You may have to replace the sensor but first you can try a reset by turning the unit off at the switch on the gas valve wait a minute then turn the switch back on.
Honeywell water heater gas control valve reset.
Had to fix a water heater that had the honeywell 5 blinks of death error code.
Keep track of which front is which.
Turn the water heater s gas valve switch to the off position wait for a few seconds and then flip the switch to the on position to reset the system.
The water heater s gas valve is located near the bottom of the unit and connects to your home s natural gas line.
Slide the ribbon of wires out of the clip on the housing and the front of the gas valve is free.
Repeat these steps with the new gas valve.
8 reset gas valve this will only appear after the gas valve has been shutoff and continues to produce a current to the thermopile.
Reverse the above steps to mount the new front onto the old back that s still hooked to the water heater.
Turn the gas control dial to off and let sit for one minute.
If your water heater does not begin working or another lock out condition occurs have a competent hot water heating specialist diagnose the system and make repairs.
Assuming you don t have a power vented unit a 7 flash means the gas control valve has failed and needs to be replaced.
After resetting it several times and bypassing the thermal switch i noticed.