Heatcraft Refrigeration Products 25000102 Series P100 Pressure Control, Auto Reset Models

Parallel Compressor Systems

Series P100 Pressure Control

The P100 series, manufactured by Johnson Control, Inc., are encapsulated, non adjustable, single-pole single throw, direct mount pressure controls typically used for low or high pressure cutouts. On the Heatcraft manufactured parallel systems, the control is used for High Pressure cutout.

There are two types available. Auto Reset Models and Manual Reset Models.

Figure 13.

Auto Reset Models

When pressurized to the selected actuation pressure setting, the internal snap-acting disc reverses its shape and drives a set of electrical contacts either open or closed. When the pressure drops below the de-actuation pressure setting, the disc snaps back to its preset position thus resetting the electrical contacts.

Manual Reset Models

The snap-acting disc in the manual reset model opens the electrical contacts when actuated by the pressure sensor. Once the disc snaps, the contacts are held open until an external force on the push button closes them. Because of the disc’s link with the pressure sensor, the contacts cannot be reset until the pressure drops to a predetermined level.

The latching mechanism inside the manual reset model is trip free. The electrical contacts will cutout even if the reset button is held fully depressed. The control can only be reset when the pressure returns to a predetermined level.

Liquid Level Switch

S-9400 Level Switch Series

OPTION – Not available on all systems or receivers.

Table 19. Level Switch Table

Cat.	Voltage	Resistive	Contacts
No.		Rating	Liq. Present
S-9420	208/240	.5 Amp	N.C.
	50/60 Hz
Cat.	Wire Color	Replacement	Replacement
			Sight Glass
No.	Code	Module No.
			No.
S-9420	Red & White	2-044-015	3-020-063

Figure 14.

Operation

The S-9400 Series Level Switches manufactured by AC&R Components uses light reflecting from a conical glass prism as a means of detecting the absence of a fluid at the level of the glass cone. When no fluid covers the lower half of the cone, infra-red light from the module reflects from the mirror-like inner surface of the cone back to a light detector signaling the electronic module to switch. When fluid covers the lower half of the glass cone, the light from the module passes into the fluid. This absence of light is detected by the module which switches into the opposite direction. The module provides a

.06/.10 differential distance from the cone point down.

Parallel Compressor Systems Installation & Operations Manual, October 2004 25