Lennox SLP98UHV Installation Instructions Manual page 39

Operation
Variable Capacity Heat
(35% to 100%)
Three-Stage Heat
(35%, 70%, 100%)
Two-Stage Heat (W1 70%, W2 100%)
NOTE - When the SLP98UHV is used with an icomfort
Toucht communicating thermostat, all indoor blower
speed selections and DIP switch settings are made by the
communicating thermostat.
SLP98UHV units are equipped with an integrated control.
This control manages ignition timing, combustion air induc­
er speed, heating mode fan off delays and indoor blower
speeds based on selections made using the icomfort
Toucht thermostat or the control DIP switches and on-
board links. The control includes an internal Watchguard
feature which automatically resets the ignition control
when it has been locked out.
NOTE - All DIP switches are factory shipped in the
"OFF" position.
Heating Operation DIP Switch Settings -- Figure 47
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 application.
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. See table 13.
Switch 2 -- Operating Mode with Two-Stage Thermo­
stat -- If a two-stage thermostat is used, the furnace can
operate in either variable-capacity or conventional two-
stage mode. When variable-capacity mode is selected, the
firing rate of the unit is varied to maximize comfort. Conven­
tional two-stage mode is the factory default setting. See
table 13.
Switch 3 -- Second-Stage Heat On Delay -- If a single-
stage thermostat is used, the integrated control can be
used to energize second-stage heat after either 7 minutes
or 12 minutes of first-stage heat operation. See table 13.
Switches 4 and 5 -- Blower-Off Delay -- The blower-on
delay of 30 seconds is not adjustable. The blower-off delay
(time that the blower operates after the heating demand
has been satisfied) can be adjusted by moving switches 4
TABLE 13
Thermostat Selection Switch Settings
Thermostat Switch 1
Two-Stage
Single-Stage
Two-Stage
and 5 on the integrated control. The unit is shipped from the
factory with a blower-off delay of 90 seconds. The blower-
off delay affects comfort and is adjustable to satisfy individ­
ual 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-energized. Longer off delay
settings provide lower supply air temperatures; shorter set­
tings provide higher supply air temperatures. Table 14 pro­
vides the blower-off timings that will result from different
switch settings.
Indoor Blower Operation DIP Switch Settings
Switches 6 and 7 -- Continuous Indoor Fan Operation­
Blower Speed -- The unit is shipped from the factory with
the DIP switches positioned for medium low (2) speed dur­
ing continuous indoor blower operation. The table below
provides the continuous blower speeds that will result from
different switch settings. Refer to tables beginning on page
42 for corresponding cfm values.
Continuous Indoor Blower Operation -- Blower Speeds
* Percentage of high speed cooling
Page 39
Switch 2
Off On
On Off
Off Off
TABLE 14
Blower-Off Delay Switch Settings
Blower-Off Delay
Switch 4
(Seconds)
60
90 (factory)
120
180
TABLE 15
Speed
1 - Low (28%)*
2 - Medium Low
(38%)* Factory
3 - Medium High
(70%)*
4 - High (100%)*
Switch 3
Off
2nd stage delay
OFF = 7 minutes
ON = 12 minutes
3rd stage delay
10 minutes fixed
Off
Switch 5
Off On
Off Off
On Off
On On
Switch 6 Switch 7
Off On
Off Off
On Off
On On