4
1.0
DISPLAY CODES
The Lochinvar TTB has two three digit LED display on the front panel; these displays are used for setting the
desired stored water temperature and for aiding diagnosis if the unit is not firing.
1.1
DOUBLE NUMBERS
If two numbers (e.g. 80) are displayed on the upper display, the water heater is operating normally and the value
displayed is the setpoint of the water heater. If two numbers (e.g. 80) are displayed on the lower display, the lower
burner has a demand present and the value displayed is the setpoint for the burner. If the green LED below either
display is illuminated, this signifies that the relevant burner is active.
1.2
DIAGNOSTIC CODES
When a code is permanently displayed (i.e. not flashing), on the upper or lower display, the relevant burner is
waiting for a specific condition before beginning the firing sequence. The following table gives a list of diagnostic
codes, descriptions of the fault and solutions.
Code Fault
Solution
A1
System pressure too low
Check system pressure
A2
Outlet temperature too high
Wait for outlet temperature to drop
A3
External sensor temperature too high
Wait for temperature to drop
A5
Anti-cycling time
Wait for time period to expire
A6
Fan speed too high
Wait for fan speed to drop
A7
Fan speed too low
Wait for fan speed to increase
A8
Water flow through heater too low
Wait for water flow to increase
C1
Flame simulation
Wait for burner to extinguish
C3
High limit thermostat activated
Wait for water temperature to drop
E6
Heater running in safe operation mode
Contact qualified service personnel
TABLE 1.1
DIAGNOSTIC CODES
1.3
ERROR CODES
When a code is flashing in the upper or lower LED display, the relevant burner has locked out and will need to be
reset by depressing the button on the water heater control panel. The following table gives a list of error codes,
descriptions of the causes. If an error code does not reset or occurs again immediately, a competent person
should be called to investigate and rectify the fault.
Code Fault
F0
Short circuit in ionisation circuit
F1
Blocked condensate drain
F2
High temperature limit exceeded
F4
Wrong fan speed
F5
No flame after 5 ignition attempts
F6
Flame lost (4 times) during running
E0
Outlet temperature sensor shorted or interrupted
E2
Inlet temperature sensor shorted or interrupted
E5
Flow temperature sensor shorted or interrupted
E6
Low water flow (A8) has occurred 4 times
PP
Parameters programmed into controller
PE
Incorrect parameters programmed into controller
nc
Heater control has failed
NC
Cascade communication has failed
H1
Gas valve wiring interrupted
TABLE 1.2
ERROR CODES
