Thermostat - TM-5-4120-282-130045

42. Thermostat (figures 1 and 4)

a. Removal.

Remove left-side panel (para 39).

(1)

(2) Remove all front knobs from the thermostat, selector switch,

and fresh air control - loosen set screw from each.

Remove three screws from front name plate.

(3)

(4) Remove the two mounting screws from the thermostat and remove

from tie panel.

(5) Disconnect the wires from the thermostat and remove from the

unit.

Cleaning and Inspection.

(1) Clean the thermostat switch with a cloth dampened with clean-

ing fluid.

(2) Inspect the thermostat for damage and loose terminals.

(3) Repair or replace a defective thermostat.

c. Testing.

(1) Connect leads of a multimeter to the terminals of the thermo-

stat. Set meter on resistance.

(2) If the space temperature is above the thermostat setting, the

contacts will be closed and show a low reading on the multimeter.

(3) If the space temperature is below the thermostat setting, the

contacts will be open and a high resistance reading will show on the

meter.

(4) If the contacts are shown as open, put the thermostat on a

temperature above 80F. and after 15 minutes the thermostat contacts

should close; if not, the thermostat is defective.

(5) Replace a defective thermostat.

d. Installation.

(1) Connect the wires to the thermostat.

(2) Position the thermostat switch on the panel with two mounting

screws.