Replacement Part Finder

How to use it

• Read the ratings off the old part or the unit's data plate before you leave for the supply house. Take a photo of the label and the wiring.
• Confirm the part is actually bad first: see testing a run capacitor, testing a contactor, testing a blower motor, testing a transformer and testing an igniter.
• Find out why it failed. A dirty condenser, low airflow or short cycling will kill the new part too.

How the tests are judged

• Capacitors: the measured µF must fall inside the tolerance printed on the label (±5%, ±6% or ±10%).
• Contactors: volts across a closed, loaded contact should be close to zero. Guidance varies; this tool flags anything over 0.5 V as worn and over 2 V as bad. Low coil voltage points upstream, not at the contactor.
• Motors: running amps more than 10% over the nameplate FLA get flagged. Check the capacitor, bearings and blade or wheel before condemning the motor.
• Transformers: R to C should read about 24 V under load. Low voltage usually means overload, the wrong primary tap or low line voltage.

Rules of thumb

• Capacitors: same µF, same or higher voltage. Two singles can replace a dual (see the capacitor wiring diagram). See picking a replacement capacitor or contactor.
• Motors: same HP, RPM, voltage and rotation; use the capacitor the new motor's label calls for. Condenser fan matches must have the same pole count (825, 1075 and 1625 RPM motors never swap), single speed, and a shaft at least as long as the old one. PSC blower matches also need at least as many speeds as the old motor. ECM blowers aren't matched: they need the OEM-programmed part.
• Contactors: same coil voltage and poles, amp rating at or above the load.
• Transformers: same primary, 24 V secondary, same or higher VA.
• Safeties: limits and rollouts must match temperature and reset type exactly. Never go higher.

When the equipment manufacturer specifies an OEM part, especially on variable-speed blowers, inverter equipment and silicon nitride igniters, use it.