Carrier 42 SERIES specifications Control Selection Guide

CONTROL SELECTION GUIDE

Use this guide to make sure that all necessary components are provided for and that the components are compatible with the required control system.

NOTE: When thermostatic fan control is selected or when unit outside air dampers are used, unit-mounted thermostats are not recommended as their use will result in poor room temperature sensing.

				CHANGEOVER		FAN
	SYSTEM	DESCRIPTION	THERMOSTAT	ON	VALVE		NOTES
						SWITCH (SW)
				SUPPLY PIPE
	Fan	Fan manually cycled	None	None	None	Standard	Not recommended
	Control					3-Speed SW	for high humidity
	(2-Pipe)						application
		Thermostat cycles fan on-off	Wall mounted	None	None	Thermostat has
		from speed set with	includes heat-cool			integral
		fan switch.	switch.			3-Speed SW
		Thermostat cycles fan on-off	Wall mounted.	Yes	None	Standard	Unit mounted
		from fan speed set	Heating/cooling			3-Speed SW	thermostats provide
		with switch. Mode	Thermostat				very poor room
-COOLING*		automatically switched					temperature control
		by changeover
		sensing water temp.
		Thermostat cycles fan from	Wall or unit	Yes	None	No Standard	Best fan cycle
		high to low on cooling	mounted			3-Speed Switch,	control for
		and low to off on heating.				ON-OFF toggle SW	high humidity
HEATING
						only	applications
	Two-	Thermostat cycles valve	Wall mounted	None	Motorized (N.C.)	Thermostat	Valve packages
	position	open or closed.	includes heat-cool		3-way or 2-way,	has integral	with belled end(s)
	electric		switch.		no bypass required.	3-Speed SW	for ®eld soldering
PIPE	valves						to coil.
		Thermostat cycles valve	Wall or unit	Yes	Motorized (N.C.)	Standard
	(2-pipe)
		open or closed.	mounted.		3-way or 2-way	3-Speed SW.
2-		Mode automatically	Heating/cooling			Others have
		switched by changeover	Thermostat			thermostats with
		sensing water temp.				integral 3-Speed SW
	Pneumatic	Thermostat modulates	By others.	By others.	2- and 3-way	Standard	Factory assembled
	modulating	pneumatic control valve.			furnished by others.	3-Speed SW	in valve package
	valves				Can be equipped		w/¯are nuts.
	(2-pipe)				with factory		Valve packages
					assembled		with belled end(s)
					valve package.		for ®eld soldering
							to coil.
	Two-	Thermostat cycles valve	Wall or unit	Yes.	Motorized	Standard	Valve packages
	position	open or closed. 2° F after	mounted. Sequenced	Two Required.	3-way or 2-way	3-Speed SW	with belled end(s)
	electric	valve closes, thermostat	heating and cooling.			Others have	for ®eld soldering
	valve with	activates electric heater.				thermostats with	to coil.
	Auxiliary	Heater can't turn on				integral 3-Speed SW
	Electric	if hot water is in coil.
	Heat
		Thermostat cycles valve	Wall mounted	None	Motorized	Thermostat	Valve packages
	(2-pipe)
		open or closed. Manual	includes heat-cool		3-way or 2-way,	has integral	with belled end(s)
		changeover switch	switch.		no bypass required	3-Speed SW	for ®eld soldering
		changes thermostat to					to coil.
HEAT		heat to activate electric
		heater.
	Two-	Thermostat cycles valve	Wall mounted	None	Motorized (N.C.)	Thermostat	Valve packages
ELECTRIC	position	open or closed.	includes heat-cool		3-way or 2-way,	has integral	with belled end(s)
	electric	Manual changeover switch	switch.		no bypass required	3-Speed SW	for ®eld soldering
	valve with	changes thermostat to heat					to coil.
	total	to activate electric heater.
	electric
		Thermostat cycles valve	Wall or unit	None	Motorized (N.C.)	Standard
	heat	open or closed.	mounted.		3-way or 2-way,	3-Speed SW
	(2-pipe)
		2° F after valve closes,	Sequenced heating		no bypass required
		thermostat activates	and cooling
		electric heater.
	Pneumatic	Thermostat modulates	By others.	By others.	2- and 3-way	Standard	Factory assembled
	modulating	pneumatic control valve.			furnished by others.	3-Speed SW	in valve package
	valves	After changeover,			Can be equipped		w/¯are nuts.
	(2-pipe)	thermostat			with factory		Valve packages
		activates electric heater.			assembled		with belled end(s)
					valve package.		for ®eld soldering
							to coil.
	Two-	Thermostat cycles	Wall mounted	None	Motorized (N.C.)	Thermostat	Valve packages
	position	cooling and heating	includes subbase		3-way or 2-way	has integral	with belled end(s)
	electric	valves open or closed.	with heat-cool		(requires 2 valves)	3-Speed SW	for ®eld soldering
	valves		switch.				to coil.
	(4-pipe)
		Thermostat cycles cooling	Wall or unit	None	Motorized (N.C.)	Standard
		valve open or closed. 2° F	mounted.		3-way or 2-way	3-Speed SW.
PIPE		after valve closes,	Sequenced heating		(requires 2 valves)	Others have
		thermostat cycles	and cooling.			thermostats
		heating valve open or closed.				with integral
4-						3-Speed SW
	Pneumatic	Thermostat modulates	By others.	By others.	2- or 3-way	Standard	Factory assembled
	modulating	cooling valve.			furnished by others.	3-Speed SW	in valve package
	valves	After changeover,			Can be equipped		w/¯are nuts.
	(4-pipe)	thermostat modulates			with factory		Valve packages
		heating valve.			assembled		include unions for
					valve package.		for ®eld assembly
							to coil.

*If system is HEATING-ONLY or COOLING-ONLY, no changeover or bypass is required.

NOTE: Unit-mounted thermostats are not recommended with either fan-cycle control or applications with outside air dampers.

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