Emerson E2 Product Temperature Probes, Humidity Sensors and Humidistats, Indoor RH Sensor

outside and inside temperature to monitor supply and return air temperature. When used in this application, the sensors are supplied without enclosure covers. The sensors should be mounted directly in the air stream of the supply or return air duct. The sensors are not supplied with any mounting hardware for this application.

3.5.6Refrigeration System Tem- perature Probes and Sensors

3.5.6.1Location

Retail Solutions supplies several temperature monitor- ing devices including bullet sensors, pipe mount sensors, immersion probes, insertion probes, and sensors for high temperature applications. Each of these sensors is gener- ally installed on the system by the equipment manufac- turer. If a device must be added to the system, refer to the information supplied with the device and consult the refrigeration equipment manufacturer. Table 3-1lists some typical sensor applications and the sensor or probe most suited for that purpose.

Application	Sensor Type
Condenser Outlet (Drop Leg)	High Temperature Bullet
Liquid (Manifold)	Pipe Mount
Suction Temperature	Pipe Mount
Discharge Air	Bullet
Ambient Temperature (Outside)	Bullet
Condenser Sump	Insertion Probe
Defrost Termination	Bullet

Table 3-1- Sensor Application and Type

3.5.6.2Mounting Bullet and Pipe Mount

Sensors

Bullet or pipe mount sensors mounted on refrigerant lines should be secured with a Panduit low temperature cable tie, number PLT2S-M120, or equivalent. For pipe mount sensors, the curved surface should be placed against the pipe and the tie should be positioned in the groove on the top surface of the sensor. A second tie should be used to secure the lead to the pipe for additional support.

Sensors located on refrigerant lines should be insulated to eliminate the influence of the surrounding air. A self- adhering insulation that will not absorb moisture is recom- mended to prevent ice logging at the sensor location.

The sensor should be positioned on the side of the line as shown in Figure 3-24.

Figure 3-24- Sensor Orientation

3.5.7Product Temperature

Probes

The product temperature probe is designed to be used alongside food products in a refrigeration case or freezer. The product probe uses a thermistor type temperature sen- sor in a sealed, cylindrical container (approximately 16 oz.). A magnet is contained at the bottom the probe’s enclosure to allow easy attachment to a side or bottom of a refrigeration case.

3.5.8Humidity Sensors and Humidistats

3.5.8.1Indoor RH Sensor

The indoor relative humidity sensor should be mounted in a central location within the zone to be mea- sured, away from doors, windows, vents, heaters, and out- side walls that could affect temperature readings. The sensor should be between four and six feet from the floor. Note that this sensor generates a small amount of heat; therefore, do not mount temperature sensors directly above RH sensors.

Mount RH sensor (P/N 203-5751)as follows:

1.With a flat-head screwdriver, push down the middle tab on the top of the sensor case and pop the lid off to expose the circuit board.

2.Insert the flat-head screwdriver into the two slots on either side of the top of the sensor case and twist to separate the back plate from the case.

3.Remove the knock-outs from the back plate before mounting so wires may be threaded through.

Sensors and Transducers Mounting • 3-9