Thermo Pride CHX3-75N Installation And Operation Manual page 41

All installations and services must be performed by qualified service personnel.
Modifications to ECM blower speed settings are done using the S3 and S4 dip switch controls. Thermo
Pride two-stage furnaces are factory shipped at the CFM settings listed below in Table 4C.
Control Board
Unit Dip Switch
Settings
SW3 1-4 Off
CDX3-75 SW4 1-3 Off
SW4 4 On
SW3 1-4 Off
CHX3-75
SW4 1-4 Off
SW3 1-4 Off
CDX3-100 SW4 1-3 Off
SW4 4 On
SW3 1-4 Off
CHX3-100
SW4 1-4 Off
SW3 1-4 Off
CDX3-125 SW4 1-3 Off
SW4 4 On
SW3 1-4 Off
CHX3-125
SW4 1-4 Off
For adjustments to the Cooling CFM settings, as well as all additional CFM changes, please reference
the dip switch tables listed in the ECM operation manual. (Included with every furnace.)
5. DE-HUMIDIFICATION
The ECM motor in conjunction with the W/R 50V51-843 has a feature to enhance de-humidification in the
cooling mode. In the dehumidify mode the indoor blower motor (ECM) reduces CFM. By reducing airflow
the indoor coil runs colder and thus extracts more moisture from the air.
The W/R 50V51-843 is shipped from the factory with dipswitch S5-2 set to on for system that do not have
a dehumidification connection from the thermostat. For systems using a thermostat that provides
dehumidification option move dip switch S5-2 to "OFF". With the S5-2 switch in the "OFF" position the air
conditioning fan speed will be reduced 30% from the normal CFM setting when the humidity in the home
is higher than the set point of the dehumidistat.
6. FIELD WIRING AND REPLACING WIRING
Field wiring between the furnace and devices not attached to the furnace shall conform with the
temperature limitation for Type T wire[63°F rise (35°C)] when installed in accordance with the
manufacturer's instructions. If any of the original factory supplied furnace wiring is replaced or a separate
device other than the thermostat is wired internal to the unit 105°C thermoplastic or equivalent wire must
be used.
2-Stage Blower Settings (from factory)
Table 4C
Heating
CFM
(low fire)
885
760
1094
1015
1366
1270
35
Heating
Constant Fan
CFM
CFM
(high fire)
1012 500
931 500
1340 600
1243 600
1673 700
1556 700
Cooling
CFM
1000
1000
1200
1200
1400
1400