Carrier 48XZ024-030 Assembly Instructions

48XZ
Single-Packaged Gas Heat/Electric Heat Pump
Unit with Puron® (R-410A) Refrigerant
A Guide to Operating and Maintaining Your
Single-Packaged Gas Heat/Electric Heat Pump Unit
NOTE: Read the entire instruction manual before starting the
installation.
SAFETY CONSIDERATIONS
Note to Installer: This manual should be left with the equipment
user.
Installation and servicing of air-conditioning equipment can be
hazardous due to system pressure and electrical components. Only
trained and qualified personnel should install, repair, or service
air-conditioning equipment.
Untrained personnel can perform basic maintenance functions of
cleaning coils and filters. All other operations should be performed
by trained service personnel. When working on air-conditioning
equipment, observe precautions in the literature, tags, and labels
attached to the unit, and other safety precautions that may apply.
Follow all safety codes. Wear safety glasses and work gloves. Use
quenching cloth for unbrazing operations. Have fire extinguisher
available for all brazing operations.
Improper installation, adjustment, alteration, service, mainte-
nance, or use can cause carbon monoxide poisoning, fire, or
an explosion which could result in personal injury or unit
damage. Consult a qualified installer, service agency, or gas
supplier for information or assistance. The qualified installer
or agency must use only factory-authorized kits or accessories
when modifying this product.
Before performing service or maintenance operations on unit,
turn off gas supply to unit. Then turn off unit main power
switch. Electrical shock or explosion could cause serious
injury or death.
Do not store or use gasoline or other flammable vapors and
liquids in the vicinity of this or any other appliance. Failure to
follow this warning could result in fire, serious injury, or
death.
Do not use this unit if any part has been under water.
Immediately call a qualified service technician to inspect the
unit and to replace any part of the control system which has
been under water. Failure to follow this warning could result
in electrical shock, fire, serious injury, or death.
Recognize safety information. This is the safety-alert symbol .
When you see this symbol in instructions or manuals, be alert to
the potential for personal injury.
Understand the signal words DANGER, WARNING, CAUTION,
and NOTE. These words are used with the safety-alert symbol.
DANGER identifies the most serious hazards which will result in
severe personal injury or death. WARNING signifies a hazard
which could result in personal injury or death. CAUTION is used
to identify unsafe practices which would result in minor personal
injury or product and property damage. NOTE is used to highlight
suggestions which will result in enhanced installation, reliability,
or operation.
These instructions cover minimum requirements and conform to
existing national standards and safety codes. In some instances,
these instructions exceed certain local codes and ordinances,
especially those that may not have kept up with changing residen-
tial construction practices. We require these instructions as a
minimum for a safe installation.
UNIT INTRODUCTION
This 48XZ unit is a small packaged gas heat/electric heat pump
system that can utilize both the efficiency of heat pump heating
and the comfort of gas heating. The system will optimize for ideal
heating, depending on several factors. This unit uses Puron®, the
ozone friendly refrigerant for cooling and heat pump heating.
Starting or Shutting Unit Off
1. To start the unit:
a. Turn on the electrical and gas power supply to unit.
b. Select desired temperature on thermostat and set SYSTEM
switch or MODE control to desired mode.
2. To shut unit off:
Fig. 1—Unit 48XZ
C99088
Visit www.carrier.com
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
PC 101 Catalog No. 534–80126 Printed in U.S.A. Form OM48–17 Pg 11–04 Replaces: New
Book 1 4
Tab 1 6

NOTE: If the unit is being shut down because of a malfunction,
call your dealer as soon as possible.
a. Set system SWITCH or MODE control to OFF.
b. Turn off the electrical power, install lock-out tag and shut
off gas supply to unit.
OPERATING YOUR UNIT
The operation of your system is controlled by the indoor tempera-
ture control (for 48XZ, either a Thermidistat™ or dual fuel
thermostat is required). You simply adjust the thermostat and it
maintains the indoor temperature at the level you select. Most
thermostats of heating and cooling systems have 3 controls: a
temperature control selector, a FAN control, and a SYSTEM or
MODE control. Refer to your thermostat owner’s manual for more
information.
To better protect your investment and to eliminate unnecessary
service calls, familiarize yourself with the following facts:
1. During heat pump heating, increasing the thermostat setting
more than 2°F may cause the supplemental gas heat to be
turned on for a short period of time to satisfy the thermostat.
Needless use of the supplementary heat reduces potential
energy savings.
2. Ice or frost tends to form on the coil during winter heating
operation. Your heat pump is designed to automatically melt
the ice. When in this defrost cycle, it is normal for steam or
fog to rise from the outdoor unit. Do not be alarmed!
Step 1—Cooling Mode
With the SYSTEM or MODE control set to COOL, your unit will
run in cooling mode until the indoor temperature is lowered to the
level you have selected. On extremely hot days, your unit will run
for longer periods at a time and have shorter “off” periods than on
moderate days.
