Lennox 89M83 Capacitor

What a Dual Run Capacitor Does

Your air conditioner relies on two key electric motors outdoors: the compressor and the fan motor. A dual run capacitor houses the circuits for both motors inside a single casing.

This part has three top terminals labeled HERM, FAN, and C. The HERM terminal connects to the compressor. The FAN terminal connects to the outdoor fan. The C terminal serves as the common connection.

When a dual run capacitor fails, one or both motors will struggle. You might hear the outdoor fan hum without spinning, or the compressor may fail to start entirely.

Understanding the 89M83 Specifications

The label on the Lennox 89M83 lists key ratings that define how it operates. Matching these ratings protects your equipment from electrical damage.

• Capacitance: 45/10 MFD. This means it provides 45 microfarads for the compressor circuit and 10 microfarads for the fan motor circuit.
• Voltage: 440 VAC. This is the maximum alternating current voltage the part is rated to handle safely.
• Material: Dual Run Capacitor. It contains dual internal sections designed to assist two separate motors continuously.

How to Confirm a Replacement Matches

When looking for a matching part, you must check the electrical ratings on the metal case. A replacement does not have to look identical, but its ratings must follow specific rules.

• µF (MFD): The capacitance rating must be the same. A match for this part must read 45/10 MFD.
• Volts: The voltage rating must be the same or higher. A 440 VAC rating works safely in place of a 370 V unit, but you can never use a lower voltage rating.
• Shape: Dual run capacitors come in round or oval cases. Pick the shape that fits the mounting bracket in your unit so it stays secure.

Signs of Failure and Safe Replacement Steps

A fan that hums but will not spin is often caused by a bad capacitor rather than a broken motor. When you need to swap the part, work slowly and carefully.

Always take a photo of every wire before removing the old part. Move the wires one at a time to the matching terminals on the new unit to avoid mistakes.

1. Shut off power at the main breaker panel and pull the outdoor disconnect handle.
2. Use a meter to test for power and confirm the circuit is dead.
3. Discharge the capacitor terminals using an insulated tool.
4. Take a clear photo of the existing wire connections.
5. Disconnect the wires and mount the replacement in the bracket.
6. Reconnect the wires one by one to C, HERM, and FAN to match your photo.

Read your old part

1. Look at the printed label on your existing capacitor can.
2. Check that the part number reads 89M83.
3. Confirm the capacitance rating states 45/10 MFD.
4. Verify the voltage rating shows 440 VAC.
5. Inspect the terminal posts to confirm it has three sets of terminals labeled HERM, FAN, and C.