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Troubleshooting – Lochinvar Shield SNA285-125 User Manual

Page 67

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67

13

Troubleshooting

(continued)

Table 13E (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Water Heater
Interface

FAULT

DESCRIPTION

CORRECTIVE ACTION

Service Blk

While the unit is in Service Mode, the outlet
temperature has exceeded 185°F.

• Establish a draw to remove HW heat from the

water heater.

• 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 6 - System Piping
for the proper piping methods for the Shield water
heater.

• Check 120 VAC to the water heater pump motor on

a call for heat. If voltage is not present, check the
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.

• Verify that the water heater pump is set to the proper

speed or that the water heater pump is the proper
size. Reference Section 6 - System Piping for water
heater pump specifications.

Low 24 VAC

120 VAC input to the main control board has
dropped below 80 VAC.

• Check 120 VAC supply to the transformer.

• Check wiring connections at the low voltage terminal

strip.

• Check the wire size/length to remote devices.

• Replace the transformer.

Watch Dog Error

The main control board has detected an
internal fault.

• Replace the main control board.

Write EEProm

The main control board has detected an
internal fault.

• Replace the main control board.

CRC Parameters

The main control board has detected an
internal fault.

• Replace the main control board.

Installation & Service Manual

TM