Lockout modes
Note:
If the microprocessor board is flashing a system
warning and the unit is locked out and not running
the lockout can be cleared from the microprocessor
by a momentary shut down of incoming line voltage
(208VAC, 230VAC or 277 VAC). A lockout that still
occurs after line voltage shut-down means that the
fault still exists and needs to be repaired.
High pressure lockout (HP)
The high pressure lockout will occur if the discharge
pressure of the compressor exceeds 600 psig. The
lockout is immediate and has no delay from the
time the high pressure switch opens to the lockout.
Upon lockout the compressor will be de-energized
immediately. The blower will be de-energized fifteen
seconds after the compressor is de-energized.
Low pressure lockout (LP)
The low pressure lockout will occur if the suction
pressure falls below 40 psig for thirty continuous
seconds. The compressor will then be de-energized
and the blower will de-energize fifteen seconds after
the compressor is de-energized.
Freeze protection 1 lockout
The freeze protection 1 lockout will occur if the H
2
0
line temperature falls below the set point (15 °F or
30 °F) for thirty continuous seconds. See dip switch 2
described on page 23. The compressor will then be
de-energized and the blower will de-energize fifteen
seconds after the compressor is de-energized.
Freeze protection 2 lockout
The freeze protection 2 lockout will occur if the air coil
temperature falls below the set point 32 °F for thirty
continuous seconds. See dip switch 2 described on
page 23. The compressor will then be de-energized
and the blower will de-energize fifteen seconds after
the compressor is de-energized.
Condensate overflow 1 lockout (CO1)
The unit contains one condensate overflow sensor,
located in the chassis drain pan below the air coil. A
condensate lockout will occur if the sensor senses
condensate for thirty continuous seconds. The
compressor will then be de-energized and the blower
will de-energize fifteen seconds after the compressor
is de-energized.
Over/under voltage protection
If the unit control voltage is 18VAC>voltage>30VAC
the unit will shut down all inputs immediately. Once
the voltage has reached acceptable levels the unit
microprocessor will power “on” automatically and
resume previous operation.
Leaving water temperature (LWT)
sensor failure
If the leaving water temperature thermistor fails it will
not affect the operation of the unit. This sensor is for
monitoring purposes only.
Discharge air temperature (DAT)
sensor failure
If the discharge temperature thermistor fails it will not
affect the operation of the unit. This sensor is for
monitoring purposes only.
Freeze protection 1 temperature sensor
failure (FP1)
If the freeze protection 1 thermistor fails for thirty
continuous seconds, FP1 lockout will occur. The
compressor will then be de-energized and the blower
will de-energize fifteen seconds after the compressor
is de-energized. The sensor must be replaced if this
lockout occurs.
Freeze protection 2 temperature sensor
failure (FP2)
If the freeze protection 2 thermistor fails for thirty
continuous seconds, FP1 lockout will occur. The
compressor will then be de-energized and the blower
will de-energize fifteen seconds after the compressor
is de-energized. The sensor must be replaced if this
lockout occurs.
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