50XT
Infinity 15t SEER Single---Packaged Heat Pump System
with Puronr (R---410A) Refr ige rant
Single Phase
2---5 Nominal Tons (Sizes 024 --- 060)
Product Data
Comfort Heat Pump System with IdealHumidityt featuring
Infinityt control variable--speed blower motor and two--stage
cooling and heating that provides greater comfort, humidity
control, and energy efficiency.
Variable-- speed blower motors provide better comfort and energy
efficiency. You can expect up to 30 times better dehumidification;
economical constant airflow which provides improved indoor air
quality and more even temperatures from room to room; and
reduced indoor noise due to lower air velocity. In addition, you’ll
realize improved installation flexibility with 3 different airflow
choices for best overall comfort.
Easy installation
Factory-- assembled package is a compact, fully self-- contained heat
pump unit that is pre-- wired, pre--piped, and pre--charged for
minimum installation expense. 50XT units are available in a
variety of standard capacity ranges. Units install easily on a rooftop
or at ground level.
Durable, dependable components
Compressors have two stages of cooling and heating and are
designed for high efficiency. Each compressor is hermetically
sealed against contamination to help promote longer life and
dependable operation. Vibration isolation provides quiet operation.
A05307
Fig. 1 -- Unit 50XT
Single--Packaged Products with energy--saving features and
®
refrigerant.
Puron
S Up to 15.5 SEER
S Up to 8.0 HSPF
S Up to 12 EER at 95°F(35°C) OD
S Low Sound Levels
S Variable--Speed Blower (Standard)
S Factory--Installed TXV
S Two--stage cooling and heat pump operation
FEATURES/BENEFITS
One--piece Heat Pump unit with optional electric heater, low
installation cost, dependable performance and easy maintenance.
Efficient operation
High--efficiency design with SEERs (Seasonal Energy Efficiency
Ratio) of up to 15.5.
®
Puron
refrigerant designed to help protect the environment. Puron is an
HFC refrigerant which does not contain chlorine that can harm the
ozone layer. Puron refrigerant is in service in millions of systems
proving highly reliable, environmentally sound performance.
environmentally-- sound refrigerant is Carrier’s unique
Compressors have internal high-- pressure and overcurrent
protection.
Convertible du ct configuration
Unit is designed for easy use in either downflow or horizontal
applications. Each unit is easily converted from horizontal to
downflow with two duct covers (available as an accessory).
Downflow operation is easily provided in the field to allow vertical
ductwork connections. The basepan utilizes knockout style seals
on the bottom openings to ensure a positive seal in the horizontal
airflow mode.
Direct-- drive, variable--speed blower motor is standard on all
50XT models.
Direct--drive, PSC condenser fan motors are designed to help
reduce energy consumption and provide for cooling operation
downto55°F (12.7°C) outdoor temperature. Low--ambient
cooling is available below 55°F (12.7°C) when low-- ambient
cooling is enabled in the User Interace (UI). Motormaster
low--ambient kit is not required.
Infinityt User Interface is designed to work as a system with
Carrier’s single--packaged product.
Refrigerant system is designed to provide dependability. Liquid
refrigerant filter driers are used to promote clean, unrestricted
operation. Each unit leaves the factory with a full Puron refrigerant
charge. Refrigerant service connections make checking operating
pressures easier.
Indoor and outdoor coils are computer designed for optimum
heat transfer and cooling efficiency. The indoor coil is fabricated
from copper tube and aluminum fins and is located inside the unit
®
II
1
for protection against damage. The outdoor coil is internally
mounted on the top tier of the unit. Copper fin coils and pre-- coated
fin coils are available from the factory by special order. These coils
are recommended in applications where aluminum fins are likely to
be damaged due to corrosion. They are ideal for seacoast
applications.
Thermostatic expansion valve (TXV) —A hard-- shutoff, balance
port TXV maintains a constant superheat at the evaporator exit
(cooling cycle) resulting in higher overall system efficiency.
High-- and low--pressure switches give added safety and
reliability to the compressor.
Low sound ratings ensure a quiet indoor and outdoor
environment with sound ratings as low as 75 dBA.
Easy to service cabinets provide easy single--panel accessibility to
serviceable components during maintenance and installation. The
basepan, with integrated drain pan, provides easy ground level
installation with or without a mounting pad. Convenient handholds
are provided to manipulate the unit on the job site. A nesting
feature ensures a positive basepan to roof curb seal when the unit is
roof mounted. A convenient 3/4--in. wide perimeter flange makes
frame mounting on a rooftop easy.
