Carrier 42 SERIES specifications STANDARD WIRING PACKAGES cont

STANDARD WIRING PACKAGES (cont)

Thermostatic 2-Pipe Auxiliary Electric Heat with Valve Control Ð This system, also called Twi- light or Intermediate Season electric heat, goes a long way towards solving the spring and fall control problems of 2-pipe systems.

You can run chilled water late into the fall, turn it on early in the spring and still have heat available to all units when- ever required.

In winter the system is switched over to hot water. Two changeover devices are required for this. One device switches the action of the thermostat and the other locks out the elec- tric heat when hot water is in the coil.

With this system, the fan runs continuously unless manu- ally switched to OFF position. Fan must be on before ther- mostat can send signal to open chilled water valve or turn on electric heater.

Two control methods are available:

1.Use the standard automatic changeover thermostat with a dead band between heating and cooling, or Ð

2.Use a manual changeover thermostat. With this method only one changeover is required.

Be sure to include a 2-way or 3-way electric valve with this system.

NOTE: Wiring diagrams are for 120-v power supply. If other voltages for heaters or controls are speci®ed,wiring may dif- fer from that shown.

For control package descriptions, see control components sections entitled Remote-Mounted Controls and Unit- Mounted Controls.

UNIT	LOCATION	WIRING PACKAGE*		ELECTRIC
TYPE		Automatic System	Manual System	VALVE
Vertical	Unit	24-Q	Available on Special Order.
	Mounted			Any 2- or 3-way,
Vertical		22-J, 22-K,		2-position valve
or	Wall Mounted		23-15, 23-16	Package.
		23-09, 23-10
Horizontal

*Packages on current price pages.

NOTES:

1.Motors are thermally protected.

2.Use copper conductors only.

3.See unit nameplate for power supply. Provide disconnect means and overload protection as required.

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