Lennox SL280UHNV Installation Instructions Manual page 32

Integrated Control DIP Switch Settings -
Conventional Thermostat (non-communicating)
SL280UHNV units are equipped with a two-stage, vari-
able speed integrated control. This control manages igni-
tion timing, heating mode fan off delays and indoor blower
speeds based on selections made using the control dip
switches and jumpers. The control includes an internal
watchguard feature which automatically resets the ignition
control when it has been locked out. After one hour of con-
tinuous thermostat demand for heat, the watchguard will
break and remake thermostat demand to the furnace and
automatically reset the control to relight the furnace.
Note: All communicating settings are set at the thermo-
stat. See thermostat installation instruction. In a commu-
nication system all DIP switch and clippable link settings
are ignored. For conventional thermostats proceed with
DIP switch and clippable link settings as outlined in the
following.
Heating Operation DIP Switch Settings
Switch 1 -- Thermostat Selection -- This unit may be
used with either a single-stage or two-stage thermostat.
The thermostat selection is made using a DIP switch
which must be properly positioned for the particular appli-
cation. The DIP switch is factory-positioned for use with a
two-stage thermostat. If a single-stage thermostat is to be
used, the DIP switch must be repositioned.
• Select "OFF" for two-stage heating operation controlled
by a two-stage heating thermostat (factory setting);
• Select "ON" for two-stage heating operation controlled
by a single-stage heating thermostat. This setting pro-
vides a timed delay before second-stage heat is initi-
ated.
Switch 2 -- Second Stage Delay (Used with Single-
Stage Thermostat Only) -- This switch is used to de-
termine the second stage on delay when a single-stage
thermostat is being used. The switch is factory-set in the
OFF position, which provides a 7-minute delay before
secondstage heat is initiated. If the switch is toggled to
the ON position, it will provide a 12-minute delay before
secondstage heat is initiated. This switch is only activated
when the thermostat selector jumper is positioned for sin-
gle-stage thermostat use.
Switches 3 and 4 -- Blower-Off Delay -- The blower-on
delay of 30 seconds is not adjustable. The blower-off de-
lay (time that the blower operates after the heating de-
mand has been satisfied) can be adjusted by moving
switches 3 and 4 on the integrated control. The unit is
shipped from the factory with a blower-off delay of 90 sec-
onds. The blower off delay affects comfort and is adjust-
able to satisfy individual applications. Adjust the blower
off delay to achieve a supply air temperature between 90°
and 110°F at the exact moment that the blower is de-en-
ergized. Longer off delay settings provide lower supply air
temperatures; shorter settings provide higher supply air
temperatures Table 9 provides the blower off timings that
will result from different switch settings.
Blower Off Delay Switch Settings
Blower Off Delay
Seconds
60
90 (factory)
120
180
Indoor Blower Operation DIP Switch Settings
Switches 5 and 6 -- Cooling Mode Blower Speed -- The
unit is shipped from the factory with the dip switches po-
sitioned for high speed (4) indoor blower motor operation
during the cooling mode. Table 10 provides the cooling
mode blower speeds that will result from different switch
settings. Switches 5 and 6 set the blower cfm for second-
stage cool. The integrated control automatically ramps
down to 70% of the second-stage cfm for first-stage cfm.
Refer to tables for corresponding cfm values.
Speed
Low
Medium Low
Medium High
High (factory)
Switches 7 and 8 -- Cooling Blower Speed Adjustment
-- The unit is shipped from the factory with the dip switches
positioned for NORMAL (no) adjustment. The dip switches
may be positioned to adjust the blower speed by +10%
or -10% to better suit the application. Table 11 below pro-
vides blower speed adjustments that will result from differ-
ent switch settings. Refer to tables for corresponding cfm
values.
Adjustment
+10% (approx)
Factory Default
-10% (approx)
Switches 9 and 10 -- Cooling Mode Blower Speed
Ramping -- Blower speed ramping may be used to en-
hance dehumidification performance. The switches are
factory set at option A which has the greatest effect on de-
humidification performance. Table 12 provides the cooling
model blower speed ramping options that will result from
different switch settings. The cooling mode blower speed
ramping options are detailed on the next page.
NOTE - The off portion of the selected ramp profile also
applies during heat pump operation in dual fuel applica-
tions.
Page 32
TABLE 9
Switch 3 Switch 4
On Off
Off Off
Off On
On On
TABLE 10
Switch 5 Switch 6
On On
Off On
On Off
Off Off
TABLE 11
Switch 7 Switch 8
On Off
Off Off
Off Off