Installation & Service Manual
5Electrical connections (continued)
Outdoor Air Temperature Sensor
The outside air temperature sensor will only be used for boiler systems. The outside air sensor is optional. This sensor allows you to tie boiler operation to the outdoor air temperature. As outside temperatures drop, the control will increase the temperature setting of the boiler. As outdoor temperatures rise, the control will decrease the temperature to the selected set point of the boiler. You can set the control to shut the boiler off when a desired outdoor air temperature level is reached.
You must purchase the sensor from the appliance manufacturer. The sensor comes with a housing that helps protect the sensor from the elements. Mount the air sensor housing outdoors, under the eve of the roof. Make sure the housing is out of direct sunlight. This will ensure that the sensor will accurately read the true outdoor temperature. Connect the outdoor air temperature sensor to the terminal block on the outdoor air reset board. For more information on wiring the sensor, see Wiring of Remote Sensors, this page.
Wiring of Remote Sensors
To wire remote sensors, follow the guidelines below. Take care to correctly wire sensors to the unit. Erratic temperature readings can be caused by poor wiring practices. Twist the wires between the unit and the remote sensor. Turn wires at least three or four turns per linear foot of wiring. This provides protection against some types of electrical interferences.
1.Do not route temperature sensor wiring with building power wiring.
2.Do not locate temperature sensor wiring next to control contactors.
3.Do not locate temperature sensor wiring near electric motors.
4.Do not locate temperature sensor wiring near welding equipment.
5.Make sure good mechanical connections are made to the sensor, any interconnecting wiring and the controller.
6.Do not mount sensor with leadwire end pointing up in an area where condensation can occur.
7.Use shielded wiring to connect the sensor to the control when the possibility of an electrically noisy environment exists. Shielded cable is recommended on all cable runs of more than 25 feet in length.
NOTICE | Ground the cable shield at the connection | |
to the boiler temperature control only. Do | ||
| ||
| ||
| not ground the shielded cable at the sensor | |
| end. |
To maintain temperature accuracy, sensor wires should be 18 AWG two conductor (18/2). Use shielded wire if required.
Installation of Remote Sensors
1.Turn OFF the main electrical power and the main manual gas shutoff to the appliance.
2.Remove the side access panel from the appliance to gain access to the thermostat.
3.Locate the sensor in the kit. Determine the location of the remote sensor and measure the amount of wire needed to connect the sensor to the thermostat. See Wiring of the Remote Sensors for guidelines.
4.Use twisted pair wire, minimum 18 gauge or larger. See Table 5A, page 34 regarding distance versus wire gauge. Ensure all wire insulation is trimmed to reveal at least 3/8" of exposed wire.
5.Connect the measured wire to the sensor wire using wire caps (see FIG.
6.Turn on the electrical power and the main manual gas shutoff to the appliance.
7.Replace the side access panel.
8.Fire the appliance and resume operation.
ACCESS HOLE 
CONNECT THE MEASURED 
WIRE TO THE SENSOR WIRE
Figure 5-4_Installation of Remote Sensors
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