Carrier 48XL Infinity Controlled LOW Ambient Cooling, Dehumidification Mode, Hum, Eac-I, EAC-2

INFINITY CONTROLLED LOW AMBIENT COOLING

NOTE: When this unit is operating below 55°F (13°C) outdoor

temperature, provisions must be made for low ambient operation.

This unit is capable of low ambient cooling down to 0°F

(-18°C).ONLY when using the Infinity control. A low ambient kit

is not required, and the outdoor fan motor does not need to be

replaced for Infinity controlled low ambient operation. Low

ambient cooling must be enabled in the UI set-up. Fan may not

begin to cycle until about 40°F (4°C).OAT. Fan will cycle based

on coil and outdoor air temperature. Infinity controlled low ambient mode operates as follows:

•In high stage, fan is off when outdoor coil temp is <outdoor air

temperature plus 3 ° F (1.7 ° C) or outdoor fan has been ON for 30

minutes. (Fan is turned off to allow refrigerant system to stabilize.)

•In low stage, fan is off when outdoor coil temp is <outdoor air

temperature plus 1 °F (.6°C) or outdoor fan has been ON for 30

minutes. (Fan is turned off to allow refrigerant system to stabilize.)

•In high stage and low stage, fan is on when outdoor coil temp >

outdoor air temperature plus 25 °F (13.8 ° C) or outdoor coil temp > 80°F (27°C) or if outdoor fan has been OFF for 30 minutes.

(Fan is turned on to allow refrigerant system to stabilize.)

•Low-pressure switch is ignored for first 3 minutes during low ambient start up. After 3 minutes, if LPS trips, then outdoor fan

motor is turned off for 10 minutes with the compressor running. If

LPS closes within 10 minutes then cooling continues with the

outdoor fan cycling per the coil temperature routine listed above for the remainder of the cooling cycle. If the LPS does not close within 10 minutes, then the normal LPS trip response (shut down

cooling operation and generate LPS trip error) will occur.

DEHUMIDIFICATION MODE

This Infinity system can be used to dehumidify the living space.

See UI Installation Instructions for more details.

SEQUENCE OF OPERATION-GAS HEAT

NOTE: Infinity control must be grounded for proper operation or control will lock out.

NOTE: If a power interruption occurs during a call for heat, the

control will start a 90-second blower only ON period two seconds after power is restored, if the UI is still calling for gas heating. The

amber LED light will flash code 12 during the 90-second period,

after which the LED will be ON continuously, as long as no faults

are detected. After the 90-second period, the unit will respond to the UI normally.

GAS HEAT MODE AND ADJUSTMENTS

When the UI calls for gas heat, the Infinity furnace board performs

a self-check, verifies the pressure switch is open, and starts the inducer on high speed.

1. Inducer Pre-purge Period: When the inducer motor comes

up on high speed, the pressure switch closes, and the

Infinity ignition control on the furnace board begins a 15

second pre-purge period. If the pressure switch fails to

remain closed, the inducer will remain running. After the

pressure switch re-closes, the Infinity ignition control will

begin a 15 second pre-purge period.

2. Trial-For-Ignition Sequence: The spark igniter will spark

for 3 seconds. The main gas valve relay contact closes to energize the gas valve on low stage. After 5 seconds, the

igniter is de-energized and a 2-second flame-proving

period begins.	NOTE:	The unit	always	lights on	high
speed inducer and low stage gas valve operation.
3. Flame-Proving:	When	the burner	flame	is proved	at the
flame-proving	sensor,	the furnace	control	determines	what

heating stage to run based on feedback from the UI. If the UI is asking for low stage gas heat, the ignition control will

change the inducer speed to low speed and keep the gas valve energized on low stage. If the UI is asking for high stage gas heat, the ignition control will maintain running the

inducer on high speed and energize the gas valve's high stage relay to increase gas flow.

If the burner flame is not proved within 2 seconds, the control will

close the	gas valve	and	repeat		the	ignition sequence up to 3 more
Trials-For-Ignition		before		going		to	Ignition-Lockout.		Lockout
will reset	automatically		after	3	hours,		by	momentarily	interrupting
230 VAC	power,	or by	interrupting				24	VAC power	at SEC1 or
SEC2 to the furnace board.

If flame is proved when there should be no flame present, control

will lock out of Gas-Heating					mode and operate the inducer motor
until flame is no longer proved.
4.	Blower-On		Delay:			If the	burner	flame	is	proven,
	approximately		37	seconds after			the gas	valve is opened			the
	Indoor Blower		is	turned on to the appropriate					speed	for	the
	gas heating	stage.
Simultaneously,		the	humidifier			terminal	HUM	and	electronic		air
cleaner	terminal	EAC-I			are	energized	throughout		the	heating
cycle.
NOTE:	EAC-2		terminal		is	common	with L2 and will have
ll5VAC-to-ground			when		unit	is powered.

5.Blower-Off Delay: When the call for gas heat is satisfied,

the gas valve is de-energized, stopping the flow of gas to

the burners, and de-energizing the HUM terminal. The

inducer motor will remain on for a 4-second post-purge

period. The indoor blower and air cleaner terminal EAC-I

will remain energized for 90, 120, 150, or 180 seconds

(depending on selection of blower-off delay selected in the

UI). The factory-set default is 120-second blower-OFF delay.

CHECK GAS INPUT (NATURAL GAS)

[]NIT DAMAGE HAZARD

Failure to follow this caution may result in component

damage.

Do not redrill an orifice. Improper drilling (burrs,

out-of-round holes, etc.) can cause excessive burner noise

and misdirection of burner flame. If orifice hole appears

damaged or it is suspected to have been redrilled, check

orifice hole with a numbered drill bit of correct size.

FIRE HAZARD

Failure to follow this warning could result in personal iniury, death and/or property damage.

DO NOT bottom out gas valve regulator adjusting screws.

This can result in unregulated manifold pressure and result

in excess overfire and heat exchanger failures.

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