b7 Gas line (valve) temperature sensor open or shorted

What the control is telling you

The control reads an out-of-range value from the gas line (valve) temperature thermistor (open circuit or short).

Applies to: Gree Multi21+ 18-24k multi-zone (MULTI..HP230V1CO)

Likely causes

• Gas line (valve) temperature sensor unplugged, loose or with poor pin contact
• Sensor element damaged
• Wire chafed or shorted, or board parts touching
• outdoor board sensing circuit faulty

Test and repair steps

1. Kill power, then reseat the sensor plug on the board and look for corroded or loose pins.
2. Unplug the sensor and measure its resistance; compare it with the sensor temperature/resistance chart in the service manual for the actual pipe or air temperature.
3. Check the sensor lead for chafing or crushed wire and look for parts on the board bent over and touching (short).
4. Replace the sensor with the same part if it reads open, shorted or far off the chart.
5. If the sensor and plug are good and the code stays, replace the board that reads it.

Models that show this code

2 models in Gree Multi21+

Other codes on the same units

• b5 Liquid line (valve) temperature sensor open or shorted
• C5 Jumper (capacity) cap missing or bad
• E1 High pressure protection
• E3 Low pressure protection
• E4 Compressor discharge temperature too high
• E5 Overcurrent protection (whole unit)
• E6 Indoor/outdoor communication fault
• E7 Mode conflict between indoor units (status)