Error code · Water Heater

GE GeoSpring GEH50DFEJ Code F18: Current transformer wiring

High · stop use, call now

Code: F18
Appliance: Water Heater
Brand: GE
Warranty: 30-day workmanship

What F18 means

F18 on 2014-2016 GE GeoSpring hybrid electric water heaters in the GEH50DEEJ, GEH50DFEJ, GEH80DEEJ and GEH80DFEJ series means the current transformer is wired incorrectly. The current transformer is the small sensor that lets the control measure how much current the heating and heat pump circuits draw. When its wiring is reversed, loose or misplaced, the control cannot read the draw correctly and reports F18. This is most often seen after a board or sensor was replaced.

Common causes of F18

Current transformer connector and wire routing
Whether the sensor was reinstalled or replaced recently
Wire damage near the control
The control's current-sensing input

✓ One safe check you can try

1. Note whether any repair was done on the unit before F18 appeared. 2. Turn the breaker off if you smell anything hot or see discoloration. 3. Do not open the wiring compartment. 4. Contact us so a technician can inspect the sensor wiring.

! Why to stop there

The wiring of a sensor is not something an owner can safely verify.
We inspect the connections with power isolated and compare them with the correct routing.
Correct routing is verified against the right wiring layout before anything is replaced.

Opening a panel yourself does not automatically cancel a manufacturer warranty, but it can cause accidental damage, and some manufacturers set their own service conditions. Check your warranty terms, or ask us, before deciding.

→Same appliance

Other Water Heater codes

System FailureGE GeoSpring GEH50DXSRGA Message "System Failure": Immediate attention Wiring to unit incorrectGE GeoSpring GEH50DNSRSA Message "Wiring to unit incorrect. Must be 240V not 120V": Supply check EPGE GeoSpring GEH50DXSRGA Code EP: Energy price signal F5, F6, F7, F8GE GeoSpring First-Generation GEH50DEED Codes F5-F8: Sensor failures F9GE GeoSpring First-Generation GEH50DEED Code F9: Bottom element problem F10GE GeoSpring First-Generation GEH50DEED Code F10: Top element problem F11GE GeoSpring First-Generation GEH50DEED Code F11: Tank must be filled bAd linE (F12)GE GeoSpring First-Generation GEH50DEED Code bAd linE (F12): Supply voltage low

F18F18 questions

What is a current transformer?

It is a sensing coil around a wire that tells the control how much current is flowing. F18 means the control's readings do not agree with how the sensor is connected.

Did something I did cause F18?

Unlikely if you only used the panel. It usually follows wiring work on the unit. If someone recently serviced it, mention that when you call.

Can I keep using the water heater?

If it still makes hot water and nothing smells hot, it may run, but we suggest turning it off at the breaker if you are unsure. The wiring is worth checking quickly.

Book a visit

Still seeing F18?

A technician diagnoses it on site and gives you the price in writing before any work starts.

(713) 547-5545