Friedrich 2003 Test, Thermostat SQ & KQ Models See Figure, Thermostat YQ Model Only See Figure

(QME Units) The Fan Speed button and the Warmer button. ( XQ Units) The Fan Speed button and the Temp Up button. The indoor temperature will be displayed for 10 seconds. The display will change back to the Set Point temperature by pressing any key button except for the On/Off button. The indoor temperature can be viewed in all modes, including test mode.

Filter Alert: The Filter Alert indicator turns on after the fan motor has been operating for 250 hours. The Filter Alert indicator is reset by pressing the Filter Alert button one time only,. Power failures will not reset the 250 hour timer. All time elapsed is stored in memory and resumes counting after power is restored.

Keep Alive: The electronic control has a memory to retain all functions and status as set up by the user in the event of a power failure. Once power is restored to the unit there is a two second delay before the fan comes on and approximately three minutes delay before the compressor is activated, providing that the mode was set for cooling and the set point temperature has not been met in the room.

Figure 31

Thermostat

(YQ Models Only)

TEST:

1.Remove leads from thermostat.

2.Turn thermostat knob clockwise to its coldest position.

3.Test for continuity between the two terminals. Contacts should be closed.

4.Turn thermostat knob counterclockwise to its warmest position.

THERMOSTAT ("SQ & KQ" Models) - See Figure 30.

Thermostat is used to cycle the compressor on and off at the comfort level desired. The thermostat has a range from 60° ±2°F to 90° ±4°F, with a differential of 5°F. Turning the knob clockwise lowers the indoor room temperature setting, while turning the knob counter clockwise raises the indoor temperature.

TEST:

Remove wires, turn thermostat to its coldest position. Check for continuity between the two terminals. Turn thermostat to warmest position, check continuity to see if contacts open. NOTE: Temperature must be in range listed to check thermostat.

Figure 30

Thermostat

THERMOSTAT ("YQ" Model Only) (See Figure 31)

This thermostat is single pole-double throw, cross ambient with a range of 60° to 92°F and a differential of ±2°F. Terminal "2" is common.

5.Test for continuity - contacts should be open.

NOTE: The thermostat must be within the temperature range listed to open and close.

To maintain the comfort level desired, a cross ambient type thermostat is used.The thermostat has a range from 65° ±2°F to 87° ±3°F. The thermostat bulb is positioned in front of the evaporator coil to sense the return air temperature. Thermo- stat malfunction or erratic operation is covered in the trouble- shooting section of this manual.

TEST:

1.Remove leads from thermostat.

2.Turn thermostat knob clockwise to its coldest position.

3.Test for continuity between the two terminals. Contacts should be closed.

4.Turn thermostat knob counterclockwise to its warmest position.

5.Test for continuity - contacts should be open.

NOTE: The thermostat must be within the temperature range listed to open and close.

THERMOSTAT - Models ES, YS, EM, YM, EL, YL (See Figure 32)

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 terminate 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 within a plastic block to supply a small amount of heat to the bulb area to prevent long "off cycles" in the "Cool-Fan Auto" (MoneySaver) position (see Figure 8.) A current feedback through the fan motor windings during "off cycle" completes the circuit to the resistor.

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