Louvered grille provides hail and vandalism protection for the
coil.
Cabinets are constructed of heavy--duty, phosphated, zinc--coated,
pre--painted steel capable of withstanding 500 hrs of salt spray.
Interior surfaces of the evaporator and electric heater compartments
are insulated with cleanable, semi-- rigid insulation board, which
keeps the conditioned air from being affected by the outdoor
ambient temperature and provides improved indoor air quality.
(Conforms to American Society of Heating, Refrigeration and Air
Conditioning Engineers No. 62P.) The sloped drain pan minimizes
standing water in the unit, which is provided with an external
drain.
Short--cycling protection for the compressor is incorporated into
our Infinity heat pump/air conditioner dual capacity control board
ensuring a five--minute delay before restarting compressor after
shutdown for any reason.
Limited Warranty—Standard 5--year limited warranty on all parts
and10--yearlimitedwarrantyoncompressor.
} Rated in accordance with U.S. Government DOE (Department of Energy) test procedures a nd/or ARI Standards 210/240.
** Tested in accordance with ARI Standard 270 ---95 (not listed in ARI).
NOTES:
1. Ratings are net values, reflecting the effects of circulating fan heat. Ratings are based on:
Cooling Standard: 80°F (26.6°C) db, 67°F (19.4°C) wb indoor entering ---air temperature and 95°F(35°C) db outdoor entering---air temperature.
2. Before purchasing this appliance, read important energy cost and efficiency information available from your retailer.
LEGEND
dBA—Sound Levels (decibels)
db—Dry Bulb
SEER—Seasonal Energy Efficiency Ratio
wb—Wet Bulb
COP—Coefficient of Performance
HSPF—Heating Season Performance Factor
Motor HP (RPM)1/8 (825)1/8 (825)1/8 (825)1/8 (825)1/4 (1100)1/3 (1110)
INDOOR COIL
Rows…Fins/in.3…173…173…173…173…174…17
50XT
Face Ar ea ( sq. ft.)3.73.74.74.75.75.7
INDOOR FAN
Nominal Airflow (Cfm)
ComfortVariable based on Comfort Settings (see User Interface instruction s for more information).
Efficiency7008751050122514001750
Max80010001200140016002000
L O S S --- OF --- C H A R G E / L O W --- P R E S S U R E S W I T C H
(Liquid Line) (psig)
Cutout23 ± 5
Reset (Auto)55 ± 5
RETURN ---AIR FILTERS Throwaway (in.)*
*Recommended filter sizes for field---installed air filter grilles mounted on th e wall or ceiling of the conditioned structure. Required filter sizes shown are based
on the larger of the ARI (Air Conditioning and Refrigeration Institute) rated cooling airflow or the heating airflow velocity of 300 ft/minute for throwaway type or
450 ft/minute for high ---capacity type. Air filter pressure drop for non ---standard filters must not exceed 0.08 IN. WC.
NOTE: Tested in accordance with ARI Standard 270 --- 95 (not listed in ARI).
STANDARD
RATING
(dBA)
TYPICAL OCTAVE BAND SPECTRUM (dBA) (without tone adjustment)
1252505001000200040008000
4
OPTIONS AND ACCESSORIES
Factory--installed options
Coil options include tin--plated* indoor hairpins, copper/copper
and vinyl--coated construction for refrigerant coils. Units are
shipped standard with copper tube/aluminum fin construction. See
model number nomenclature for coil options.
*Tin--plated indoor coils are built with special hairpins that are
designed to resist both general pitting corrosion and excessive
indoor corrosion (Formicary Corrosion).
Field--installed accessories
Manual Air Damper (25% open)
Electric Heaters
Filter Rack
Flat Roof Curbs (8--in. and 14--in.) (203 mm and 256 mm)
Square--to--Round Duct Transition Kit
Infinityt User Interface
Crankcase Heater
Lifting Kit
Compressor Hard Start Kit
Manual outside air damper includes hood and filter rack with
adjustable damper blade for up to 25% outdoor air.
Electric heaters provide additional heat in the unit when required.
Each package has a heater module that slides into the controls
Electric Heaters
CATALOG
ORDERING NO.
