Repair

Thermal Limit Sensor

CAUTION

To avoid damaging the capillary tube (GG), which can cause heater malfunction, do not kink or nick the tube.

To avoid shorting out the heater, do not allow the cap- illary tube to contact the block terminal (3A).

1.Follow Pressure Relief Procedure, page 14.

2.Remove housing cover (18).

3.Remove nut (FF) and nut (3B) holding the leads of the thermal limit sensor (15) and remove the sensor. See FIG. 15 or 16, page 19.

4.Apply thin film of thermal lubricant (part no. 110009) to the thermal limit sensor (15) bulb and install a new sensor in the reverse order of disassembly. See Reassembly Notes, below.

Control Knob

1.Follow Pressure Relief Procedure, page 14.

2.Turn knob (33) to setpoint 1.

3.Loosen setscrew (30) in the control knob (33).

4.Remove control knob (33).

5.Remove adjusting knob (12) from the control knob (33), and press fit it onto the new control knob. Check the bushing (29) and replace it if worn.

6.Position new knob (33) so setpoint 1 aligns with mark (JJ) on the housing (12:00 position) and the knob is about 1/16 in. (1 mm) away from the hous- ing. Tighten setscrew (30).

Heater Block

1.Follow Pressure Relief Procedure, page 14.

2.Remove housing cover (18).

3.Hazardous Location Heater only: Remove electrical junction box cover (4).

4.Hazardous Location Heater only: In the junction box (1B), disconnect the main power lead from the ter- minal of the post bushing (9A).

Non-hazardous Location Heater only: Disconnect the main power lead from the primary thermostat

5.Hazardous Location Heater only: In the electrical housing (1A), use a wrench on the flats of the post bushing (9A) to unscrew it from the housing.

6.See the appropriate sections on pages 18-20to remove the primary thermostat and probe (24), the backup thermostat (10), the thermal limit sensor

(15)and the control knob (33).

7.Remove the 6 screws (6) and lockwashers (5) hold- ing the housing to the heater block (3).

8.Reassemble heater with the new block (3) in reverse order of disassembly.

Reassembly Notes

Refer to FIG. 15 or 16 for wiring connections.

Non-hazardous Location Heater only: Make sure gasket (47) is installed and aligned with electrical housing screw holes.

Secure cover (18) with lockwashers (5) and screws (6 or 52); torque screws to 89 in-lb (10 N•m).

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309524N

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Graco 309524N important safety instructions Thermal Limit Sensor, Control Knob, Heater Block