Thermo Pride CHX3-75N Installation And Operation Manual page 39

All installations and services must be performed by qualified service personnel.
3. THERMOSTAT CONNECTIONS AND ANTICIPATOR SETTING
NOTICE: For two-stage thermostat wire connectors see wire diagram page 59.
For single-stage thermostat with two-stage operation connect W from thermostat to W1 on control. W2
on control board is not used. Thermostat dip switches S7-1 & S7-2 on control board (Fig. 21) will need to
set at the desired setting per (Table 4B). In this configuration the furnace will light and burn on low fire. If
thermostat has not been satisfied in set delay time for second stage the control will step up to high fire
until thermostat is satisfied. The auto setting will allow the control to calculate the delay for second stage
based on demand. The average calculated duty cycle chart below (Table 4A) shows how the control
calculates staging based on demand.
Proper control of the indoor temperature can only be achieved if the thermostat is calibrated to the
heating and/or cooling cycle. A vital consideration of this calibration is related to the thermostat heat
anticipator.
The proper thermostat heat anticipator setting is 0.4 AMPS for furnace operation only. To increase length
of cycle, increase setting of heat scale; to decrease length of cycle, decrease setting of heat scale.
Anticipators for the cooling operation are generally pre-set by the thermostat manufacturer and require no
adjustment.
Anticipators for the heating operation are of two types, pre-set and adjustable. Those that are pre-set will
not have an adjustment scale and are generally marked accordingly.
Table 4A
Average
Calculated
Duty Cycle % or is less Low to High
Equals than Stage Delay
0 38
38 50
50 62
62 75
75 88
88 100
Demand
12 Min Light
10 Min Light to Average
7 Min Average
5 Min Average to Heavy
3 Min Heavy Light
1 Min Heavy
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