CPHEATER080A003.8 / 5.0NO1XXX
CPHEATER081A003.8 / 5.0YES1XXX
CPHEATER083A005.4 / 7.2YES1XXXXXX
CPHEATER085A007.5 / 10.0YES1XXXXXX
CPHEATER087A0011.3 / 15.0YES2XXXXX
CPHEATER089A0015.0 / 20.0YES2XXX
NOTE
Electric heaters are rated at 240v. Refer to Multiplication Factors table for oth er voltages.
X=Approved combination
NOMINAL
CAPACITY
(kW)FUSEDSTAGES243036424860
208/240 — SING LE PHASE (60 Hz)
compartment. Heater sizes range from 5.0 to 20.0 kW. The electric
heater design allows the use of a single--point power supply for the
entire unit, resulting in lower installed costs.
Flat roof curbs in both 8 in. (203 mm) and 14 in. (256 mm) sizes
are available for roof mounted applications.
Square--to-- round duct transition kit enables 024-- 048 size units
to be fitted to 14 in. round ductwork.
Infinity User Interface coupled with the system’s variable--speed
indoor blower delivers Carrier’spatentedIdealHumidity
technology that allows for even greater humidity control. Along
with more precisely controlling temperature and humidity, the
Infinity User Interface offers full seven--day programmability
allowing you to further customize your comfort and energy
savings.
Lifting kit includes 4 metal brackets that are available to assist in
lifting this product onto a roof application.
Crankcase heaterprovides anti--floodback protection for
low--load cooling applications.
Filter rackfeatures easy installation, serviceability, and
high--filtering performance for vertical or horizontal applications.
Compressor hard start kitassists compressor start--up by
providing additional starting torque on single phase units and
prolongs compressor motor life.
USED WITH SIZES
50XT
5
FILTER RACK
EVAPORATOR
COIL
50XT
BEND FLANGE AT 90°-SCREW TO
DIVIDER WITH 1-IN. SCREW
6. When unit mounting screw is used ( see Note A), a retainer br acket must be used as well. This bracket must also be used when required by code for hurricaneorseismic
conditions. This bracket is available through Micrometl.
A05308
G
IN. (MM)
9
50XT SUGGESTED RIGGING
DETAIL
A
-in. (914 mm)
A06296
A06298
SELECTION PROCEDURE
Determine cooling and heating requirements at design
conditions
Given:
REQUIRED COOLING CAPACITY (TC)34,500 BTUH......
SENSIBLE HEAT CAPACITY (SHC)24,000 BTUH.........
REQUIRED HEATING CAPACITY (SHC)36,000 BTUH.....
CONDENSER ENTERING AIR TEMPERATURE 95°F(35°C)
INDOOR--AIR TEMPERATURE80°F (26.6°C) EDB, 67°F...
(19.4°C) EWB
EVAPORATOR AIR QUANTITY1200 CFM...............
ELECTRICAL CHARACTERISTICS230--1--60.............
Select unit based on required cooling capacity
Enter Net Cooling Capacities table at condenser entering
temperature of 95°F(35°C). The 036 unit at 1200 cfm and 67°F
(19.4°C) ewb (entering wet bulb) will provide a total capacity of
34,600 Btuh and a SHC of 24,220 Btuh. Calculate SHC correction,
if required, using Note 4 under Cooling Capacities tables.
CABINETMODEL
Small
Large
NOTE: See dimensional drawing for corner weight distribution. Corner
weights shown on drawing are based on unit--- only weights and do
not include packaging.
Enter the Electric Heater table on page 5 for 208/230v,
single--phase, unit. The 7.2--kW heater at 240v most closely
satisfies the heating required. To calculate kW at 230v, multiply the
heater kW by multiplication factor 0.92 found in the Multiplication
Factors table on page 29.
7.2 kW x 0.92 = 6.6 kW
6.6 kW x 3414 Btuh/kW = 22,532 Btuh
Total unit heating capacity is 39,342 Btuh
(16,810 + 22,532).
Select unit that corresponds to power source available
The Electrical Data table shows that the unit is designed to operate
at 208/230--1--60.
Select electric heat
Enter the 036 unit Heating Extended Performance table at 1200
cfm. At 70°F (21.1°C) return indoor air and 20°F(--6.6°C) air
entering outdoor coil, the integrated heating capacity is 16,810
Btuh. (Select integrated heating capacity value since deductions for
outdoor--coil frost and defrosting have already been made. No
correction is required.)
