HVAC Motor Not Running Properly? Run Capacitor 36-45R3744 — Fix Motor Starting Failure Fast

If your HVAC motor hums but won’t start, runs weakly, or draws excessive current, a failed run capacitor is one of the most common causes. In PSC (permanent split capacitor) motors, the run capacitor provides continuous phase-shift support while the motor is operating. When it fails, the motor loses efficiency, struggles to start, or stops running entirely. ⚡ Common failure point in condenser fan motors, blower motors, and compressor circuits. Part 36-45R3744 is the Rotom OEM replacement that restores proper run capacitance to compatible 45MFD PSC motor circuits.

🇺🇸 Matching U.S. Part Number: 36-45R3744

❓ Is This the Right Part?

This is the correct fix if ALL of the following are true:

• ✔ Motor circuit is confirmed to require a single 45MFD run capacitor (not a dual-run capacitor)
• ✔ Electrical supply to the unit is confirmed OK
• ✔ Motor windings are not open or shorted
• ✔ ONLY problem is the motor failing to start or running below rated speed

Not sure? Send us your model number — we’ll confirm before you order.

🔧 Common Symptoms

• Motor hums but won’t start or start is sluggish
• Fan or blower runs at reduced speed
• Motor overheats or trips thermal overload
• Unit draws higher than normal current
• Capacitor is visibly bulged, leaking, or measures out of spec

✔ If these symptoms match, this is the most likely failed component in the motor circuit.

✔ In most cases, replacing the run capacitor restores normal motor operation immediately.

📦 Part Details

• Part Number: 36-45R3744
• Type: Single motor-run capacitor (not a dual-run, not a start capacitor)
• Capacitance: 45 µF
• Voltage: 370/440 VAC
• Shape: Round
• Diameter: 2.00 in
• Height: 4.33 in
• Features: Built-in pressure interrupter; UL and cUL recognized
• Brand/OEM: Rotom / AllTemp
• Direct Round Equivalents: PRCF45, PRCF45A, TRCF45, PPS45440RD, 45450R, TP45440R, CR45X440R, 12248, 12748, 14248, USA2216, C445R, 97F9645, 97F9645BX

⚙️ Installation

Skill Level: Moderate — 20 to 45 minutes. Disconnect and lock out power to the unit before opening the electrical compartment. Capacitors retain a hazardous charge after power is removed — discharge safely before handling. Match the terminal connections exactly to the original wiring. Confirm mounting strap diameter and cabinet clearance before installing — dimensions vary between equivalent brands. Diagnosis and replacement should be completed by a qualified HVAC technician.

✓ Compatible Models

Compatibility for this capacitor is specification-based. Capacitance must remain exactly 45MFD, and the replacement voltage must equal or exceed the original equipment requirement. Confirm the round shape and dimensions (2.00” × 4.33”) fit the mounting strap and cabinet clearance before ordering. Contact us to verify your model number before ordering.

💡 Pro Tip