Low line voltage: the supply voltage to the outdoor unit is below the specified range.
Goodman L8 is low line voltage: supply to the outdoor unit is below the specified range. Like H8, the entry does not state a voltage number. Causes are low supply voltage, a tripped breaker or a blown fuse, and a unit that is not wired the way the rating plate specifies. The homeowner check is the breaker handle at the outdoor disconnect and at the main panel. The manual says to check breakers and fuses and to confirm the unit is connected as the rating plate shows. Correcting the low voltage, contacting the utility, and replacing the board when voltage is already within specification are technician steps. L8 is the voltage code in this set with that breaker check. H8 does not have it, and Carrier 46's meter step is a different manual.
Likely causes
- Low supply voltage
- Tripped breaker or blown fuse
- Unit not wired as specified on the rating plate
Safe checks for L8
- Check that the circuit breaker has not tripped (outdoor disconnect and main panel); the manual says to check circuit breakers and fuses and verify the unit is connected as specified on the rating plate
- Techniciancorrect the low line voltage condition and contact the local utility if needed; if voltage is within specification, replace the board
Capacitors can hold a charge after the power is off. Safety terms.
When to call a pro
Call a licensed HVAC technician; contact your utility if the supply voltage is low.
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Multimeter for appliance and HVAC diagnosis: guide
In this code: Low supply voltage
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