Form CP-MAPS-D12 with FX05, Page 18
AP – Air Proving - When the blower is called to be ON (point BO-1), the
blower starts, and the blower status switch must close proving blower opera-
tion. If the blowers status does not show blower operation within 180 seconds,
the unit shuts down. The unit must be restarted by cycling power to the FX05
controller or opening/closing the “Unit ON/OFF” switch (point BI-3).
During normal operation after initial blower startup, if the blower status input
shows open for more than three seconds, the unit will shut down cooling and
heating equipment. If the AP input continues to remain open for an additional
180 seconds, the blower is shutdown, and the FX05 controller will be in lockout
mode. The controller can be reset by cycling power to the FX05 controller or
toggling the BI-3 system on/off switch. If the blower status switch is made before
the unit reaches lockout mode, cooling and heating operation will restart.
Troubleshooting - A ashing AP is caused due to an open circuit on Ter-
minals 48 and 46. Check the air proving switch to ensure it is operational
(be sure the blower cabinet door is closed). If equipped with an Option
BF15 phase loss monitor (in the high voltage box), check the indicator
light. The green light indicates the unit is in phase. Red light indicates out
of phase. Recycle power to the unit to clear out the alarm.
FS – Low Limit Freeze Protection Lockout - When the blower is called
to be ON and the discharge air temperature is below the low limit freeze set-
point (LSP = 36°F) for 600 seconds, the unit is shutdown (blower OFF). The
display will ash “FS”. When the discharge air rises above the low limit freeze
setpoint plus 30°F, the low limit freeze lockout is disabled, allowing the unit to
operate. Three (3) consecutive lockouts within one hour will result in a con-
tinuous lockout state. The FX05 power must be cycled before operation can
continue. Toggling the BI-3 input will not reset the unit.
Troubleshooting - A ashing FS indicates the unit has encountered a
low discharge air temperature (below 36°F) for over 7 minutes. Inves-
tigate the heating system and recycle the power to clear out the alarm.
Verify that the gas valve is open and the heating board is operational.
Sensor Failures (ashing “ot” or “St”) - If a temperature sensor value
reads (999) or open circuit, the sensor is in a failed condition.
If the discharge air dry bulb sensor fails, the controller will lock out the unit. No
mechanical equipment will be allowed to run. The display will ash “St”. Install-
ing or replacing the sensor will allow immediate restarting of the equipment.
A failed outdoor air sensor (ashing “ot”) will lock out mechanical cooling and
heating operation. However, the blower will continue to operate.
Troubleshooting - A ashing St means the discharge air sensor may
not be connected (check for two white wires on terminals 54 and 57). To
check the sensor for failure, remove the two wires and check resistance
against temperature (See chart on page 21). Make sure that the sensor
is properly located in the ductwork.
A ashing “ot” means the outdoor air sensor may not be connected or
has failed. Check terminals 54 and 56 and sensor operation.
“EE” – Controller Low Voltage Lockout - If the FX05 controller power
drops below the minimum level, the display will read EE and all controller func-
tions will be OFF. The controller will restart when power level returns to nor-
mal.
Phase Loss Switch - No Display (Lockout) - (Option BF14 or BF15 is
required.) If the phase monitor detects a poor power condition, the phase loss
switch will cut power to the control circuit. The phase loss switch will automti-
cally reset when the poor power condition is no longer detected.
Alarm Displays
(cont’d)
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