56
11.
If no arcing is detected, the unit is ready for operation.
Solid State Step Controller Thermistor - Replacement
The solid state step controller thermistor is connected by wire to the step controller, and
via compression fitting to the tank. It is accessible through the electric control cabinet. If
the thermistor is found to be malfunctioning and needs to be replaced, follow the
procedures detailed below.
t
Solid state component boards are very fragile and subject to damage from any type
of electrical charge - even static electricity. Before touching any board, assure that
the electric power source has been shut off and locked out all static electricity has
been removed from your body by touching a suitable ground (such as the cold
water inlet piping).
1.
Follow Steps 1 through 5 of the shutdown procedure (page 19) to take the unit
off-line before attempting to replace the pressure gauge.
t
The combination of electricity and water can pose a
very dangerous situation
.
Assure that all power has been
shut off / disconnected and locked out
in an
approved manner, before attempting any installation or maintenance procedures.
2.
After assuring that the power has been turned off and locked out, the pressure bled
from the tank, the water drained, and the unit has cooled, unlock and open the
electric control cabinet door.
3.
Open the electric control cabinet and locate the probe.
Note: Care should be taken not to damage the solid state step controller or any of its
component boards during these procedures.
4.
Locate the point at which the thermistor enters the tank. This should be just above
the highest heating element. It may be necessary to move some of the fiberglass
insulation to allow access.
5.
Trace the wires back to the step controller. Tag them for proper replacement after
the new thermistor is installed. Disconnect the wires.
6.
The body of the compression fitting that mounts the thermistor to the tank can be
difficult to remove. To facilitate removal, cut the wires with a pair of diagonals or
wire cutters close enough to the compression fitting body to allow a six (6) point
socket to be used to remove it from the tank.
Summary of Contents for EHB
Page 41: ...38 ...
Page 62: ...59 9 If no leaks are found follow the startup procedures page 17 to put the unit back on line ...
Page 64: ...61 Appendix A cont d ...
Page 65: ...62 Appendix A cont d ...
Page 68: ...65 ...