HVAC Motor Not Running Properly? Rotom Motor Run Capacitor 36-40-370440 — Restore 40MFD Motor Run Capacitance

A defective motor-run capacitor is one possible cause of HVAC fan or compressor motor starting and running problems. The run capacitor maintains the phase shift required to keep the motor spinning efficiently under load. When it fails, the motor may hum, struggle to reach operating speed, run intermittently, or overheat.

⚡ Common service component in residential and light-commercial HVAC condensing and air-handling units.

Part 36-40-370440 is the Rotom specification-based replacement rated at 40MFD and 370/440 VAC that may restore proper motor-run support when testing confirms the original capacitor is defective and no related motor or electrical fault remains.

❓ Is This the Right Part?

Confirm the original capacitor’s capacitance, voltage, and physical dimensions before ordering. This is the correct specification match if ALL of the following are true:

• ✔ Your original capacitor is rated exactly 40MFD — capacitance must match exactly
• ✔ Your original capacitor is rated 370V or 440V — a 440V replacement may replace a 370V original when capacitance matches; the reverse is not permitted
• ✔ Configuration is a single-value run capacitor (not a dual-run)
• ✔ Your mounting space accommodates an oval body approximately 2.80" wide × 1.77" deep × 3.55" high

Not sure? Send us your capacitor label specs — we’ll confirm before you order.

🔧 Common Symptoms of a Failed Motor-Run Capacitor

• Fan or compressor motor hums but fails to start or reach operating speed
• Motor starts then shuts off on thermal overload shortly after
• Motor runs hot or draws higher-than-normal amperage
• Capacitor body visibly bulged, leaking, or reads out-of-tolerance on a capacitance meter

✔ If these symptoms match and capacitor testing confirms a defective reading, this is a likely failed component. Similar symptoms can also result from wiring, a contactor, motor, or electrical-supply fault — confirm the capacitor is the root cause before ordering.

📦 Part Details

• Part Number: 36-40-370440
• Alternate Rotom Number: 40DV
• Brand: Rotom / AllTemp — New
• Type: Single-Value Oval HVAC Motor-Run Capacitor
• Capacitance: 40MFD / 40 µF
• Voltage Rating: 370/440 VAC (dual-voltage)
• Shape: Oval
• Dimensions: 2.80" W × 1.77" D × 3.55" H
• Features: Built-in pressure interrupter, UL and cUL Recognized
• Compatibility: Specification-based — match capacitance, voltage, shape, and dimensions to original

🔄 Also Replaces These Part Numbers

Direct oval replacements (40MFD, 370/440V, oval):
40DV (Rotom alternate), TOCF40 (Titan Pro / Packard), POCF40 (Packard), POCF40A (Titan HD), PPS40440OV (ProParts), 45400H (DiversiTech), TP40440 (TradePro), CR40X440 (Supco), LCR40X440 (Supco Linebacker), 12045 (MARS Blue Box), 12945 (JARD / MARS), 14045 (MARS USA), P291-4004 (Totaline)

Electrical equivalents — round shape (confirm mounting fit before ordering):
36-40R3744 (Rotom round), TRCF40 (Titan Pro), PRCF40 (Packard), PPS40440RD (ProParts), 45400R (DiversiTech), TP40440R (TradePro), CR40X440R (Supco), LCR40X440R (Supco Linebacker), 14245 (MARS USA), P291-4004R (Totaline) — same 40MFD and 440V electrical rating; round case requires confirmation that mounting strap and cabinet space can accommodate the different shape.

⚙️ Installation

Skill Level: Advanced — Qualified HVAC Technician Required. Disconnect and lock out all power to the unit before opening the electrical compartment. HVAC capacitor diagnosis and replacement should be completed by a qualified technician. Photograph the original wiring before disconnecting. Connect the replacement to the same terminals and confirm all connections are secure before restoring power and testing motor operation.

✓ Specification Compatibility

This capacitor is compatible with any HVAC motor application requiring a single-value oval motor-run capacitor rated at exactly 40MFD and 370V or 440V, provided the oval body (2.80" W × 1.77" D × 3.55" H) fits the existing mounting bracket. Compatibility is determined by electrical specification and physical fit — not by equipment model number. Contact us with your original capacitor label before ordering if you are unsure.

💡 Pro Tip