HVAC Code Lookup

LG Mini-Split Code CH04

Soft lockoutShown as: Indoor unit LED1 (units place) blinks 4 times

Drain pump / float switch error. Condensate is backing up inside the indoor unit - the float switch has tripped or the drain pump is not clearing water. LG's consumer page describes it as water formed inside the indoor unit not being drained.

Manual wording: “Drain pump malfunction.”

Documented for: LG mini-split indoor units fitted with a drain pump or float switch (cassette, ducted, and wall-mount units with an accessory pump)

Likely causes, most common first

  1. Drain pump fault
  2. Drain hose clogging
  3. Float switch fault
  4. Missing or badly seated short key (jumper) on the indoor PCB float-switch connector, on models that do not use a float switch

What you can safely check yourself

  • Follow the condensate drain line to where it exits and check for a clog, kink, or standing water
  • Check the drain line is not pinched, crushed, or running uphill
  • Clear any obvious blockage at the outdoor end of the drain line
  • Turn the system off at the breaker for one minute and back on after clearing an obvious drain blockage

When to call a technician

If the drain line is clear and CH04 returns, the drain pump or float switch inside the unit has failed and needs a technician. Do not remove or bypass the float switch - it is what stops the unit flooding your ceiling or wall.

A LG mini-split throwing this code repeatedly has a reason — clearing the code without fixing the cause just hides it.

Sources

Other LG codes