Lennox XP14 Elite Series Installation Instructions Manual page 21

Actuation--When the reversing valve is de-energized,
the Y1 circuit is energized, and the coil temperature is
below 35°F (2°C), the board logs the compressor run time.
If the board is not calibrated, a defrost cycle will be initiated
after 34 minutes of heating mode compressor run time.
The control will attempt to self-calibrate after this (and all
other) defrost cycle(s).
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 6
hours of heating mode compressor run time has been
logged since the last defrost cycle.
NOTE - If ambient or coil fault is detected, the board will not
execute the TEST mode.
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.
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 as
illustrated in figure 25 for TEST operation.
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 two to five 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.
NOTE - The 30-second off cycle is NOT functional when
jumpering the TEST pins.
Short test pins for longer than 1
second but less than 2 seconds
Clear any short cycle lockout and
5 strike fault lockout function, if
applicable. No other functions will
be executed and unit will continue
in the mode it was operating.
Y1 Active ('O"line inactive) ]
I
i
Short test pins for more than 2 seconds
I If in COOLING Mode
Clear any short cycle lockout and 5 strike fault lockout
function, if applicable.
IIIf i n Mode I IIf i n Mode
No further test mode
operation will be executed
until the test short is
removed and reapp ed.
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.
The unit will terminate defrost
and enter Heat Mode
un-calibratedwith defrost timer
set for 34 minute test. No
further test mode operation will
be executed until the test short
is removed and reapplied.
Test pin short REMAINS in place for more than 5 seconds / Test short REMOVED before maximum
pins
a
of 5 seconds
The unit will return to Heat mode un-calibrated with defrost timer set for I
34 minutes. No further test mode operation will be executed until the test The unit will remain in Defrost mode until
short s removed and re apped, j termination on time or temperature
Figure 25. Test Mode
Page 21
XP14 SERIES