Guide Specifications - Carrier 50TFQ004 Product Data

Guide specifications

Packaged Rooftop Air-to-Air Heat Pump
with Electric Heat Option — Constant
Volume Application
HVAC Guide Specifications
Size Range: 3 to 10 Tons, Nominal Cooling
Carrier Model Number: 50TFQ
Part 1 — General
1.01 SYSTEM DESCRIPTION
Outdoor rooftop- or slab-mounted, electrically con-
trolled air-to-air heat pump utilizing a hermetic com-
pressor for heating and cooling duty. Unit shall
discharge supply air vertically or horizontally as shown
on contract drawings.
1.02 QUALITY ASSURANCE
A. Unit shall be rated in accordance with ARI Standards
210/240 and 270.
B. Unit shall be designed to conform to ASHRAE 15, lat-
est revision, and in accordance with UL 1995.
C. Unit shall be UL tested and certified in accordance with
ANSI Z21.47 Standard and UL listed and certified
under Canadian Standards as a total package for safety
requirements.
D. Roof curb shall be designed to conform to NRCA
Standards.
E. Insulation and adhesive shall meet NFPA 90A require-
ments for flame spread and smoke generation.
F. Unit casing shall be capable of withstanding Federal
Test Method Standard No. 141 (Method 6061)
500-hour salt spray test.
1.03 DELIVERY, STORAGE, AND HANDLING
Unit(s) shall be stored and handled per manufacturer's
recommendations.
Part 2 — Products
2.01 EQUIPMENT (STANDARD)
A. General:
Factory-assembled, single-piece air-to-air heat pump.
Contained within the unit enclosure shall be all factory
wiring, piping, controls, refrigerant charge (R-22), and
special features required prior to field start-up.
B. Unit Cabinet:
1. Unit cabinet shall be constructed of galvanized
steel, bonderized and coated with a baked enamel
finish on all externally exposed surfaces with
primer coated internal panels.
2. Indoor fan cabinet interior shall be insulated with a
minimum 1 / -in. thick flexible fiberglass insulation
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coated on the air side.
3. Cabinet panels shall be easily removable for ser-
vicing.
4. Holes shall be provided in the base rails for rigging
shackles to facilitate overhead rigging, and forklift
slots shall be provided to facilitate maneuvering.
5. Unit shall have a factory-installed, sloped conden-
sate drain pan made of a non-corrosive material,
providing a minimum
vertical and horizontal drains and shall comply
with ASHRAE 62.
6. Unit shall have factory-installed filter access panel
to provide filter access with tool-less removal.
7. Unit shall have standard thru-the-bottom power
connection capability.
3 / -in. connection with both
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C. Fans:
1. Indoor blower shall be of the direct- or belt-driven,
double inlet, forward-curved centrifugal type. Belt
drive shall include an adjustable-pitch motor
pulley.
2. Indoor blower shall be made from steel with a
corrosion-resistant finish and shall be dynamically
balanced.
3. Bearings shall be of the sealed, permanently lubri-
cated, ball-bearing type for longer life and lower
maintenance.
4. Outdoor fan shall be of the direct-driven propeller
type and shall discharge air vertically.
5. Outdoor fan shall have aluminum blades riveted to
corrosion-resistant steel spiders and shall be
dynamically balanced.
D. Compressor(s):
1. Fully hermetic type, internally protected.
2. Factory rubber shock-mounted and internally
spring mounted for vibration isolation.
E. Coils:
1. Outdoor and indoor coils shall have aluminum
plate fins mechanically bonded to enhanced cop-
per tubes with all joints brazed.
2. Tube sheet openings shall be belled to prevent
tube wear.
3. Indoor coil shall be of the face split design.
F. Refrigerant Components: Refrigerant circuit compo-
nents shall include:
1. Acutrol™ multiple independent circuit metering
system.
2. Service gage connections on suction, discharge,
and liquid line to charge, evacuate, and contain
refrigerant.
3. Accumulator.
4. Reversing valve.
G. Filter Section:
1. Standard filter section shall consist of factory-
installed low-velocity, throwaway 2-in. thick fiber-
glass filters of commercially available sizes.
2. Filter face velocity shall not exceed 300 fpm at
nominal airflows.
3. Filter section shall use only one size filter.
4. Filters shall be accessible through an access panel
with ''no-tool'' removal.
H. Controls and Safeties:
1. Unit Controls:
a. Unit shall be complete with self-contained low-
voltage control circuit.
b. Unit shall incorporate an outdoor coil defrost
system to prevent excessive frost accumulation
during heating duty, and shall be controlled as
follows:
1) Defrost shall be initiated on the basis of
time and coil temperature.
2) A 30/50/90-minute timer shall activate
defrost cycle only if coil temperature is low
enough to indicate a heavy frost condition.
3) Defrost cycle shall terminate when de-
defrost thermostat is satisfied and shall
have a positive termination time of
10 minutes.
c. Unit shall contain high-pressure, loss-of-
charge/low-pressure, and freeze protection
switches. It shall mount on factory-installed
Schrader fittings.
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