A. caution, A. warning – Carrier 48XL User Manual
Page 22
Attention! The text in this document has been recognized automatically. To view the original document, you can use the "Original mode".

INFINITY CONTROLLED LOW AMBIENT COOLING
NOTE:
When this unit is operating below 33°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 temperature plus 3°F(f.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 temperature plus f°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 23°F (f3,8°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 f 0 minutes with the compressor running. If LPS closes within fO 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. SEOUENCE OF OPERATION-GAS HEAT NOTE: Infinity control must be grounded for proper operation or NOTE: If a power interruption occurs during a call for heat, the control will start a 90-second blower only ON period two seconds GAS HEAT MODE AND ADJUSTMENTS When the UI calls for gas heat, the Infinity furnace board performs 1, Inducer Pre-purge Period: When the inducer motor comes up on high speed, the pressure switch closes, and the 2, Trial-For-Ignition Sequence: The spark igniter will spark for 3 seconds. The main gas valve relay contact closes to 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 If the burner flame is not proved within 2 seconds, the control will If flame is proved when there should be no flame present, control 4, Blower-On Delay: If the burner flame is proven, approximately 37 seconds after the gas valve is opened the Simultaneously, the humidifier terminal HUM and electronic air NOTE: EAC-2 terminal is common with L2 and will have 113VAC-to-ground when unit is powered. 3, Blower-Off Delay: When the call for gas heat is satisfied, the gas valve is de-energized, stopping the flow of gas to CHECK GAS INPUT (NATURAL GAS) A. CAUTION UNIT DAMAGE HAZARD Failure to follow this caution may result in component Do not redrill an orifice. Improper drilling (burrs, out-of-round holes, etc.) can cause excessive burner noise A. WARNING EIRE HAZARD Failure to follow this warning could result in personal DO NOT bottom out gas valve regulator adjusting screws. 22
See UI Installation Instructions for more details,
control will lock out,
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,
a self-check, verifies the pressure switch is open, and starts the
inducer on high speed,
Infinity ignition control on the furnace board begins a 13
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 13 second pre-purge period.
energize the gas valve on low stage. After 3 seconds, the
igniter is de-energized and a 2-second flame-proving
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.
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 SECl or
SEC2 to the furnace board.
will lock out of Gas-Heating mode and operate the inducer motor
until flame is no longer proved,
Indoor Blower is turned on to the appropriate speed for the
gas heating stage.
cleaner terminal EAC-1 are energized throughout the heating
cycle,
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-1
will remain energized for 90, 120, 130, or 180 seconds
(depending on selection of blower-off delay selected in the
UI). The factory-set default is 120-second blower-OFF
delay.
damage.
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.
injury, death and/or property damage,
This can result in unregulated manifold pressure and result
in excess overfire and heat exchanger failures.