User Guide

Figure-9

1. Insert the blade of the tool or screwdriver between the

switchover plunger and the switchover lever shown in

Figure-8. The top (18) bimetal should be approximately

1/32-inch off the lever and the bottom (19) bimetal should

be in contact with the lever.

2. With a .048-inch six spline wrench, turn the calibration

screw clockwise if the controlled pressure is above

8 psig and counterclockwise if the controlled pressure is

below 8 psig. Adjust the screw until the pressure is ± 1

psi.

3. Manually switch the thermostat several times by

removing and reinserting the AL-80 or screwdriver and

observing the branch line pressure. If it varies beyond the

limits, repeat the calibration.

4. Remove the test gauge.

5. Turn the test point screw clockwise to tighten.

6. Replace cover.

MAINTENANCE

The pneumatic thermostat requires no routine

maintenance.

REPAIR

Field repair of pneumatic thermostats is not

recommended. However, if the thermostat output

pressure is 0 and it cannot be corrected by calibration,

the restriction should be checked. Hold the restriction

plate up to the light and check the .0075 hole. If the hole

is blocked, the restriction plate must be replaced. the

filter should be replaced at the same time. If the hole is

not blocked, then the thermostat should be replaced.