User Interface Display - Westinghouse WBCETNG750 Manual

D. User Interface Display
Cascade Control Fault Codes
Screen
SYS SUPPLY SENSOR E03
PUMP OFF 12:56P
FLUE TEMP ECO F01
PUMP ON 1:47P
Screen
SUPPLY SENSOR F02
PUMP ON TIME
RETURN SENSOR F03
PUMP ON TIME
Description
E03 indicates a problem with the system
sensor circuit. The circuit could be open or
shorted. Possible reasons for this error are:
There is no system sensor connected to the
Master Boiler.
The system sensor is faulty.
There is a short circuit in the system sensor
wiring; possibly from a staple placed through
the wire, or damage to the wire causing both
conductors to touch.
The system sensor wiring is open due to
defect or damage.
This code indicates that the Flue ECO has
tripped because the flue temperature has
o
exceeded 190 F. This switch has to be
manually reset.
Description
The dual supply sensor contains two
sensing elements within a single body. F02
indicates that one or both halves of the
supply temperature sensor has failed OR the
difference between the dual sensor readings
o
is greater than 18 F. This is a serious safety
issue and the boiler will not restart until the
sensor is replaced by a technician and he
pushes the RESET button on the display.
This situation is indicated by the red light on
the display and the flashing word LOCKOUT.
During this lockout fault, the pump will be on
as indicated on the second line of the display.
F03 indicates the return temperature sensor
of the boiler has failed. The boiler will not
restart until a technician replaces the sensor
and pushes RESET on the display. This is
a serious safety issue as indicated by the
illuminated red light and the word LOCKOUT
flashing on the display. During this lockout
fault, the pump will be on.
Possible Remedy
Disconnect the system sensor from the wiring and
measure it's resistance. Compare the measured resistance
to the table in this manual to see if it corresponds to the
temperature of the sensor. If the resistance does not
agree with the sensor, replace the sensor. If the sensor
is OK, disconnect the sensor wiring from both the boiler
and the sensor and check continuity using an ohmmeter.
Repair or replace as necessary.
If this error is present, the boilers in the cascaded group
will run and ignite simultaneously when there is a heat
demand. Each boiler will modulate to maintain set
point temperature on its own supply sensor. This code
automatically resets when repair is complete. This code
will not display if system setting function ERROR SYSTEM
SENS is set to OFF.
1. Push the reset button in the center of the switch body
to reset the switch.
2. Monitor the actual surface temperature of the heat
exchanger near the switch. If the switch trips again,
proceed with the steps below.
3. Disconnect the flue ECO on the rear of the heat
exchanger from the wiring and measure it's resistance.
Resistance should be at or near zero (0) ohms. If there is
infinite resistance (open circuit), replace the ECO.
4. If the ECO is OK, disconnect the switch wiring from
both the boiler and the ECO and check continuity of the
wiring using an ohmmeter. Repair or replace as necessary.
NOTE: The common reasons for temperature switches to
trip are a) low water flow through the boiler, b) poor heat
transfer from water to the load, or c) flue blockage.
5. Push RESET on the boiler. If the boiler tries to ignite or
ignites and only runs for a short time and the F01 code
returns, investigate the flue for blockage.
Possible Remedy
1. Check the electrical connections to each half of the
thermistor on the outlet manifold. Verify 5 VDC by
checking in Molex connector. If there is not 5 VDC, check
the harness. If harness and sensors are OK, replace
control.
NOTE: The boiler will reset automatically. Verify
thermistor resistance values of each half of the dual
sensor by referencing chart in this manual.
2. Replace thermistor if necessary.
1. Check circulator pump operation.
2. Ensure adequate flow through the boiler by accessing
the status menu and determining there is less than a 50
rise from the return thermistor to the supply thermistor.
3. Troubleshoot thermistor by following the steps in F02.
53
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F
WHL-038 Rev. 1.29.16