Generac Generator Error Code 1850: How to Fix It

Q: Can I use water instead of coolant?

No. Water alone does not provide proper freeze protection or corrosion inhibition. Always use a 50/50 mix of antifreeze and distilled water or a pre-diluted coolant that meets Generac specifications.

Q: How do I reset error code 1850 after adding coolant?

After adding coolant, the error should clear automatically when the coolant level is restored. If it doesn't, turn the generator off, wait 30 seconds, then restart. If the code persists, there may be a sensor fault or leak.

Q: What type of coolant does a Generac generator use?

Generac recommends using a 50/50 mix of ethylene glycol antifreeze and distilled water, or a pre-mixed coolant that meets ASTM D3306 standards. Do not use universal 'all vehicles' coolant unless it is approved for small engines.

Q: Can low coolant cause my Generac generator to shut down?

Yes. The low coolant sensor triggers error code 1850 to protect the engine from overheating. The generator will typically shut down or prevent starting until the coolant is topped off.

Q: How often should I check the coolant level?

Check the coolant level at every oil change (every 100-200 hours of operation or annually). Also inspect for leaks before and after extended use.

Abstract

Error code 1850 on your Generac generator indicates low coolant level. This error typically appears on the controller display and prevents the generator from starting or running. The fix involves safely topping off the coolant reservoir and checking for leaks.