Middleby Marshall PS220, PS570, PS360, PS200 Appendix - Instructions for Service Kits 33984 and

SECTION 3 - SERVICING COMPONENTS

Appendix - Instructions for Service Kits 33984 and 33985 -

Oven Thermocouple Kit, 11/01

PS200 Series - before 2/96, serial numbers before ASH-0001

Thermocouples on these ovens are located inside the ma- chinery compartment. They are secured in place by a set screw in the mounting tube, inside the plenum chamber.

This Kit eliminates the set screw. The new thermocouple is held in place by the head of the screw that is already used to attach the mounting tube.

NOTE FOR HIGH LIMIT THERMOCOUPLES:

CE ovens and PS200VL models have two thermocouples, one mounted above the other. In these ovens, the upper thermocouple senses the oven temperature and is con- nected to the temperature controller. The lower thermo- couple is connected to the high limit control module. Ei- ther thermocouple can be replaced using this Kit.

1.	Remove the lower end plug from the control end of the
	oven. Then, remove 1 or 2 lower air fingers as neces-
	sary to access the thermocouple mounting tube.
2.	Refer to Figure 1. REMOVE AND DISCARD the set
	screw and pull the thermocouple out of the mounting
	tube. Disconnect the thermocouple wiring from the tem-
	perature controller or high limit module, as appropriate.
3.	Remove AND RETAIN the #10-16 screw that fastens
	the flange of the thermocouple mounting tube to the
	plenum wall. Leave the mounting tube in place.
4.	Install the new thermocouple so that its flange fits firmly
	against the mounting tube flange.

Figure 1

Thermocouple Installation - PS200 Series

Thermocouple	Mounting		Mounting
			tube
	tube		screw
Set screw			Thermocouple
	Oven	Tube	flange
(not used with new	wall
		flange
thermocouple)

CORRECT	INCORRECT
Thermocouple flange sits firmly on	Thermocouple flange sits on top of
mounting tube flange; tube	screw head, leaving a gap as
mounting screw holds thermo-	shown.
couple in place.

Figure 2

Thermocouple Wiring - PS200 Series

5.	Replace the #10-16 screw that you removed in Step 3.
	Check that the head of the screw holds the thermo-
	couple flange securely in place, as shown in Figure 1.
6.	Route the thermocouple leads away from the ignition
	cable. Connect the leads as shown in Figure 2.

PS200 Series - 2/96 or later, serial numbers after ASH-0001

Thermocouples on these ovens are located in the same position as the earlier PS200 models described above. However, these ovens feature a flanged thermocouple iden- tical to the new thermocouple provided in this Kit.

The thermocouple SHOULD be held in place by the screw that attaches the thermocouple mounting tube, as per the replacement procedure above. For these ovens, simply disconnect the thermocouple wiring from the temperature controller and follow Steps 3-6 of the procedure shown above to remove and replace the thermocouple.

On some of these ovens, the thermocouple flange rests ON TOP of the retaining screw for the mounting tube, as shown in the “INCORRECT” inset of Figure 1. These ther- mocouples are held in place by the set screw on the mount- ing tube, inside the plenum chamber. For these ovens, you should remove and replace the thermocouple by following

Steps 1-6 of the preceding section.

2

White

Red

Shielded

ground lead

Analog

Temperature

Controller

Red White

Shielded

ground lead

Digital

Temperature

Controller

Shielded

White Red ground lead

High Limit

Control

Module

57