Lennox SLP99UHV Series Unit Information page 27

On-Board Link W914 DS to R (FIGURE 4)
On-board link W914, is a clippable connection between
terminals DS and R on the integrated control. W914 must
be cut when the furnace is installed with either the ZSV
variable zoning system or a thermostat which features
humidity control. If the link is left intact the PWM signal
from the ZSV control will be blocked and also lead to con-
trol damage. Refer to TABLE 15 for operation sequence
in applications including SLP99UHV, a thermostat which
features humidity control and a single-speed outdoor unit.
TABLE 16 gives the operation sequence in applications
with a twospeed outdoor unit.
On-Board Link W951 R to O (FIGURE 4)
On-board link W951 is a clippable connection between
terminals R and O on the integrated control. W951 must
be cut when the furnace is installed in applications which
include a heat pump unit and a thermostat which features
dual fuel use. If the link is left intact, terminal "O" will re-
main energized eliminating the HEAT MODE in the heat
pump.
On-Board Link W915 Y1 to Y2 (FIGURE 4)
On-board link W915 is a clippable connection between
terminals Y1 and Y2 on the integrated control. W915 must
be cut if two-stage cooling will be used. If the link is not cut
the outdoor unit will operate in second-stage cooling only.
Diagnostic LED (FIGURE 4)
The seven-segment diagnostic LED displays operating
status, target airflow, error codes and other information.
TABLE 14 lists diagnostic LED codes.
Diagnostic Push Button (FIGURE 4)
The diagnostic push button is located adjacent to the sev-
ensegment diagnostic LED. This button is used to enable
the Error Code Recall mode and the Field Test mode.
Press the button and hold it to cycle through a menu of
options. Every five seconds a new menu item will be dis-
played. When the button is released, the displayed item
will be selected. Once all items in the menu have been
displayed, the menu resumes from the beginning until the
button is released.
Error Code Recall Mode
Select "E" from the menu to access the most recent 10
error codes. Select "c" from the Error Code Recall menu
to clear all error codes. Button must be pressed a second
time while "c" is flashing to confirm command to delete
codes. Press the button until a solid "≡" is displayed to exit
the Error Code Recall mode.
Field Test Mode
Use the diagnostic push button to scroll through the menu
as described above. Release the button when the LED
flashes "-" to select the Field Test mode.
While in the Field Test mode the technician can:
• Initiate furnace ignition and move to and hold low-
fire rate by applying a R to W1 jumper.
• Initiate furnace ignition sequence and move to and
hold high-fire rate by applying a jumper from R to
W1 and W2.
• Initiate furnace ignition sequence and move to and
hold mid-fire rate by applying a jumper to R and
W2.
• Apply then remove the jumper from R to W1 and
W2 to change the firing rate from low fire to mid fire
and high fire.
• A vent calibration sequence can be initiated even if
a thermostat signal is not present. Press and hold
the push button until a solid "C" is displayed. Re-
lease the button and calibration will begin. The fur-
nace will perform the high-fire and low-fire pressure
switch calibrations and display "CAL". After calibra-
tion, the LED will return to the flashing "-" display.
During Field Test mode operation, all safety switches are
still in the circuit (they are not by-passed) and indoor blow-
er performance and timings will match DIP switch selec-
tions. Current furnace firing rate, indoor blower CFM and
flame signal will be displayed. To exit the Field Test mode,
press and hold the button. The menu will resume from the
beginning. Also, cycle the main power to exit the Field Test
mode. The integrated control will automatically exit the
Field Test mode after 45 minutes of operation.
Soft Disable
Soft disabling is when thermostat finds a device on the
BUS that it does not recognize and the thermostat sends
a the device a message to be in soft disabling mode until
properly configured. Two horizontal bars will display.
Steps to follow if the damper control module is displaying
the soft disable code.
1 - Confirm proper
(thermostat, damper control module, indoor and
outdoor).
2 - Cycle power to the control that is displaying the soft
disable code.
3 - Put the room thermostat through set up.
4 - Go to setup / system devices / thermostat / edit
/ then push reset.
5 - Go to setup / system devices / thermostat / edit /
then push resetAll.
Page 27
wiring between all devices