Lochinvar Shield SWR125 Installation & Service Manual page 73

12
Troubleshooting
Table 12F (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Water Heater Interface
FAULT
The outlet water temperature has exceeded
OUTLET ARHL
the setting of the automatic reset high limit.
AIR PRESSURE
SWITCH
(will require a manual
Air pressure switch contacts are open.
reset once the condition
has been corrected.
Press the RESET button
on the display to reset.)
BLOCKED
Thermal fuse on heat exchanger has opened.
DRAIN
AUX LIMIT
Aux limit device open.
FAULT
(continued)
DESCRIPTION
Installation & Service Manual
CORRECTIVE ACTION
• Adjust the set point of the auto reset limit to a higher
setting up to a maximum of 200°F. Reference Section
10 - Operating Information for adjusting procedures.
• 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.
• If the optional manual reset high limit has tripped,
check setting of the device.
• 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 the wiring connections to switch. Wires should
be connected to the common and normally closed
terminals.
• Air intake lengths exceed the maximum allowed
lengths. Refer to Section 2 - General Venting
for proper lengths.
• Check for obstruction or blockage in the air
intake pipes or at terminations.
• Check reference hoses connected to the air pressure
switch for blockage or obstruction.
• Inspect the burner. Reference page 66 of this manual
for removal and cleaning procedures. Replace if
necessary.
• Inspect the heat exchanger. Reference page 66 of
this manual for removal and cleaning procedures.
• Faulty air pressure switch. Replace switch.
• Check the wiring connections to the fuse on the heat
exchanger.
• Check continuity across the thermal fuse. If open,
replace heat exchanger.
• Check wiring to aux limit device.
• Check aux limit device.
Replace
73