Gree / Mace b1

Gree / Mace error code B1 indicates: Gree-Mace G10 Inverter / Free Match / GMV5 / GMV6 Multi-VRF Commercial & Residential HVAC: Diagnostic fault code b1 registered by the microcomputer controller. Outdoor unit subcooler liquid pipe temperature thermistor sensor fault.

The primary root cause for Gree / Mace code B1 is: On Gree-Mace appliances engineered with Gree G10 Inverter low-frequency torque control, intelligent dual-stage rotary compressor, 46 Ω electronic expansion valve stepping motor coils, high-voltage PFC boost circuit (380V DC), and precision NTC thermistors (15 kΩ ambient, 20 kΩ coil, 50 kΩ discharge): subcooler liquid pipe temperature thermistor open or short-circuit Metrological tolerance verification: NTC thermistor 20 kΩ at 25°C, 32.5 kΩ at 10°C..

To resolve error code B1: Disconnect mains power before servicing. Unplug the harness at the main PCB and use a calibrated digital multimeter: measure subcooler probe resistance across harness plug at outdoor PCB. Inspect contacts for pin oxidation or loose terminals. Replace defective part if out of tolerance, re-energize and clear error: Using the remote controller: point at the unit and press 'LIGHT' 6 times in 3 seconds (or hold 'TURBO' + 'MODE' for 5 seconds) to enter diagnostic query mode. For inverter lockout errors (H5, HC, P0, P8, E6), switch off the external electrical isolator / circuit breaker for at least 3 minutes to allow DC bus capacitors to fully discharge.

Resetting power (unplugging for 5–10 minutes) clears temporary memory errors. However, if Gree / Mace code B1 persists, the physical component causing On Gree-Mace appliances engineered with Gree G10 Inverter low-frequency torque control, intelligent dual-stage rotary compressor, 46 Ω electronic expansion valve stepping motor coils, high-voltage PFC boost circuit (380V DC), and precision NTC thermistors (15 kΩ ambient, 20 kΩ coil, 50 kΩ discharge): subcooler liquid pipe temperature thermistor open or short-circuit Metrological tolerance verification: NTC thermistor 20 kΩ at 25°C, 32.5 kΩ at 10°C. must be inspected or replaced.

Set a digital multimeter to ohms (Ω). Disconnect power and test NTC Temperature Sensor Probe (Thermistor) across Across sensor pins 1-2 (unplugged harness). Expected nominal reading is 4.8kΩ–12kΩ (at 20°C–25°C). Tolerance: Negative temperature coefficient: resistance drops smoothly when warmed with fingers. OL = open circuit..

Standard electrical safety protocol: 1. Disconnect 230V mains power before opening panels. 2. Verify zero voltage at test points. 3. Allow hot water or heating elements to cool below 30°C before handling.