Demand Duo
™
R
-
Series Installation and Operation Manual
44
To Display Diagnostic Information
To display the most recent diagnostic information codes press and hold the
“
On/Off
”
button for two
seconds on the controller. While holding the
“
On/Off
”
button press the (Up) button. The last nine
diagnostic codes will flash one after the other. To exit this mode press the
“
On/Off
”
and (Up) button
as before.
To enter or exit the maintenance monitor information mode, press and hold the (Down) button for
two seconds and without releasing it, press the
“
On/Off
”
button.
To obtain the tankless water flow rate, press the (Up) or (Down) buttons until
“01”
displays. The
water flow rate will then appear. For example
“58”
means 5.8 gal/min.
To obtain the tankless outgoing water temperature, press the (Up) or (Down) buttons until
“02”
displays. The temperature will appear in degrees Fahrenheit.
This water heater is designed to display diagnostic codes. If there is a potential operation concern, refer
to the code and remedy in this section.
Data
Unit
No.
Water flow rate
0.1 gal/min
01
Outgoing water temperature
Degrees Fahrenheit
02
08
Incoming Tankless Temperature
Degrees Fahrenheit
Some of the checks below should be performed by a licensed professional.
Owners should never attempt any action that they are not qualified to perform.
WARNING
1 0
Air Supply or Exhaust Blockage
•
Confirm exhaust vent / flue is not
blocked.
•
Confirm Intake Filter Exhaust Connector
(IFEC) is not blocked or dirty.
•
Check all vent components for proper
connections.
•
Ensure approved venting materials are
being used.
•
Check fan for blockage.
1 1
No Ignition (Heater Not Turning On)
•
Check that the gas is turned on at the
water heater, meter, or cylinder.
•
If the system is propane, make sure that
gas is in the tank.
•
Ensure appliance is properly grounded.
•
Ensure gas type and pressure are
correct.
•
Ensure gas line, meter, and/or regulator
is sized properly.
•
Bleed all air from gas lines.
•
Verify dip switches are set properly.
•
Ensure igniter is operational.
•
Check igniter wiring harness for damage.
•
Check gas solenoid valves for open or
short circuits.
•
Remove burner cover and ensure all
burners are properly seated.
•
Remove burner plate and inspect burner
surface for condensation or debris.
•
Check the ground wire for the PC board.
