 32 bar, the differential is adjustable between 3 … 15 bar, and it has automatic reset.

Stops the Compressor When Discharge Pressure Rises — The First Line of Defense Against Condenser Blockage

When the condenser gets dirty, the fan stops or the air temperature rises excessively, the discharge pressure climbs rapidly. High pressure does not only reduce efficiency: it stresses seals and brazed joints, causes the compressor to draw excessive current and, in severe cases, leads to mechanical damage.

The pressure switch opens its contact and stops the compressor when the pressure exceeds the set value; when the pressure drops by ΔP, it switches back on automatically. On sites where condenser maintenance is neglected, it is the first safety device that keeps the system running.

⚠️ Safety note: this model has automatic reset. If the pressure equipment safety chain requires manual reset, the PSV50ML-S51 (same range, manual reset) should be chosen.

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

• Model: Sanhua PSV50AL-S51 | Sanhua part no.: 10660012902
• Type: High pressure (HP) · single pressure
• Setting range: 6 … 32 bar
• Differential (ΔP): 3 … 15 bar — separately adjustable
• Reset: automatic (auto)
• PED 2014/68/EU · EN 12263 certification: NOT available on this model

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.