Lennox Elite Series Installation Instructions Manual page 25

Short test pins for longer than
1 second but less than 2.0
seconds
Clear any short cycle
lockout and/or 5-strike
fault lockout function, if
applicable. No other func-
tions will be executed and
unit will continue in the
mode it was operating,
1
Y1 Active ("0" line inactive) /
/
I
Short test pins for more than 2.0 seconds
I If in COOLING Mode
Clear any short cycle lockout or 5-strike fault lock-
out function, if applicable.
i
If in HEATING Mode I I If in DEFROST Mode
No further test
mode operation will
be executed until
the test short is re-
moved and reap-
plied.
The controller will check for ambient and coil
faults (open or shorted) If a fault exists, the
unit will remain in Heat Mode and no further
test mode operation will be executed until the
test short is removed and re applied. If no
fault exists, the unit will go into Defrost mode.
I
The unit will terminate defrost and
enter Heat Mode uncalibrated with
defrost timer set for 34 minute
test. No further test mode opera-
tion will be executed until the test
short is removed and reapplied.
Test pin short REMAINS in place for more than 5 seconds
t
The unit will return to Heat mode uncalibrated with defrost timer set for
34 minutes. No further test mode operation will be executed until the
test short is removed and re applied.
Test pins short REMOVEDof 5 secondsbef°re a maximum
The unit will remain in Defrost mode until ter-
mination on time or temperature
Figure 40. Test Mode
Calibration success depends on stable system
temperatures during the 20-minute calibration period. If
the board fails to calibrate, another defrost cycle will be
initiated after 90 minutes of heating mode compressor run
time. Once the defrost board is calibrated, it initiates a
demand defrost cycle when the difference between the
clear coil and frosted coil temperatures exceeds the
maximum difference allowed by the control or after six
hours of heating mode compressor run time has been
logged since the last defrost cycle.
Termination--The defrost cycle ends when the coil
temperature exceeds the termination temperature or after
14 minutes of defrost operation, If the defrost is terminated
by the 14-minute timer, another defrost cycle will be
initiated after 34 minutes of run time,
Test Mode--When Y1 is energized and 24V power is
being applied to the board, a test cycle can be initiated by
placing the termination temperature jumper across the
"Test" pins for 2 to 5 seconds, If the jumper remains across
the "Test" pins longer than five seconds, the control will
ignore the test pins and revert to normal operation, The
jumper will initiate one cycle per test,
Enter the TEST mode by placing a shunt (jumper) across
the TEST pins on the board after power-up. (The TEST
pins are ignored and the test function is locked out if the
shunt is applied on the TEST pins before power-up). Board
timings are reduced, the low-pressure switch is ignored
and the board will clear any active lockout condition,
Each test pin shorting will result in one test event. For
each TEST the shunt (jumper) must be removed for at
least one second and reapplied, Refer to flow chart (figure
40) for TEST operation,
Note: The Y1 input must be active (ON) and the 0 room
thermostat terminal into board must be inactive.
DEFROST BOARD DIAGNOSTICS
See table 12 on page 24 to determine defrost board
operational conditions and to diagnose cause and solution
to problems,
kWARNING
Before the start of each heating and cooling season, the
following service checks should be performed by a
qualified service technician. First, turn off electrical power
to the unit prior to performing unit maintenance.
• Inspect and clean the outdoor and indoor coils. The
outdoor coil may be flushed with a water hose.
NOTE - It may be necessary to flush the outdoor coil
more frequently if it is exposed to substances which
are corrosive or which block airflow across the coil
(e.g., pet urine, cottonwood seeds, etc.)
• Visually inspect the refrigerant lines and coils for leaks.
• Check wiring for loose connections.
• Check voltage at the indoor and outdoor units (with
units operating).
• Check the amperage draw at the outdoor fan motor,
compressor, and indoor blower motor. Values should
be compared with those given on unit nameplate.
• Check, clean (or replace) indoor unit filters.
• Check the charge and gauge the system pressures.
Page25
XP16 SERIES