HVAC Code Lookup

LG Mini-Split Code CH53

Soft lockoutShown as: Outdoor LED01 (red) blinks 5 times, LED02 (green) blinks 3 times

Communication failure from the outdoor unit to the indoor unit(s). Same fault family as CH05, but reported from the outdoor side - the outdoor board is not hearing the indoor unit.

Manual wording: “Communication failure between outdoor unit and indoor unit(s)”

Documented for: All LG residential mini-splits, single-zone and multi-zone

Likely causes, most common first

  1. No power on the indoor unit
  2. Indoor/outdoor unit power connection error, or the communication line not installed
  3. Improper connection at the terminal block for the communication wire
  4. Improper wiring of the communication L-N wire between indoor and outdoor units
  5. Communication error caused by external electrical noise
  6. Indoor/outdoor communication circuit parts burned, or no power due to a burned indoor or outdoor PCB

What you can safely check yourself

  • Check the breakers for BOTH the indoor and outdoor unit are on and not tripped
  • Check the outdoor disconnect switch next to the condenser is switched on
  • Turn the system off at the breaker for three minutes, then back on

When to call a technician

If power is on at both units and CH53 stays, the interconnecting wiring or a control board is at fault. That is technician work.

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