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Troubleshooting – Lochinvar CREST 3 User Manual

Page 49

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3

Troubleshooting

(continued)

Table 3G (continued from previous page) Troubleshooting Chart - Fault Messages Displayed on Boiler Interface

FAULT

DESCRIPTION

CORRECTIVE ACTION

Blower Proving

Switch Open 2

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

Pressure switch contacts are open.

• Check the wiring connections to switch. Wires should
be connected to the common and normally open
terminals.
• Remove switch and check for blockage in the orifice.
• Vent/air intake lengths exceed the maximum allowed
lengths. Refer to Section 2 - General Venting of the
Crest Installation and Operation Manual for
proper lengths.
• Check for obstruction or blockage in the vent/air
intake pipes or at terminations.
• Inspect the burner. Reference page 34 of this manual
for removal and cleaning procedures. Replace if
necessary.
• Verify combustion air blower 2 is operating. Replace if
necessary.
• Inspect the heat exchanger. Reference page 35 of
this manual for removal and cleaning procedures.
• Faulty pressure switch. Replace switch.

Burner Supply

Temperature

Differential

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

Combustion air to burner 1 temperature
is higher than combustion air to burner 2
temperature or vice versa.

• Inspect the combustion air temperature sensor and
associated wiring.
• Measure the resistance of the combustion air
temperature sensor and compare to Table 3E on
page 38 of this manual
• Replace the sensor if necessary.
• Verify that the vent / air intake pipes are properly
installed and that there are no obstructions.

Burner Supply

Temperature

High 1

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

Combustion air temperature is very high.

• Check if the vent backflow preventer is installed for
boilers commonly vented.
• Check if the vent backflow preventer is stuck open
while the unit is off.
• Inspect the combustion air temperature sensor and
associated wiring.
• Measure the resistance of the combustion air
temperature sensor and compare to Table 3E on
page 38 of this manual.
• Replace the sensor if necessary.

Burner Supply

Temperature

High 2

(will require a manual

reset once the condition

has been corrected. Press

the RESET button on the

display to reset.)

Combustion air temperature is very high.

• Check if the vent backflow preventer is installed for
boilers commonly vented.
• Check if the vent backflow preventer is stuck open
while the unit is off.
• Inspect the combustion air temperature sensor and
associated wiring.
• Measure the resistance of the combustion air
temperature sensor and compare to Table 3E on
page 38 of this manual.
• Replace the sensor if necessary.

Service Manual

49

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