COMPONENTS TESTING
THERMOSTAT (“EQ08” Models) (See Figure 17)
This thermostat is single
Figure 17
Thermostat
(EQ Model)
WARNING
ELECTRIC SHOCK HAZARD
Disconnect power to the unit before servicing. Failure to follow this warning could result in serious injury or death.
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.
To maintain the comfort level desired, a cross ambient type thermostat is used. The thermostat has a range from 60° ±2°F to 92° ±3°F. The thermostat bulb is positioned in front of the evaporator coil to sense the return air temperature. Thermostat malfunction or erratic operation is covered in the troubleshooting section of this manual.
THERMOSTAT - Models ES, YS, EM, YM, EL, YL
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
In the heating cycle, the heat anticipator is energized to supply a small amount of heat during the “on” cycle. This will open the contacts in the thermostat prematurely to maintain a closer differential between the “cut in” and “cut out” temperature. The heat anticipator is energized in the heating mode regardless of whether fan is placed in the automatic (MoneySaver) or constant run position.
RANGE: | Thermostat Properties |
| 60°F (±2°) to 92°F (±2°) |
TEST:
Cooling/Heating Models: Remove wires from thermostat and check continuity between terminal “2” (common) and “3” for cooling. Check between terminals “2” (common) and “1” for heating. Also check that contacts in thermostat open after placing in either position. NOTE: Temperature must be within range listed to check thermostat. Refer to the troubleshooting section in this manual for additional information on thermostat testing.
THERMOSTAT ADJUSTMENT
No attempt should be made to adjust thermostat. Due to the sensitivity of the internal mechanism and the sophisticated equipment required to check the calibration, it is suggested that the thermostat be replaced rather than calibrated. Thermostat bulb must be straight to insure proper performance.
Figure 18
Thermostat
THERMOSTAT BULB LOCATION
The position of the bulb is important in order for the thermostat to function properly. The bulb of the thermostat should be located approximately 45° to a maximum of 60° from horizontal. Also, do not allow the thermostat bulb to touch the evaporator coil. (See Figures 17 and 18)
Figure 19
Thermostat Bulb Location
(EQ Model)
Thermostat sensor holder 020 to be positioned between the 4th and 5th and 6th and 7th rows of tubes from the bottom of the coil at dimension shown
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