Step 2—Heat Pump Heating Mode
With the SYSTEM or MODE control of your indoor thermostat set
to HEAT, your unit will run in heat pump heating mode until room
temperature is raised to the level you have selected. Of course,
your system will run for longer periods to maintain a comfortable
environment on cooler days and nights than on moderate ones.
Step 3—Gas Heat Mode
Your heat pump is your primary heating source. Your system is
also be equipped with a supplemental gas heating source. On cold
days and nights, your system will automatically turn on the
supplemental heat in order to maintain the level of comfort you
have selected.
When your heat pump needs additional heat to keep you comfort-
able, your Carrier electronic thermostat will turn on the supple-
mental gas heat and display the “AUX HT” message.
Step 4—Defrost Mode
When your heat pump is providing heat to your home or office and
the outdoor temperature drops below 45°F, moisture may begin to
freeze on the surface of the coil. If allowed to build up, this ice
would impede airflow across the coil and reduce the amount of
heat absorbed from the outside air. So, to maintain energy-efficient
operation, your heat pump has an automatic defrost mode.
The defrost mode starts at a preset time interval of 30 minutes,
although, it may be reset to 60, 90 or 120 minutes. Defrost will
start at the preset time only if the ice is sufficient to interfere with
normal heating operation.
After the ice is melted from the coil, or after a maximum of 10
minutes in defrost mode, the unit automatically switches back to
normal heating operation.
Do not be alarmed if steam or fog appears at the outdoor unit
during defrost mode. Water vapor from the melting ice may
condense into a mist in the cold outside air.
During certain weather conditions such as heavy snow and
freezing rain it is not uncommon for ice to build up on the unit
grille. This is normal for these weather conditions. Do not attempt
to remove the ice from the unit grille. This condition will not affect
the proper function of the unit and will clear within a few days.
Step 5—Emergency Heat Mode
If you should have problems with the heat pump portion of your
system, this mode allows your supplemental gas heating source to
keep your home or office warm until your heat pump can be
serviced.
MAINTENANCE AND SERVICE
This section discusses maintenance that should be performed on
your system. Most maintenance should be performed by your
dealer. You, as the owner, may wish to handle some minor
maintenance for your new unit.
ROUTINE MAINTENANCE
All routine maintenance should be handled by skilled, experienced
personnel. Your dealer can help you establish a standard proce-
dure.
For your safety, keep the unit area clear and free of combustible
materials, gasoline, and other flammable liquids and vapors.
To assure proper functioning of the unit, flow of condenser air
must not be obstructed from reaching the unit. Clearance from the
top of the unit is 48 in. Clearance of at least 36 in. is required on
sides except the power entry side (42 in. clearance) and the duct
side (12 in. minimum clearance).
MAINTENANCE AND CARE FOR THE EQUIPMENT
OWNER
Before proceeding with those things you might want to maintain
yourself, please carefully consider the following:
1. TURN OFF ALL ELECTRICAL POWER TO YOUR
UNIT AND INSTALL LOCK-OUT TAG BEFORE SER-
VICING OR PERFORMING MAINTENANCE. ELEC-
TRIC SHOCK COULD CAUSE SERIOUS INJURY OR
DEATH.
2. When removing access panels or performing maintenance
functions inside your unit, be aware of sharp sheet metal
parts and screws. Although special care is taken to keep
sharp edges to a minimum, be extremely careful when
handling parts or reaching into the unit.
Air Filters
The air filter(s) should be checked at least every 3 or 4 weeks and
changed or cleaned whenever it becomes dirty. Dirty filters
produce excessive stress on the blower motor and can cause the
motor to overheat and shut down.
This unit must have air filters in place before it can be operated.
These filters can be located in one of at least two places. In many
applications the installer will provide return air filter grilles
mounted on the wall or ceiling of the conditioned structure. In the
instance of filter grilles, the filters can simply be removed from the
grille and replaced.
The other typical application is an accessory filter rack installed
inside the unit itself. The following information is given to assist
in changing filters used in these internal filter racks.
Table 1 indicates the correct filter size for your unit. Refer to Fig.
2 to access filters installed in the accessory filter rack.
2

To replace or inspect filters in accessory filter rack (See Fig. 2):
1. Remove the filter access panel using a 5/16-in. nut driver.
2. Remove the filter(s) by pulling it out of the unit. If the filter(s)
is dirty, clean or replace with a new one.
When installing the new filter(s), note the direction of the airflow
arrows on the filter frame.
If you have difficulty locating your air filter(s) or have questions
concerning proper filter maintenance, contact your dealer for
instructions. When replacing filters, always use the same size and
type of filter that was supplied, originally, by the installer.
