HVAC Motor Not Starting or Running Slowly? Rotom Motor Run Capacitor 36-12-370440 — Restore 12.5MFD Motor Run Capacitance

A defective motor-run capacitor is one possible cause of fan motor or blower motor starting and running problems in HVAC systems. The single-value run capacitor maintains the phase shift needed to keep the motor running efficiently. When it fails, the motor may hum, struggle to reach operating speed, run hot, or shut off on thermal overload.

⚡ Common service component in residential and light-commercial HVAC fan motors, blower motors, and condenser fan applications.

Part 36-12-370440 (also known as Rotom alternate number 12.5DV) is the Rotom specification-based replacement rated at 12.5MFD 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 MFD, Voltage, Shape and Dimensions before ordering. This is the correct specification match if ALL of the following are true:

• ✔ Your original capacitor is rated exactly 12.5MFD — capacitance must match exactly
• ✔ Your original capacitor is rated 370V or 440V — a 440V replacement may replace a 370V original; the reverse is not permitted
• ✔ Your application uses a single-value oval run capacitor (not a dual-run capacitor)
• ✔ Your mounting space accommodates an oval body approximately 2.03in wide, 1.24in deep and 3.15in high

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

🔧 Common Symptoms of a Failed Motor-Run Capacitor

• Fan or blower motor hums but fails to start
• Motor starts slowly or struggles to reach full operating speed
• Motor runs hot or trips on thermal overload
• 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 may also result from wiring, a contactor, motor winding failure, or electrical-supply problems — confirm the capacitor is the root cause before ordering.

📦 Part Details

• Part Number: 36-12-370440
• Alternate Rotom Number: 12.5DV
• Brand: Rotom / AllTemp — New
• Type: Oval Single-Value HVAC Motor-Run Capacitor
• Capacitance: 12.5MFD / 12.5 uF
• Voltage Rating: 370/440 VAC (dual-voltage)
• Shape: Oval
• Width: 2.03 in
• Depth: 1.24 in
• Height: 3.15 in
• Terminals: Quick-connect blade terminals
• Features: Built-in interrupter, UL and cUL Recognized
• Availability: In Stock
• Compatibility: Specification-based — match capacitance, voltage, shape, and dimensions to original

🔄 Also Replaces These Part Numbers

Direct oval replacements (12.5MFD, 370/440V, oval):
12.5DV (Rotom alternate), TOCF12.5 (Titan Pro), POCF12.5 (Packard), POCF12.5A (Titan HD), CR12.5X440 (Supco), 12033 (MARS Blue Box), 14033 (MARS USA), P291-1254 (Totaline / Carrier), 97F5388 (Genteq/CAPCOM), 97F5388BX (Genteq/CAPCOM), C412L (Genteq/CAPCOM), 325P12DH44A26A4Z (JARD/NGM) — electrical ratings and oval shape match; case height varies by manufacturer. Confirm mounting strap, cabinet clearance and terminal clearance before ordering.

Electrical equivalents — round shape (confirm mounting fit before ordering):
36-12R3744 (Rotom round), 12.5DVR (Rotom alternate round), TRCF12.5 (Titan Pro), PRCF12.5 (Packard), PRCF12.5A (Titan HD), CR12.5X440R (Supco), 325P12DH44M20A4Z (JARD/NGM), 43-25136-26 (Rheem/Protech), 43-TL12004-R (TrueLine), 97F5001 (Genteq/CAPCOM), C412R (Genteq/CAPCOM) — electrically equivalent; round case is not a mechanical drop-in for an oval bracket. The Rotom round equivalent (36-12R3744) measures approximately 1.65in dia x 2.78in H. A different mounting strap may be required.

⚙️ Installation

Skill Level: Advanced — Qualified HVAC Technician Required. Disconnect and lock out all power 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 that requires an oval single-value run capacitor rated at exactly 12.5MFD and 370V or 440V, provided the oval body (2.03in wide x 1.24in deep x 3.15in high) 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