Low Heat Blower Speeds; High Heat Blower Speeds - Lennox G71MPP SERIES Unit Information

TABLE 20

Low Heat Blower Speeds

Blower
Thermostat Speed
Demand Adjust-
ments
+15%
+7.5%
Low Heat
Normal
(R to W1)
−7.5%
−15%
Switches 14 through19 −− Heating Mode Blower Speed
−− Switches 14 through 19 are used to select heating mode
blower motor speeds. These switches are factory set at the
OFF position which provides 100 % of normal speed during
HIGH HEAT demand, 70% of normal speed during MID−
RANGE HEAT demand and 40% of normal speed during
LOW HEAT demand. Switches 14, 15 and 16 are used to
adjust the LOW FIRE blower motor speed. Switches 17, 18
and 19 are used to adjust the HIGH FIRE blower motor
speed. Figure 6 and tables 20 and 21 provides the heating
mode blower speeds that will result from different switch
settings. Figure 6 indicates the effect the DIP switch set-
tings (tables 20 &21 above) have upon the heating airflow
at various furnace firing rates.
Refer to tables 1 through 11 for corresponding cfm values.
Airflow Determination
S Identify blower speed adjustment points at low and high fire
S Airflow will lie on straight line between these two points and will fall within
the shaded area as shown
EXAMPLE −7.5% at low fire +7.5% at high fire
Increasing
Low Fire
Airflow
Dip Switches
14, 15, 16
+15%
+7.5%
Nominal
−7.5%
−15%
40%
DIP SWITCH SETTINGS
14 15 16
On Off On
On Off Off
Off Off Off
On On Off
On On On
60%
50%

High Heat Blower Speeds

Thermostat
Demand
High Heat
(R to
W1 & W2)
70% 80%
RATE (%)
FIGURE 6
Page 22
TABLE 21
Blower
DIP SWITCH SETTINGS
Speed
Adjust-
17 18
ments
+15% On Off
+7.5% On Off
Normal Off Off
−7.5% On On
−15% On On
High Fire
Dip Switches
17, 18, 19
100%
90%
19
On
Off
Off
Off
On
+15%
+7.5%
Nominal
−7.5%
−15%