The required heating capacity is 36,000 Btuh. Therefore, at least
19,190 Btuh additional electric heat is required.
Determine additional electric heat capacity in kW.
Cap. — Heating Capacity (1000 Btuh) (Includes Indoor--Fan Motor Heat)
db —DryBulb
kW — Total Power Input (Includes Compressor Motor Power Input Outdoor--Fan Motor Input, and Indoor--Fan Motor Input)
rh— Relative Humidity
NOTES:
Integrated capacity is maximum (instantaneous) capacity less the effect of frost on the outdoor coil and the heat required to defrost it.
28
PERFORMANCE DATA (CONT)
Multiplication Factors
Heater kW
Rating
240
LEGEND
BF— Bypass Factor
edb— Entering Dry-- Bulb
Ewb— Entering Wet-- Bulb
kW — Total Unit Power Input
ldb— Leaving Dry-- Bulb
lwb— Leaving Wet--Bulb
SHC— Sensible Heat Capacity (1000 Btuh)
TC — Total Capacity (1000 Btuh) (net)
*At 75°F (23.8°C) entering dry bulb (Tennessee Valley Authority
[TVA] rating conditions); all other at 80°F (26.6°C) entering dry
bulb.
COOLING NOTES:
1. Ratings are net; they account for the effects of the evaporator
fan motor power and heat.
2. Direct interpolation is permissible. Do not extrapolate.
3. The following formulas may be used:
Voltage Distribution
V/3/60
200.69
208.75
230.92
2401.00
Multiplication Factor
Example: 15.0 kW (at 240v) heater on 208v
= 15.0 (.75 mult factor)
= 11.25 capacity at 208v
Sensible capacity
t
ldb =tedb
t
lwb =
h
lwb =he w b ---
1.10 x cfm
--
Wet--- bulb temperature corresponding to enthalpy
air leaving evaporator coil (
total capacity (Btuh)
4.5 x cfm
(Btuh)
h
lwb)
Where:hewb = Enthalpy of air entering evaporator coil
4. The SHC is based on 80_F (26.6_C) edb temperature of air
entering evaporator coil. Below 80_F (26.6_C) edb, subtract (corr
factor x cfm) from SHC.
Above 80_F (26.6_C) edb, add (corr factor x cfm) to SHC.
CorrectionFactor=1.10x(1+BF)x(edb+80).
5. Integrated capacity is maximum (instantaneous) capacity less the
effect of frost on the outdoor coil and the heat required to defrost it.
50XT
29
Wet coil air delivery -- low stage
208/230 VOLT
UNIT
SIZE
024
030
036
042
048
060
SYSTEM SETTING
COMFORT (D efault)Variable based on Comfort Settings
EFFICIENCY525525525525525525525525525525
MAX600600600600600600600600600600
COMFORT (D efault)Variable based on Comfort Settings
EFFICIENCY613613613613613613613613613613
MAX700700700700700700700700700700
COMFORT (D efault)Variable based on Comfort Settings
EFFICIENCY743743743743743743743743743743
MAX850850850850850850850850850850
COMFORT (D efault)Variable based on Comfort Settings
EFFICIENCY853853853853853853853853853853
MAX975975975975975975975975975975
COMFORT (D efault)Variable based on Comfort Settings
EFFICIENCY963963963963963963963963963963
MAX1100110011001100110011001100110011001100
COMFORT (D efault)Variable based on Comfort Settings
Condensate trap — A 2-- in. (51 mm) condensate trap must be field
supplied.
1” (25mm) MIN.
TRAP
OUTLET
2” (50mm) MIN.
Ductwork— Securedownflow discharge ductworkto roof curb.For
horizontal discharge applications, attach ductwork to unit with
flanges.
Balance Point Worksheet
To convert a unit to downflow discharge — Units are equipped
withfactory--installedinserts in the downflow openings.Remove the
inserts similar to removing an electrical knock--out. Leave on duct
covers to seal the horizontal discharge openings in the unit. Units
installed in horizontal discharge orientation do not require duct covers.
Minimum cooling ambient operating temperature —Allstandard units have a minimum ambient operating temperature of 55°F
(12.7°C). With low--ambient cooling enabled at the UI, units can operate at temperatures down to 0°F (--17.7°C).
Maximum operating outdoor air temperature — Maximum outdoor operating air temperature for cooling is 125°F (51.6°C).
