L1 Lockout - low pressure switch tripped 3 times

What the control is telling you

The low pressure switch opened 3 times during the same thermostat call, so the outdoor control locked out the compressor and fan.

Applies to: Communicating 2-stage condensers and heat pumps with the PCBHR104 or PCBHR105 outdoor control (7-segment display): ASXC16/18, GSXC16/18, DSXC16/18, ASZC16/18, GSZC16/18, DSZC16/18

Likely causes

• Low refrigerant charge
• Restricted liquid line (drier, kinked line)
• Indoor blower motor failed or not running
• Thermostat set very low
• Faulty low pressure switch

Test and repair steps

1. Warning: Kill power to the outdoor unit before touching wiring, the compressor terminals or the control.
2. Check charge with superheat/subcooling and correct it; leak check if low.
3. Look for a temperature drop across the liquid line drier or any kinks - repair restrictions.
4. Confirm the indoor blower runs at the right speed and filters/coil are clean.
5. Check the thermostat set point.
6. Test the low pressure switch (opens about 21 psig, closes about 50 psig).
7. To reset a lockout, interrupt the 24 VAC supply to the outdoor control (power cycle the low voltage), then retest.

Models that show this code

24 models in Goodman/Amana ComfortNet ASZC/GSZC/DSZC

Other codes on the same units

• d3 Configuration mismatch - shared data does not match hardware
• d4 Shared data from the loader rejected
• E5 Outdoor control low-voltage fuse open
• H8 High line voltage
• L2 Lockout - high pressure switch tripped 3 times
• L6 Lockout - open start circuit detected 4 times
• L7 Lockout - open run circuit detected 4 times
• L8 Low line voltage