Thermostat - Friedrich YS09J10 Service & Parts Manual

Figure 7: SYSTEM CONTROL PANEL
(Heat Pump & Electric Heat Models)
7. "Lo Heat" Position - fan operates on low speed, com-
pressor or electric heater is on.
8. "Fan Only" Position - operates on medium speed.
NOTE: Heat pump models with electric heat - in the
heat position, heating element only will be en-
ergized when outdoor temperature is below the
operating range of the heat pump.
Figure 8: SYSTEM CONTROL SWITCH
(Heat Pump & Electric Heat Models)
TTJ-0198 (10/97)
SYSTEM CONTROL SWITCH - TEST
Disconnect leads from control switch. Turn control to
position being tested (see Figure 8.) There must be con-
tinuity as follows:
1. "Off" Position - no continuity between terminals.
2. "Lo Cool" Position - between terminals "C" and "3",
"C2" and "2", "LO" and "M/S", "AR" and "5".
3. "Med Cool" Position - between terminals "C" and
"3", "C2" and "2", "M" and "M/S", "AR" and "5".
4. "Hi Cool" Position - between terminals "C" and "3",
"C2" and "2", "H" and "M/S", "AR" and "5".
5. "Hi Heat" Position - between terminals "C" and "1",
"C2" and "4", "H" and "M/S", "AR" and "5".
6. "Med Heat" Position - between terminals "C" and
"1", "C2" and "4", "M" and "M/S", "AR" and "5".
7. "Lo Cool" Position - between terminals "C" and "1",
"C2" and "4", "LO" and "M/S", "AR" and "5".
8. "Fan Only" Position - between terminals "L1" and
"M".
THERMOSTAT - (see Figure 9)
A cross ambient thermostat is used on all heat pump
and electric heat units. In addition to cycling the unit in a
heating or cooling operation, the thermostat will termi-
nate the cooling cycle in the event ice forms on the
evaporator coil, in this case the thermostat functions as
a de-ice control. A resistor (anticipator) is positioned
Figure 9: THERMOSTAT
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