70
Based on Entering Indoor Air of 70 Deg. F and Rated CFM
60
50
40
1000BTUH
30
20
Building Heat Loss, 1000BTUH
Unit Integrated Heating Capacity,
10
0
-20-100102030405060
Outdoor Air Temp (Deg F)
060
048
042
036
030
024
C03008
32
ELECTRICAL DA TA
SINGLE POINT POWER
SUPPLY
UNIT SIZE
V--PH--HZ
VO LTAG E
RANGE
COMPRESSOROFM
FLA
IFM
FLA
ELECTRIC HEAT
NOMINAL
MINMAXRLALRAkW*
FLAMCAMOCP
-- / ---- / --24.3/24.335/35
024208/230--1--6018725315.352.00.94.3
3.8/5.018.1/20.846.9/50.350/60
5.4/7.226.0/30.056.8/61.860/70
7.5/10.036.1/41.769.4/76.470/80
-- / ---- / --26.2/26.240/40
3.8/5.018.1/20.848.7/52.250/60
030208/230--1--6018725316.870.00.94.3
5.4/7.226.0/30.058.7/63.760/70
7.5/10.036.1/41.771.3/78.380/80
11.3/15.054.2/62.593.9/104.3100/110
-- / ---- / --28.6/28.645/45
3.8/5.018.1/20.851.2/54.660/60
036208/230--1--6018725316.782.00.96.8
5.4/7.226.0/30.061.1/66.170/70
7.5/10.036.1/41.773.7/80.780/90
11.3/15.054.2/62.596.3/106.7100/110
-- / ---- / --34.9/34.950/50
3.8/5.018.1/20.857.5/60.960/70
042208/230--1--6018725321.896.00.96.8
5.4/7.226.0/30.067.4/72.470/80
7.5/10.036.1/41.780.0/87.090/90
11.3/15.054.2/62.5102.6/113.0110/125
15.0/20.072.2/83.3125.2/139.1150/150
-- / ---- / --43.1/43.160/60
3.8/5.018.1/20.865.7/69.170/70
048208/230--1--6018725327.896.01.56.8
5.4/7.226.0/30.075.6/80.680/90
7.5/10.036.1/41.788.2/95.290/100
11.3/15.054.2/62.5110.8/121.2125/125
15.0/20.072.2/83.3133.4/147.3150/150
-- / ---- / --45.2/45.260/60
3.8/5.018.1/20.867.7/71.270/80
060208/230--1--6018725327.3118.01.99.1
5.4/7.226.0/30.077.6/82.780/90
7.5/10.036.1/41.790.3/97.2100/110
11.3/15.054.2/62.5112.9/123.3125/125
15.0/20.072.2/83.3135.4/149.3150/150
*Heater capacity (kW) based on heater voltage o f 208v & 240v. If power distribution voltage to unit varies from rated heater vol tage, heater kW will vary accordingly.
1. In compliance with NEC (National Electrical Code) requirements
for multimotor and combination load equipment (refer to NEC
Articles 430 and 440), the overcurrent protective device for the
unit shall be Power Supply fuse . The CGA (Canadian Gas
Association) units may be fuse or circuit breaker.
2. Minimum wire size is based on 60 C copper wire. If other than
60 C wire is used, or if length exceeds wire length in table,
determine size from NEC.
®
33
TYPICAL WIRING SCHEMATIC — 230--1--60
A08201
34
CONTROLS
Sequence of Operation
The 50XT packaged heat pump is designed for installation with a
communicatingUI. This unit will not respondto commandsprovided
by a common thermostat except under certain emergency situations.
The UI uses temperature, humidity and other data supplied from
indoor and outdoor system components to controlheating or cooling
system for optimum comfort. The unit will be commanded by the UI
to supply airflow. The unit will operate the indoor fan at requested
airflow for most modes.
The nominal requested airflow in high stage will be 350 cfm per ton
of nominal cooling capacity as defined by unit size. Actual airflow
request will be adjusted from nominal using indoor and outdoor
temperature and indoor humidity data to optimize the system
operation for occupant comfort and system efficiency. Refer to UI
literature for further system control details.
Airflow during electric heater operation must be greater than a
minimum level for safe operation. If UI instructs unit to turn on
electric heat and the requested airflow is less than the minimum level
the fan coil control will override requested value.
