Carrier 50PEC09-18 Install Supply and Return Piping, Rnet Wiring Specifications, A50-8443

Table 6 — Rnet Wiring Specifications

RNET WIRING SPECIFICATIONS

	Description	4 conductor, unshielded, CMP,
		plenum rated cable
	Conductor	18 AWG
	Maximum Length	500 ft
Recommended Coloring		Jacket: white
		Wiring: black, white, green, red
	UL Temperature	32 to 167 F
	Voltage	300-vac, power limited
	Listing	UL: NEC CL2P, or better
	LEGEND
AWG — American Wire Gage
CMP	— Communications Plenum Cable
NEC	— National Electrical Code
UL	— Underwriters Laboratories

To wire the SPT sensor to the controller:

1.Partially cut , then bend and pull off the outer jacket of the Rnet cable(s), being careful not to nick the inner insulation.

2.Strip about 1/4 in. of the inner insulation from each wire. See Fig. 34.

OUTER JACKET

a50-8443

.25 IN. INNER INSULATION

Fig. 34 — Rnet Cable Wire

3.Wire each terminal on the sensor to the same terminal on the controller. See Fig. 25-29. Table 7 shows the recom- mended Rnet wiring scheme.

Table 7 — Rnet Wiring

WIRE	TERMINAL
Red	+12-v
Black	.Rnet–
White	Rnet+
Green	Gnd

NOTE: The wire should be connected to the terminal shown.

Wiring a Supply Air Temperature (SAT) Sensor — The SAT sensor is required for reheat applications.

If the cable used to wire the SAT sensor to the controller will be less than 100 ft, an unshielded 22 AWG (American Wire Gage) cable should be used. If the cable will be greater than 100 ft, a shield 22 AWG cable should be used. The cable should have a maximum length of 500 ft.

To wire the SAT sensor to the controller:

1.Wire the sensor to the controller. See Fig. 25-29.

2.Verify that the Enable SAT jumper is on.

3.Verify that the Enable SAT and Remote jumper is in the left position.

Wiring an Indoor Air Quality (IAQ) Sensor — An IAQ sensor monitors CO2 levels. The WSHP Open controller uses this information to adjust the outside-air dampers to provide proper ventilation. An IAQ sensor can be wall-mounted or mounted in a return air duct. (Duct installation requires an aspi- rator box assembly.)

The sensor has a range of 0 to 2000 ppm and a linear 4 to

20 mA output. This is converted to 1 to 5 vdc by a 250-ohm, 1/4 watt, 2% tolerance resistor connected across the zone con- troller’s IAQ input terminals.

NOTE: Do not use a relative humidity sensor and CO2 sensor on the same zone controller if both sensors are powered off the board. If sensors are externally powered, both sensors may be used on the same zone controller.

If the cable used to wire the IAQ sensor to the controller will be less than 100 ft, an unshielded 22 AWG (American Wire Gage) cable should be used. If the cable will be greater than 100 ft, a shield 22 AWG cable should be used. The cable should have a maximum length of 500 ft.

To wire the IAQ sensor to the controller:

1.Wire the sensor to the controller. See Fig. 25-29.

2.Install a field-supplied 250-ohm, 1/4 watt, 2% tolerance resistor across the controller’s RH/IAQ and Gnd terminals.

3.Verify the the RH/IAQ jumper is set to 0 to 5-vdc.

Wiring a Relative Humidity (RH) Sensor — The RH sensor is used for zone humidity control (dehumidification) if the WSHP unit has a dehumidification device. If not, the sensor only monitors humidity.

NOTE: Do not use a relative humidity sensor and CO2 sensor on the same zone controller if both sensors are powered off the board. If sensors are externally powered, both sensors may be used on the same zone controller.

If the cable used to wire the RH sensor to the controller will be less than 100 ft, an unshielded 22 AWG (American Wire Gage) cable should be used. If the cable will be greater than 100 ft, a shield 22 AWG cable should be used. The cable should have a maximum length of 500 ft.

To wire the RH sensor to the controller:

1.Strip the outer jacket from the cable for at least 4 inches.

2.Strip 1/4 in. of insulation from each wire.

3.Wire the sensor to the controller.

Step 6 — Install Supply and Return Piping

CAUTION

To ensure proper functioning of unit and system, be sure to connect entering water to upper pipe on right-hand units. On left-hand units, connect entering water to lower pipe. Failure to do so could result in equipment damage.

SUPPLY AND RETURN HOSES — Optional pressure-rated hose assemblies are available for use with units. Use the fol- lowing guidelines when installing supply and return hose assemblies.

1.Install supply and return hoses fitted with swivel-joint fittings at one end to prevent the hose from twisting.

2.Use male adapters to secure the hose assembly to the unit and the riser.

3.Do not allow the hose to twist during installation. Twist- ing may damage the hose wall or the rubber compound.

4.Use pipe joint compound sparingly on the fitting adapt- ers’ male pipe threads.

5.Prevent sealant from reaching the joint’s flared surfaces.

6.Do not use pipe joint compound when Teflon* thread tape is pre-applied to hose assemblies or when flared-end connections are used.

7.Maximum torque that may be applied to brass fittings is 30 ft-lb. When a torque wrench is not used, tighten brass fittings finger-tight plus one quarter turn.

8.Tighten steel fittings as necessary.

9.Use shut-off/balancing valves, flow indicators, and drain tees in the supply runout and return at each floor to aid in loop balancing and servicing.

SUPPLY AND RETURN PIPING — System piping MUST comply with all applicable codes.

1.Install a drain valve at the base of each supply and return riser to enable system flushing at start-up and during rou- tine servicing.

*Teflon is a trademark of E. I. du Pont de Nemours and Company.

32