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S-1B Controller

The S-1B is a generator-set controller. It is used on generator sets from Northern Lights, including the M673, NL673, NL753 and NL773LW4.

Generator sets

Northern Lights

Brand

4.5–36 kW

Power range

Fuel types

Generator sets using this controller

Northern Lights M673 Northern Lights NL673 Northern Lights NL753 Northern Lights NL773LW4 Northern Lights NL843N Northern Lights NL944D3 Northern Lights NL944T3

Engines paired with this controller

Northern Lights 753K Northern Lights 753c Northern Lights L643 / L673 Northern Lights L673L Engine Northern Lights L773L Northern Lights L843 Northern Lights L944 Northern Lights M753

Troubleshooting

Symptoms & remedies

Symptom	Cause	Remedy
Battery Will Not Charge	Loose or corroded connections	Clean and tighten battery connections
Below Normal Engine Temperature	Thermostats not working properly	Check thermostats.
Engine Emits Black or Gray Exhaust Smoke	Clogged or dirty air cleaner	Service air cleaner.
Engine Emits Black or Gray Exhaust smoke	Clogged or dirty air cleaner	Service air cleaner.
Engine Emits White Exhaust smoke	Improper fuel	Use correct fuel for temperature.
Engine Emits White Smoke	Improper fuel	Use correct fuel for temperature.
Engine Hard to Start or Will Not Start	Improper starting procedure	See starting section of this manual. Take special note of Bypass Switch operation
Engine Knocks	Insufficient oil	Call your dealer.
Engine Overheats	Low coolant level	Fill tank or radiator to proper level; Check hoses for loose connections and leaks.
Engine Runs Irregularly or Stalls Frequently	Below normal engine temperature	Remove and check thermostat
Entire Electrical System Does Not Function	DC circuit breaker tripped	If breaker is tripped, reset it
High Fuel Consumption	Improper type of fuel	Use correct fuel for temperature.
High Oil Consumption	Break-in period	Oil consumption decreases after break in.
Lack of Engine Power	Intake air restriction	Service air cleaner
Low Oil Pressure	Low oil level	Fill crankcase to proper level.
Starter Cranks Slowly	Low battery output	Battery is too small; Battery cables are too small
Starter Inoperative	DC circuit breaker tripped	If the breaker is tripped, reset it

Fault codes and symptom→remedy steps extracted from this controller’s service/owner documentation; verify against the official manual before servicing. Aggregated from the service documentation of generator sets built on this controller.