Lochinvar Shield SWR125 Installation & Service Manual page 75

12
Troubleshooting
Table 12F (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Water Heater
Interface
FAULT
FLUE TEMP
The stack temperature has exceeded the
LIMIT
Flue Temp Limit set parameters.
FLUE TEMP
The stack temperature has exceeded the set
HIGH
parameters for the water heater.
OUTLET MRHL
(will require a manual
reset once the condition The outlet water temperature has exceeded
has been corrected. the setting of the manual reset high limit.
Press the RESET button
on the display to reset.)
OUTLET TEMP
Outlet water temperature has exceeded the
HIGH
maximum outlet water temperature.
OUTLET TEMP
DIFF
(will require a manual
The temperature difference between the two
reset once the condition
(2) outlet sensors is too high.
has been corrected.
Press the RESET button
on the display to reset.)
FLUE SENSOR
FAULT
(will require a manual
One or both of the flue sensors is open or
reset once the condition
shorted.
has been corrected.
Press the RESET button
on the display to reset.)
(continued)
DESCRIPTION
Installation & Service Manual
CORRECTIVE ACTION
• Inspect the heat exchanger. Reference page 66 of
this manual for the procedure on how to clean the flue
side of the heat exchanger.
• Inspect the flue sensor and associated wiring.
Measure the resistance of the flue sensor and
compare to Table 12D on page 70 of this manual.
Replace the sensor if necessary.
• Verify that the vent/air intake pipes are properly
installed and that there are no obstructions.
• Replace the main control board.
• Verify that the system is full of water and that all air
has been properly purged from the system.
• Verify that the water heater is piped properly into the
heating system. Refer to Section 5 - System
Piping for the proper piping methods for the Shield
water heater.
• Check 120 vac to water heater pump motor on a call
for heat. If voltage is not present, check wiring back
to the main control board.
• Replace the main control board if necessary.
• If 120 vac is present on a call for heat and the water
heater pump is not operating, replace the pump.
• If operating on something other than an outlet sensor,
check temperature setting of the main control board.
• Check resistance of water sensors and compare to
Table 12C on page 70 of this manual.
sensor if necessary.
• Check operation of diverter valve motor. Replace if
necessary.
• Check wiring to sensor.
connected and not damaged.
wiring if necessary.
• Measure the resistance of the sensor and compare to
the resistance in Table 12C on page 70 of this manual.
Replace sensor if necessary.
• Replace control module.
• Inspect the flue sensor and associated wiring.
Measure the resistance of the flue sensor and
compare to Table 12D on page 70 of this manual.
Replace the sensor if necessary.
• Replace the main control board.
Replace
Make sure wiring is
Reconnect / repair
75