Never operate your unit without the filter(s) in place. Failure
to follow this caution will result in damage to the blower
motor and/or compressor. An accumulation of dust and lint on
internal parts of your unit can cause loss of efficiency and , in
some cases, a fire.
Fans and Fan Motors
Periodically, check the condition of fan wheels and housings and
fan-motor shaft bearings. Contact your dealer for the required
annual maintenance.
Indoor and Outdoor Coils
Cleaning of the coils should only be done by qualified service
personnel. Contact your dealer for the required annual mainte-
nance.
Condensate Drain
The drain pan and condensate drain line should be checked and
cleaned at the same time the cooling coils are checked by your
dealer.
Compressor
All compressors are factory-shipped with a normal charge of the
correct type refrigeration grade oil. A compressor should rarely
require additional oil.
Condenser (Outdoor) Fan
Do not poke sticks, screwdrivers, or any other objects into
revolving fan blades. Injury or equipment damage will result.
The fan must be kept free of all obstructions to ensure proper
cooling. Contact your dealer for any required service.
Electrical Controls and Wiring
Electrical controls are difficult to check without proper instrumen-
tations. If there are any discrepancies in the operating cycle,
contact your dealer and request service.
Refrigerant Circuit
The refrigerant circuit is difficult to check for leaks without the
proper equipment. If inadequate cooling is suspected, contact your
local dealer for service.
System under pressure. Relieve pressure and recover all
refrigerant before system repair or final unit disposal to avoid
serious injury or death. Use all service ports and open all
flow-control devices, including solenoid valves. Failure to
follow this warning could result in injury.
Unit Panels
After performing any maintenance or service on the unit, be sure
all panels are fastened securely in place to prevent rain from
entering unit cabinet and to prevent disruption of the correct unit
airflow pattern.
REGULAR DEALER MAINTENANCE
In addition to the type of routine maintenance you might be willing
to perform, your unit should be inspected regularly by a properly
trained service technician. An inspection (preferably each year, but
at least every other year) should include the following:
1. Inspection and, if required, cleaning of the outdoor and indoor
coils.
2. Inspection and, if required, cleaning of the indoor coil drain
pan.
3. Inspection and cleaning of blower wheel housing and motor.
4. Inspection of all supply-air and return-air ducts for leaks,
obstructions, and insulation integrity. Any problems found
should be resolved at this time.
5. Inspection of the unit base to ensure that no cracks, gaps, etc.,
exist which may cause a hazardous condition.
6. Inspection of the unit casing for signs of deterioration.
7. Inspection of all electrical wiring and components to assure
proper connection.
8. Inspection for leaks in the refrigerant circuit. Pressure-check
to determine appropriate refrigerant charge.
9. Operational check of the unit to determine working condi-
tions. Repair or adjustment should be made at this time.
Your servicing dealer may offer an economical service contract
that covers seasonal inspections. Ask for further details.
Complete service instructions can be found in the unit Installation,
Start-Up and Service Instructions.
Table 1—Indoor-Air Filter Data
UNIT SIZE FILTER SIZE
48XZ024-030 20x20x1
48XZ036 20x24x1
48XZ042-060 24x30x1
Fig. 2—Accessory Filter Rack Access Panel
C99094
ACCESS PANEL
FILTER ACCESS
PANEL*
*For accessory filter rack.
3

WARRANTY CERTIFICATE
Unit 48XZ has a limited warranty. Be sure to read the warranty
carefully to determine the coverage for your unit.
BEFORE YOU CALL FOR SERVICE ...
...check for several easily-solved problems.
If insufficient heating or cooling is suspected:
( ) Check the air filter for dirt. Check for blocked return-air or
supply-air grilles. Be sure they are open and unobstructed. If these
checks do not reveal the cause, call your servicing dealer.
If your unit is not operating at all, check the following list for
easy solutions:
( ) Check to be sure that your thermostat temperature selector is set
below the indoor temperature during the cooling season or above
the indoor temperature during heating season. Be sure the SYS-
TEM switch or MODE control is in the COOL or HEAT position
and not in the OFF position.
( ) If your unit still fails to operate, call your servicing dealer for
troubleshooting and repairs. Specify the model and serial numbers
of your unit. (Record them in this manual in the space provided.)
If the dealer knows exactly which unit you have, he may be able
to offer suggestions over the phone, or save valuable time through
knowledgeable preparation for the service call.
IN CASE OF TROUBLE
If you perform the steps above and unit performance is still
unsatisfactory, shut off the unit and call your dealer.
Dealer’s Name ______________________________________
Telephone__________________________________________
Unit Model_________________________________________
Unit Serial Number___________________________________
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
PC 101 Catalog No. 534–80126 Printed in U.S.A. Form OM48–17 Pg 41–04 Replaces: New
Copyright 2003 CARRIER Corp. • 7310 W. Morris St. • Indianapolis, IN 46231 om4817
Book 1 4
Tab 1 6