GE GEH Series Service Manual page 34

The T2 tank sensor provides the control with a
resistance value for determining tank
temperature.
It is the only feedback the control has for tank
temperature.
Just before the compressor starts, controls
checks to ensure T2 sensor temperature is
between 30°F and 160°F
The sensor is considered open if the voltage at
the board is greater than 4.88VDC and shorted
if less than .098VDC.
A T2 sensor fault is considered a critical failure
and will completely shut the system down,
causing no hot water.
CONTROL
BOARD
34