NOTE: Once the compressor has started and then has stopped, it
should not be started again until 4 minutes have elapsed. The cooling
cycle remains “on” until the room temperature drops to point that is
slightly below the cooling control setting of the UI.
COOLING AND HEATING OPERATION
With a call for first stage cooling, the outdoor fan, reversing valve,
and low stage compressor are energized. If low--stage cannot
satisfy cooling demand, high--stage cooling is energized by the UI.
After second stage is satisfied, the unit returns to low--stage
operation until first stage is satisfied or until second stage is
required again. When both first stage and second stage cooling are
satisfied, the compressor will shut off. The reversing valve will
remain energized until the control board power is removed or a call
for heating is initiated. With a call for heating, the outdoor fan and
compressor are energized. The compressor will operate in high or
low stage operation, as needed, to meet the heating demand. When
the heating demand is satisfied, the compressor and fan will shut
off. The reversing valve is de--energized in the heating mode.
NOTE: When two--stage unit is operating at low--stage, system
vapor (suction) pressure will be higher than a standard single-- stage
system or high-- stage operation.
NOTE:Outdoor fan motor will continue to operate for one
minute after compressor shuts off, when outdoor ambient is greater
than or equal to 100°F(38°C).
UTILITY INTERFACE WITH INFINITY CONTROL
The utility curtailment relay should be connected to factory
supplied pigtails (PINK connected to R, VIOLET connected to Y2
on the control board) located in the low voltage splice box (see
Typical Wiring Schematic ). This input allows a power utility
device to interrupt compressor operation during peak load periods.
When the utility sends a signal to shut the system down, the UI will
display “Curtailment Active”.
Infinity Controlled Low Ambient Cooling
NOTE: When this unit is operating below 55_F (12.7°C) outdoor
temperature, provisions must be made for low ambient operation.
This unit is capable of low ambient cooling down to 0_F
(--17.7°C)ONLY when using the Infinity control. A low ambient kit
isnot required,and theoutdoorfan motor does not need to be replaced
for Infinity controlled low ambient operation. Low ambient coolingmust be enabled in the UI set-- up. Fan may not begin to cycle until
about 40_F(4.4°C) OAT. Fan will cycle based on coil and outdoor
air temperature.
35
GUIDE SPECIFICATIONS
SINGLE--PACKAGED HEAT PUMP UNITS
CONSTANT VOLUME APPLICATION
HVAC GUIDE SPECIFICATIONS
SIZE RANGE:2 TO 5 TONS, NOMINAL (COOLING)
MODEL NUMBER: 50 XT
PART I -- GENERAL
SYSTEM DESCRIPTION
Outdoor rooftop or ground mounted heat pump unit utilizing a
hermetic,2--stagescroll compressor for heatingand cooling duty
and optionalelectric heating. Unit shall discharge supply airvertically or horizontally as shown on contract drawings. Outdoor
fan/coil section shall have a draw--thru design with vertical discharge for minimum sound levels.
QUALITY ASSURANCE
A. Unit shall be rated in accordance with ARI Standards
210/240 and 270.
B. Unit shall be designed in accordance with UL Standard
1995.
C. Unit shall be manufactured in a facility registered to ISO
9001 manufacturing quality standard
D. Unit shall be UL listed and c--UL certified as a total
package for safety requirements.
E. Roof curb shall be designed to conform to NRCA
Standards.
F. Insulation and adhesives shall meet NFPA90A
requirements for flame spread and smoke generation.
G. Cabinet insulation shall meet ASHRAE Standard 62P.
DELIVERY, STORAGE, AND HANDLING
Unit shall be stored and handled per manufacturer’s recommendations.
PART 2-- PRODUCTS
EQUIPMENT
A. General:
Factory--assembled, single--piece, heat pump. Contained within
theunit enclosure shallbe allfactory wiring,piping, controls, refrigerantcharge (R--410A), and special features required prior to
field start--up.
B. Unit Cabinet:
1. Unit cabinet shall be constructed of phosphated,zinc--coated,
prepainted steel capable of withstanding 500 hrs of salt spray.
2. Normal service shall be through a single removable cabinet
panel.
3. The unit shall be constructed on a rust proof unit base that has
an externally trapped, integrated sloped drain pan.
4. Indoor fan compartment top surface shall be insulated with a
minimum 1/2 --in. (13 mm)thick, flexible fiberglass
insulation, coated on the air side and retained by adhesive and
mechanical means. The indoor wall sections will be insulated
with a foil-- faced insulation capable of being wiped clean.
