SER
VICE PR
OCEDURE
S
On-Demand Water Heater Service Handbook for 240, 340 & 540 Condensing Models • 45
Diagnostic Mode
Diagnostic mode allows you to
discover various pieces of information
about one or more water heaters,
even if they are linked together
through an Easy-Link or Multi-Unit
system.
Individual Unit
1. To enter diagnostic mode,
complete this step on the parent
heater or on the remote that
is attached to the multi-unit
controller:
Press the HOT button and the COLD
button simultaneously for at least
five seconds. See Figure 38.
2. Use the HOT or COLD buttons to scroll
through the mode numbers. Continue
until you reach the desired mode
number. ( Figure 39.)
See Table 18, page 47 for a list of
mode numbers and their meanings.
3. Press the INFO button to select the
mode number. The information
will display on the controller.
4. To exit diagnostic mode, press and
hold the HOT and COLD buttons
simultaneously for at least five
seconds.
NOTE: You may exit diagnostic mode
by pressing the ON/OFF button.
Also, if left alone, the display will exit
diagnostic mode automatically after
30 minutes.
Multiple Units in a Linked
System (540 [T-H3] Models
Only)
1. To enter diagnostic mode, press
the HOT button and the COLD
button simultaneously for at least
five seconds. See Figure 38.
"COLD"
Button
"HOT" Bu
tton
Press the "HOT" bu
tt
on or the "COLD"
bu
tt
on to set the hot water temperature.
STAND BY LED
(Orange)
The indicator is ON to show that
power is ON.
IN USE LED
(Green)
The lamp lights during combus
tion.
"INFO"
Button
Each
time
the bu
tt
on is pressed,
the opera
tion
mode is selected
in the sequence of the following.
Inlet water
temperature
Outlet water
temperature
Water
fl
ow
When the
STAND BY
LED is ON, the
hot water temperature will be
displayed.
Display
for
Temperature
"ON/OFF"
Button
Press this bu
tt
on to
start or stop opera
tion.
Temperature controller
Temperature remote controller
Figure 38.
Mode #
Informa
tion
Figure
39
.
