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control system unresponsive
displayed message/condition/indicates
UIM (lCD) Is Blank
The LCd on the uIM is not showing any data. The water
heater may be running and maintaining hot water or it
may not be operational. Causes for this include:
• on/off switch is turned off.
• Water heater is not plugged in.
• Tripped breaker - blown fuses.
• 120 VAC power supply problems.
• 24 VAC power supply problems.
• defective transformer.
• Wiring or plug/socket connection problems.
• uIM communication cable defective.
Important Service Reminder:
When performing any troubleshooting steps outlined in
this manual always consider the wiring and connectors
between components. Perform a close visual inspection
of all wiring and connectors to a given component before
replacement.
UIM Is Inoperable
Information is displayed on the uIM's LCd screen but the
user input buttons do not respond when pressed. unable
to navigate Control System.
Water heater may be maintaining water temperature at
the last saved setting or may not be operating at all.
Servicing should only be performed by a Qualified Service Agent
possible causes - checK/repair
• Ensure the water heater's on/off switch is in the "on"
position and is working properly - replace switch if
defective.
• Ensure the circuit breaker supplying power to the
water heater is turned on.
• Check for any blown fuses in the power supply to the
water heater.
• Ensure the water heater is plugged in to a 120 VAC
wall outlet on models equipped with a standard
appliance cord.
• on installations using a 120 VAC wall outlet for
power, ensure there is 120 VAC at the wall outlet, see
Electrical Requirements on page 6.
• Ensure 120 VAC power is properly connected in the
junction box on the back of the water heater, see
Electrical Requirements on page 6.
• Check communication cable connections at uIM's
J2 Socket (page uIM (user Interface Module) on
page 37) and the CCB's J16 Socket (page 41). Secure
power and install a new comm cable (standard Cat 5
network cable).
• Closely inspect communication ports on CCB and
uIM for damage or wear.
• Ensure 120 VAC is supplied to CCB's J3 Socket pins
1 & 3. Hot wire to pin 1, neutral wire to pin 3 (page 41).
• Check 120 VAC to transformer primary winding at
CCB's J1 socket pins 1 & 3 (page 41) with J1 plug
removed, power on.
• Check J1 plug and J1 socket on the CCB for wear
or damage. Ensure plugs and sockets are mating
properly and providing good contact.
• Check for 24 VAC from transformer secondary
winding at CCB's J1 socket pins 4 & 5 with J1 plug
inserted, power on. If 24 VAC is not present and the
two checks above were performed and the results
were successful - replace the transformer. Check
all wiring for shorts before powering up the new
transformer.
• Call the toll free support phone number on the back
cover of this manual for further assistance if the
problem has not been corrected after performing the
procedures outlined here.
• Ensure Ribbon Cable from the Button Pad overlay
is inserted correctly into the uIM J3 Socket, see uIM
(user Interface Module) on page 37. If this Ribbon
cable is not connected properly it will render some/all
of the user input buttons on the uIM inoperable.
• Call the toll free support phone number on the back
cover of this manual for further assistance if the
problem has not been corrected after performing the
procedures outlined here.
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