Sanhua PSV15AML-S51 Dual Pressure Switch – LP −0.5~7 Bar Automatic / HP 6~32 Bar MANUAL Reset, 7/16" Flare

The Sanhua PSV15AML-S51 is a dual pressure switch that protects the compressor against both excessively low suction pressure and excessively high discharge pressure in refrigeration and air conditioning circuits. A single housing contains two independent pressure units.

High Pressure Reset Is MANUAL: The Compressor Does Not Restart by Itself

The distinguishing feature of this model is its reset behavior:

• Low pressure (LP) → AUTOMATIC reset: when suction pressure returns to normal, the compressor restarts by itself.
• High pressure (HP) → MANUAL reset: when discharge pressure exceeds the limit, the contact opens and does not close until reset by hand.

A high pressure trip is always a sign of a fault (dirty condenser, stopped fan, overcharge, blocked line). While an automatic-reset device would put the compressor into the same fault again and again, manual reset calls the service technician to the site and prevents the compressor from tripping repeatedly.

🔎 Which model should I choose? A version with the same pressure range and automatic reset on both sides is also available in our catalog. If you want the circuit to return to operation without human intervention, choose the automatic-reset model; if you want a high pressure fault to be noticed and investigated, choose this manual-reset model. For higher-pressure circuits, see the PSV16 (HP 8~42 bar) version.

Technical Specifications (Official Sanhua Datasheet)

• Model: Sanhua PSV15AML-S51 | Sanhua part no: 10660012202
• Low Pressure (LP): setting −0.5 … 7 bar · differential 0.7 … 5 bar (adjustable) · reset automatic
• High Pressure (HP): setting 6 … 32 bar · differential 4 bar (fixed) · reset MANUAL
• Contact: SPDT | Contact Load: AC1 16 A / 400 V · AC3 16 A / 400 V · AC15 10 A / 400 V · DC 16 A / 24 V
• Connection: 7/16-20 UNF flare (with flare nut) — two
• Max. Working Pressure: HP side 3.5 MPa (35 bar) · LP side 1.65 MPa (16.5 bar)
• Medium Temperature: −40 … +120 °C | Ambient Temperature: −30 … +65 °C | Humidity: 0-95% RH
• Protection Class: IP30 (IP44 optional)
• Dimensions: housing 123 × 63 mm · port spacing 33 ± 1 / 50 ± 1 mm · 4 × M4 mounting holes — official dimension drawing in the 2nd image
• Compatible Refrigerants: R22, R134a, R404A/R507, R407A/F, R407C, R410A, R448A/R449A, R450A, R452A, R513A
• Certifications: CE (LVD 2014/35/EU · EN 60730-1, EN 60730-2-6) · UL 508 (E480941)

• 🔧 Reading the code: PSV = pressure control · 15 = dual (LP −0.5~7 / HP 6~32 bar) · A = LP automatic reset · M = HP manual reset · L = flare connection. The brazed-connection version ends with H, the capillary-tube version with M.
• ⚠️ This variant (S51) is not certified to PED 2014/68/EU (EN 12263). For projects requiring a certified safety switch under the Pressure Equipment Directive, the -S01 variant should be selected (HP differential 5 bar instead of 4).
• There is no approval in the standard list for A2L/A3 refrigerants such as R32, R290, R717 and R1234yf; for these refrigerants, manufacturer confirmation of a specific model is required.
• When setting, keep the HP cut-out value below the system design pressure and the safety relief valve setting; select the LP cut-out value according to the evaporator design temperature.
• Do not overtighten the flare connection; applying a drop of refrigeration oil to the flare face improves sealing.