P74JA Differential Pressure ControllerDetailed product description：

Product Introduction
The P74JA differential pressure controller combines two highly sensitive pressure elements, which once changed, cause the switch mechanism to operate to control equipment such as motor-driven valves. The switch mechanism provides SPDT non fast acting (floating) action, so the shared movable contacts will contact one of the two fixed contacts or stay between them (non-contact).

Specifications
Single blade double switch, fully enclosed Penn switch.
The 1/4 "horn pressure expansion tube is connected to the tactile element for easy on-site installation.
The direct reading ruler can quickly determine the set point.
The pressure difference setting can be changed without moving the outer cover.

Application
The P74JA differential pressure controller is commonly used in water systems to control the pressure difference between the supply and return pipes. After the SPDT floating action of the controller is connected to the contact, the motor driver operates the valve. A typical application is to install valves in the bypass pipeline of the system water pump accessories. When the system pressure difference increases and exceeds the set value of the controller, the valve will further open, and more water will flow through the bypass valve, thereby reducing the system pressure difference. The decrease in pressure difference causes the valve to start closing and the system pressure difference to increase.
P74JA is also suitable for applications with pressure differentials in other gases or liquids.
All P74 series controllers are designed for operational control purposes only.
If there is a possibility of personnel injury or property damage due to operational loss of control, the installer is responsible for increasing facilities (safety, restriction control), providing protection, or adding systems
(Alarm, monitoring system), issuing an alarm in case of loss of control.
Device installation
Install the controller at any position on a flat surface or control screen. Tighten the holes on the back of the box with two screws or bolts, or use the No271-51 universal mounting bracket for installation. The controller should be installed so that the joint of the bellows is above the liquid level of the equipment being used. This can reduce the possibility of external problems accumulating inside the corrugated tube.

General Instructions
Confirm that the controller is not installed on an instrument that would cause excessive electrical specifications. For the maximum electrical specifications and contact actions of the controller, please refer to the label attached on the inside of the controller casing.
Before connecting the pressure controller, all pipelines should be cleaned and vented first.
Avoid sharp bending or twisting of copper pipes.
Reserve a longer connecting copper tube to curl and securely install that part to avoid vibration, leaving some slack in the connecting copper tube to prevent "string" vibration when it is too tight
Causing the breakage of the connecting copper pipe. Prevent friction or impact between the connecting copper tube and the surrounding surface to prevent damage to the connecting copper tube.

Electrical wiring
Attention: Before wiring, the power should be cut off to prevent possible electric shock or damage to the equipment.
All wiring must use copper wires and comply with local regulations and national electrical codes. All motor driver wiring uses AWG18 or thicker wires. Lines over 500 feet in length should use AWG14 wire. All cable joints should be in junction boxes, using approved non welded joints, or welded and wrapped at the connection points. Note: Assemble with terminal screws (8-32 × 1/4 "connector). Using alternative screws for connection may cause issues with proper connection.

performance

product		Differential pressure controller P74JA-3
Scale range		8 to 60 PSI (55 to 414 KPa)
Operating pressure difference		2PSI(14KPa)， Fixed
Maximum overpressure of corrugated pipe		180PSIG(1241KPa)
Maximum allowable pressure difference of corrugated pipe		120PSI(830KPa)
Electrical specifications		1 ampere, 24V AC, 50/60Hz
Contact element		SPDT fully enclosed floating PENN switch
material	box	1.6mm， cold-rolled steel
	Shell	0.6mm， cold-rolled steel
Coating		Grey baked paint
Install		Installed on a flat surface and using a universal mounting bracket
Wire connection		Use color coded screws or wiring terminals
weight		1.1Kg
runtime Ambient temperature	Minimum	-1℃
	highest	60℃

Attention: This controller should not be used to control relays or starters to prevent short circuits or oscillations.
Debugging
Insert the screwdriver into the gap of the turntable and rotate the turntable until the dial pointer is aligned with the desired position. Rotate the dial to the left to increase the differential setting value, or to the right to decrease the differential setting value.
To change the set point, adjust the dial to the left or right from the front or side view of the controller (see Figure 2).
Verification process
Before leaving the device, the complete operation process should be observed at least three times to ensure that the functions of all components are correct and error free.



Note: When the pressure difference decreases, the motor rotates clockwise to turn the valve to the closed position.
When the pressure difference increases, the motor rotates counterclockwise to turn the valve to the open position.