Aiko CTH3-150, CTH3-80, CTH3-200 Cable Termination, Power Requirements, Remote Analog Signal

CTH3-SERIES INSTALLATION, OPERATION AND SERVICE MANUAL

10.4.7 Cable Termination

Table lists wiring types, sizes and distances for modulating thermostat with LonWorks® communication (P/N 90425104), modulating thermostat without communication (P/N 90425105) and BACnet® programmable thermostat

(P/N 90425109)

Table 4: Cable Requirements

Wire Function	Recommended Wire Size		Specification or	Distance (Maximum)
		(Minimum)	Requirement
Digital Outputs	18	AWG (0.75 sq mm)	Standard thermostat wire	1000 ft (304 m)
Modulating Outputs	18	AWG (0.75 sq mm)	1 pair	500 ft (152 m)
Outdoor Air Temperature Sensor	18	AWG (0.75 sq mm)	1 pair	500 ft (152 m)
Remote Sensor	18 to 22 AWG		Twisted pair wire	1000 ft (304 m)
	(0.75 to 0.34 sq mm)
Power Wiring	18 to 14 AWG		NEC Class II 140ºF (60°C )	Limited by line-loss effects on power
	( 0.75to 2.0 sq mm)			consumption.
LonWorks® (P/N 90424104 only)	18	AWG	1 pair	Refer to E-bus Wiring Guide 74-2865
	(0.75 sq mm) nonshielded			for maximum length and generic cable
				specifications.
MS/TP (P/N 90425109)	18	AWG (0.75 sq mm) Shield	Belden cable #82760 or equivalent	Refer to Thermostat Installation Guide

Power Requirements

Modulating thermostats require 24 volts, AC power.

10.4.8 Remote Analog Signal

Remote Analog Signal 0-10 Vdc or 4-20mA output from external controller or Building Management System (BMS) directly dictates heater(s) firing rate. An algorithm must be programmed into the BMS or external controller to receive zone air temperature signals from its own temperature sensors and then deliver an output signal to the heater(s) for the desired firing rate.

For 0-10Vdc control of the heater(s) firing rate, the following control conditions apply:

ON/OFF relay at the external controller or BMS must be wired to R and W terminals on the heater control board to turn the heater ON and OFF.

Minimum rated input at 1% of signal (0-1Vdc).

Full rated input at 90% of signal (9Vdc).

Input varies linearly between 1Vdc and 9Vdc.

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