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Step by Step Guide: Cleaning Coleman MACH RV A/C Coils

Step‑by‑Step Guide: Cleaning Coleman MACH RV A/C Coils

This covers both coils:

  • Condenser coil (rear, outside air path)
  • Evaporator coil (front, inside air path)

01

Disconnect Power

Safety First

Prevents accidental fan or compressor startup while you're working.

  • Turn off shore power
  • Switch off generator
  • Disconnect 12V fuse for the A/C control board if accessible

02

Remove the Shroud

Gives access to both coils and the fan section.

  • Remove the perimeter screws around the plastic shroud
  • Lift the shroud straight up and set aside
  • Inspect for wasp nests, debris, or loose insulation

03

Access the Condenser Coil (Rear Coil)

This is the coil exposed to outside air and usually the dirtiest.

  • Locate the rear-facing coil behind the condenser fan
  • Remove any top cover or sheet-metal guard if present
  • Check for matted debris, cottonwood, or pet hair

04

Dry Clean the Condenser Coil

Removes bulk debris before applying cleaner.

  • Use a soft brush or fin comb to remove surface debris
  • Blow out coil from inside → out using compressed air (low pressure)
  • Avoid bending fins; straighten any that are crushed

05

Wet Clean the Condenser Coil

Most Effective

Restores airflow and heat rejection efficiency.

  • Use a non‑acid foaming coil cleaner (4171-45 NuCalgon) rated for aluminum
  • Spray from inside → out to push dirt outward
  • Let foam dwell 5–10 minutes
  • Rinse gently with low‑pressure water (never pressure‑wash)

06

Access the Evaporator Coil (Front Coil)

This coil sits in the front section and feeds the ductwork.

  • Remove the front sheet‑metal cover over the evaporator section
  • Watch for screws hidden under foil tape
  • Inspect the foam divider; repair gaps to prevent air bypass

07

Clean the Evaporator Coil

Dust and biofilm here cause freeze‑ups and poor cooling.

  • Use evaporator-safe cleaner (non‑rinse or rinse type)
  • Spray coil from return-air side → forward
  • If using rinse type, flush lightly with water
  • Avoid soaking electrical components or the control box

08

Clean the Drain Pan & Check Drainage

Prevents water leaks inside the RV.

  • Wipe out the drain pan under the evaporator
  • Ensure drain holes are clear
  • Remove algae or sludge buildup

09

Inspect Fan Motor & Blades

Dirty blades reduce airflow and increase amp draw.

  • Clean condenser and evaporator fan blades
  • Spin the motor shaft to check for rough bearings
  • Verify motor mount and shaft seal are intact

10

Reassemble & Test

Ensures proper airflow and operation after cleaning.

  • Reinstall all sheet-metal covers and the shroud
  • Restore power
  • Run A/C for 10–15 minutes
  • Check for strong airflow and normal compressor cycling

4171-75 Coil Cleaner Nu-Calgon Spray Can Foaming (No Rinse)