Danfoss 8173231 Run Capacitor – 40 µF / 440 V, For CSR and PSC Compressors

Danfoss 8173231 is a 40 µF / 440 V run capacitor used in compressor motors. It is used in Danfoss CSR start kits, HHP015, MLZ/MLM015-5 and PSC compressor systems.

Run Capacitor: Stays in the Circuit as Long as the Motor Runs

Do not confuse it with a start capacitor. A start capacitor provides high torque to the motor only at the moment of starting and is switched out of the circuit by a relay within a few seconds. A run capacitor, on the other hand, stays in the circuit as long as the motor runs: it continuously feeds the auxiliary winding, corrects the power factor, and increases efficiency and torque.

Therefore, the two cannot be used interchangeably. A start capacitor left permanently in the circuit will soon burst, while a run capacitor cannot provide starting torque.

Technical Specifications (Official Manufacturer Data)

• Code: Danfoss 8173231
• Capacitance: 40 µF
• Voltage: 440 V
• Type: Run capacitor — continuously in circuit
• Compatible Systems: CSR start kits · HHP015 · MLZ/MLM015-5 · PSC compressors
• Net Weight: 0.26 kg | EAN: 5702428802444
• Certificates: CE · UKCA · UL

• ⚠️ Always discharge before replacing. The capacitor retains a charge even after the power is cut; do not touch its terminals before discharging it through a suitable resistor.
• Match the capacitance and voltage values exactly. A lower µF reduces torque, a higher µF strains the winding. The voltage rating must be at least 440 V.
• 🔧 Fault symptom: With a weakened run capacitor, the compressor starts with difficulty, overheats and trips the thermal protector. Measure it with a capacitance meter and compare it with the label value.
• ℹ️ Package note: Danfoss lists it in its catalog as a pack of 10; supply confirmation is recommended for single-unit sales.