3 Troubleshooting (continued)
Service Manual
Table 3G Troubleshooting Chart - Fault Messages Displayed on Boiler Interface
FAULT DESCRIPTION CORRECTIVE ACTION
Gas Pressure SW
Open
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
SMART TOUCH display
to reset.)
Either the low gas pressure switch or the high
gas pressure switches tripped.
• Measure the supply gas pressure to determine cause
of failure. Natural gas pressures should be between
4 inches w.c. (1.0 kPa) and 14 inches w.c. and LP gas
pressures should be between 8 inches w.c. (1.99 kPa)
and 14 inches w.c. (3.5 kPa).
• Refer to Section 6 - Gas Connections of the
Crest Installation and Operation Manual for detailed
information concerning the gas supply.
• Correct the supply gas pressure if necessary.
Low Water
Cutoff Open
(will require a manual
reset once condition has
been corrected. Press
the RESET button on the
SMART TOUCH display
to reset.)
The low water cutoff is not making.
• Reset the LWCO from the RESET button on the front
control panel.
• Verify system is full of water and all air has been
purged from the system.
• Check for loose or misplaced jumpers if flow switch or
LWCO is not installed.
Blown fuse. • Replace fuse F2 on the control board.
Blocked Drain SW
Open
(will require a manual
reset once condition has
been corrected. Press
the RESET button on the
SMART TOUCH display
to reset.)
The blocked drain switch has detected
excessive condensate build up inside the
unit.
• Check condensate tube from unit to floor drain for
proper installation and obstructions.
• Inspect condensate trap for blockage. Clean if
necessary.
• Check for loose wiring connection at wire harness
plug.
• Bad blocked drain switch. Replace switch.
APS
Open
(will require a manual
reset once the condition
has been corrected. Press
the RESET button on the
SMART TOUCH display
to reset.)
Blocked flue/inlet pressure switch contacts
are open.
• Check the wiring connections to switch. Wires should
be connected to the common and normally closed
terminals.
• 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.
• Check reference hose and tubing connected to the
pressure switch for blockage or obstruction.
• Inspect the burner. Reference this manual for removal
and cleaning procedures. Replace if necessary.
• Inspect the heat exchanger. Reference this manual
for removal and cleaning procedures. Replace if
necessary.
• Faulty air pressure switch. Replace switch.
• Verify combustion air blower is operating. Replace if
necessary.
• Check/replace filter.
45
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