Aluminum foil--faced fiberglass insulation shall be used in the
entire indoor air cavity section.
5. Unit shall have a field--supplied condensate trap.
C. Fans:
1. The indoor fan shall be variable--speed motor and control, as
shown on equipment drawings.
2. Fan wheel shall be made from steel, be double--inlet type. It
shall have forward--curved blades with a corrosion--resistant
finish and shall be dynamically balanced.
3. Outdoor fan shall be of the direct--driven propeller type with
aluminum blades, riveted to corrosion--resistant steel spiders.
It shall be dynamically balanced,and discharge air vertically.
2. Scroll compressors shall be standard on all units.
3. Compressor Protection:
Defrost control shall protect compressor by preventing
“short cycling.”
E. Coils:
1. Indoor and outdoor coils shall have aluminum plate fins
mechanically bonded to seamless copper tubes with all joints
brazed.
2. Tube sheet openings shall be bellied to prevent tube wear.
F. Refrigerant Metering Device:
Refrigerant metering device shall be o f the single body,
fixed orifice feed type (outdoor) and TXV (indoor).
G. Filters:
Filter section shall consist of field --installed, throw-- away,
1--in. thick fiberglass filters of commercially available sizes.
H. Controls and Safeties:
1. Unit controls shall be complete with self-- contained low
voltage control circuit.
2. Units shall incorporate an internal compressor protector that
provides reset capability.
3. Unit shall provide high-- and low-- /loss--of--charge pressure
safety protection.
I. Operating Characteristics:
1. Unit shall be capable of starting and running at 125°F
(51.6_C) ambient outdoor temperature, exceeding maximum
load criteria of ARI Standard 240.
2. Compressor shall be capable of operation down to 55°F
(12.7_C) ambient outdoor temperature in cooling and --10°
in heating.
3. Unit shall be capable of low--ambient cooling (below 55_F
(12.7_C) ambient outdoor temperature) with low--ambient
cooling enabled on the UI.
J. Electrical Requirements:
Allunit powerwiring shallenter unit cabinet at a single location.
K. Motors:
1. Compressor motors shall be of the refrigerant--cooled type
with line--break thermal and current overload protection.
2. All fan motors shall have permanently lubricated bearings and
inherent automatic-- reset thermal overload protection.
3. Outdoor fan motor shall be totally enclosed.
L. Grille
1. Louvered Grille:
Louvered grille shall be standard on all units.
F
36
GUIDE SPECIFICATIONS (CONT)
M. Special Features:
1. Coil Options:
Shall include factory--installed optional tin--plated indoor
copper/copper and vinyl-- coated refrigerant coils.
2. Flat Roof Curb:
Curbs shall have seal strip and a wood nailer for flashing and
shall be installed per manufacturer’s instructions.
3. Manual Outdoor Air Damper:
Package shall consist of damper, bird screen, and rain hood
which can be preset to admit outdoor air for year-- round ventilation.
4. Infinityt User Interface:
To provide for two--stageheat pump heating, two--stagecooling, and electric (auxiliary) heat, in addition to manual or automatic changeover and indoor fan control.
5. Low --Ambient Cooling:
Low--ambient cooling must be enabled in the UI setup to allow unit to operate down to 0°F(--17_C) outdoor ambient
temperature in cooling.
6. Filter Rack Kit:
Shall provide filter mounting for downflow and horizontal
applications.
7. Square-- To--Round Duct Transitions:
Shall have the ability to convert the supply and return open-
ings from rectangular to round (024--048 sizes only).
8. Crankcase Heater:
Shall provide anti-- floodback protection for low--load cool-
ing applications. (Standard on 042--060 sizes.)
9. Electric heaters:
a. Electric heater shall be available as a field--installed
option.
b. Heater elements shall be open--wire type, adequately
supported and insulated with ceramic bushings.
c. Electric heater packages must provide single--point
power connection capability.
10. Compressor Hard Start Kit:
Shall be available to give a boost to the compressor motor at
each start--up.
37
Copyright 2008 Carrier Corp. D 7310 W. Morris St. D Indianapolis, IN 46231Printed in U.S.A.Edition Date: 06/08
Manufacturer reserves the right to change, at any time, specifications and designs without notice and without obligations.
Catalog No: 50XT --- 04PD
Replaces: 50XT--- 3PD
38
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