Giant UGC55S-100 Installation & Maintenance Manual page 48

CODE DESCRIPTION
High temperature switch
F00 limit exceeded 194
o
(90 C).
Vent temperature limit
F01
exceeded.
Interrupted or shorted
F02 upper temperature
sensor.
Interrupted or shorted
F03
lower temperature sensor.
Upper temperature sensor
F05
o
exceeds 194 F (90
Lower temperature sensor
F06
o
exceeds 194 F (90
No flame detected –
Heater will make three (3)
attempts at ignition before
F09
the control goes into this
lockout condition. Will
reset in one (1) hour.
Loss of flame signal – The
heater will relight four (4)
times before the control
F10
goes into this lockout
condition. Will reset in one
(1) hour.
False flame signal – The
heater will lock out if it
senses a flame signal
F11F
when there should be
none present.
Combustion fan speed
incorrect – The heater will
lock out if it senses that
F13
the fan speed is less than
70% of expected rate for
more than 60 seconds.
Table 15 -
NOTE: If you replace a part to remedy a fault, it is recommended that you cycle the unit at least three or four times
to assure the fault has been resolved.
GI-IM048En-1013
926 CONTROL BOARD FAULT
1. Try reset. If F00 repeats, create a demand for hot water. (DANGER: Use caution to prevent burn injury.) If
o
water is above 194 F (90
chart, this section.) Replace bad sensor. If water is below 194
with ohmmeter. Switch should be closed at this point. If not, replace switch.
o
F
2. If unit did reset successfully, let the heater run and go into the status menu to check the upper and lower
temperature sensor. If either reading displayed does not make sense, check appropriate sensor with
ohmmeter. (Refer to resistance chart, this section.) Replace bad sensor. Do an OHMs reading on both sensors
to check continuity.
1. Inspect all flue piping. If the flue is damaged or shows signs of overheating, repair or replace the flue parts
as necessary before proceeding.
2. If the flue piping system is intact, not damaged and there is no sign of the flue overheating (such as
discoloration or melting), push the red reset button on the flue switch
3. Be sure the heater is connected to a water supply and full of water.
4. Push the RESET button on the heater control panel. The water heater should light. If the water heater lights,
proceed to step 5. If the water heater does not light and the display again begins to flash F01, inspect the
wiring to the flue switch, repairing or replacing as necessary. If the wiring is intact, replace the flue switch, using
care to mount the new flue switch in the same position and mounting holes as the old one. If the display flashes
a code other than F01, follow the troubleshooting guide for that code.
5. Observe operation for five (5) minutes. Place the probe of an exhaust analyzer into the flue system within six
(6) feet (1.8 m) of the heater. The exhaust temperature should not rise above 190
minutes of operation.
6. If the flue temperature is below 190
the flue switch, using care to mount the new flue switch in the same position and mounting holes as the old
one. If the display flashes a code other than F01, follow the troubleshooting guide for that code.
7. If the flue temperature increases to over 190
1. Check the electrical connection to the appropriate temperature sensor.
2. If connection is okay, replace bad sensor.
1. If water in tank is not greater than 194
o
C). 2. If wiring is okay, check appropriate sensor with ohmmeter and compare to reading in resistance chart above.
If reading does not agree with water temperature, replace bad sensor.
o
C).
1. Watch the igniter through the observation window provided.
2. If there is no spark, check the spark electrode for the proper ¼" (6.3 mm) gap.
3. Remove any corrosion from the spark electrode and flame rectifier probe.
4. If there is a spark but no flame, check the gas supply to the heater.
5. If there is a flame, check the flame sensor.
6. Check any flue blockage or condensate blocks.
1. Monitor the gas pressure to the unit while in operation.
2. Assure that the flame is stable when lit.
3. Check to see if the green light on the display module is out while the heater is running.
4. If the green light doesn't come on or goes off during operation check the flame signal on the status menu.
5. If the signal reads less than 1 microampere, clean the flame rectifier probe.
6. If the flame rectifier probe continues to read low, replace it.
1. Turn the gas off to the unit at the service valve.
2. If the flame signal is still present replace the igniter.
3. If the flame signal is not present after turning off the gas supply, check the gas valve electrical connection.
4. If there is no power to the gas valve, remove the valve and check for obstruction in the valve seat or replace
the gas valve.
5. Turn the gas on at the service valve after corrective action is taken.
1. Check the combustion air fan wiring.
2. Replace the combustion air fan.
3. Replace the control board.
REMEDY
o
C), test upper and lower temperature sensor with an ohmmeter. (Refer to resistance
o o
F (88 C) and the heater again goes into lockout displaying F01, replace
o o
F (88 C), consult GIANT for further assistance.
o o
F (90 C), check wiring. Repair if faulty.
o o
F (90 C), test high temperature switch and wiring
o
F (88
48
o
C) after several