A/C Parts & Filters

Matching the right A/C part

Capacitor failure tops the list of RV A/C faults, so start there when a unit hums but will not spin up or the fan drags. After that, it comes down to matching each part exactly, since ratings and mounts change from brand to brand and even model to model.

• Run and start capacitors. These store and release the jolt that gets the fan and compressor moving. Match both capacitance and voltage exactly; a run capacitor rated 14.16 MFD at 370V is not interchangeable with a 40 MFD unit even when both read 370V. Read the printing on the old one before ordering.
• Fan motors. A motor that is seized, noisy, or slow kills airflow and cooling. Confirm shaft size, rotation, and mounting to match your Coleman-Mach or Dometic unit.
• Filters and return air grills. A clogged filter is the leading cause of weak airflow and iced coils. A B&B Molders return air grill with removable filter access turns cleaning or swapping the filter into a two-minute job.
• Condensate pumps and junction boxes. Ducted and low-profile units use a small pump to move condensation, and a failed one shows up as ceiling drips. Junction boxes handle the wiring connection to the unit.
• Controllers and thermostats. A programmable controller like the Furrion Chill runs the fan speeds and setpoint. If the unit runs but ignores commands, suspect the control.

Capacitors and motors are electrical, so cut power at the panel before opening anything, and if the unit keeps tripping its protection, check your fuses and breakers for a deeper fault. Look over the covers and shrouds overhead while you are up there, and if the compressor itself is gone, a full RV A/C unit is the next step.