Carrier WeatherMaker 48A 020

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Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.

Catalog No. 04-53480495-01 Printed in U.S.A. Form 48A-22SI Pg 1 2-24 Replaces: 48A-21SI

Installation Instructions

CONTENTS

Page

SAFETY CONSIDERATIONS . . . . . . . . . . . . . . . . . . . 1

UNIT CONSIDERATIONS . . . . . . . . . . . . . . . . . . . . . . 3

Temporary Operation for a Completed Building . . . 3

Temporary Operation for an Under-Construction

Building . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

ACOUSTICAL CONSIDERATIONS . . . . . . . . . . . . . . . 4

Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Ductwork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Acoustic Insulation . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

INSTALLATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Step 1 — Provide Unit Support . . . . . . . . . . . . . . . . . 5

• ROOF CURB

• ALTERNATE UNIT SUPPORT

Step 2 — Rig and Place Unit . . . . . . . . . . . . . . . . . . . 5

• POSITIONING

• ROOF MOUNT

Step 3 — Field Fabricate Ductwork . . . . . . . . . . . . . 23

Step 4 — Make Unit Duct Connections . . . . . . . . . . 23

• 48A2, A3, A6, AND A7 UNITS

• 48A4, A5, A8, AND A9 UNITS

• 48A2020-050 UNITS

• 48A2060 UNITS

Step 6 — Trap Condensate Drain . . . . . . . . . . . . . . 24

Step 7 — Install Gas Piping . . . . . . . . . . . . . . . . . . . 24

• OPTIONAL STAGED GAS UNITS

Step 8 — Install Supply-Air Thermistors (Staged and

Modulating Gas Units Only) . . . . . . . . . . . . . . . . . 25

Step 9 — Make Electrical Connections . . . . . . . . . . 25

•POWER WIRING

• FIELD POWER SUPPLY

• FIELD CONTROL WIRING

Step 10 — Make Outdoor-Air Inlet Adjustments . . 29

• ECONOMIZER AND FIXED OUTDOOR AIR DAMPER

Step 11 — Position Power Exhaust/Barometric Relief

Damper Hood . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Step 12 — Route VAV Static Pressure Sensors . . . 33

• VAV DUCT PRESSURE TRANSDUCER

• VAV BUILDING PRESSURE TRANSDUCER

Step 13 — Install All Accessories . . . . . . . . . . . . . . 33

• FIELD-FABRICATED WIND BAFFLES

• DUCTWORK

BACnet

Communication Option Wiring . . . . . . . . 36

• WIRING THE UPC OPEN CONTROLLER TO THE MS/

TP NETWORK

• MS/TP WIRING RECOMMENDATIONS

Using ZS Sensor or an Equipment Touch . . . . . . . 38

SAFETY CONSIDERATIONS

Installation and servicing of air-conditioning equipment can be

hazardous due to system pressure and electrical components. Only

trained and qualified service personnel should install, repair, or

service air-conditioning equipment.

Untrained personnel can perform basic maintenance functions of

cleaning coils and filters and replacing 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, including ANSI (American National

Standards Institute) Z223.1. Wear safety glasses and work gloves.

Use quenching cloth for unbrazing operations. Have fire

extinguisher available for all brazing operations.

It is important to recognize safety information. This is the safety-

alert symbol . When you see this symbol on the unit and 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 hazards

which could result in personal injury or death. CAUTION is used

to identify unsafe practices, which may 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.

WARNING

Before performing service or maintenance operations on unit,

turn off main power switch to unit. Electrical shock could

cause personal injury.

WARNING

Improper installation, adjustment, alteration, service, or main-

tenance can cause property damage, personal injury, or loss of

life. Refer to the User’s Information Manual provided with this

unit for more details.

WARNING

UNIT OPERATION AND SAFETY HAZARD

Failure to follow this warning could cause personal injury,

death and/or equipment damage.

R-410A refrigerant systems operate at higher pressures than

standard R-22 systems. Do not use R-22 service equipment or

components on R-410A refrigerant equipment.

WeatherMaker

48A020-060

Single Package Gas Heating/Electric Cooling

Rooftop Units with ComfortLink Controls

and Puron

Refrigerant (R-410A)

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The device manual describes the WeatherMaker® 48A020-060 Single Package Gas Heating/Electric Cooling Rooftop Units with ComfortLink Controls and Puron® Refrigerant (R-410A). This is a commercial HVAC unit designed for heating and cooling applications in buildings.

Function Description:

The WeatherMaker® 48A series units are single-package rooftop units that provide both gas heating and electric cooling. They are equipped with ComfortLink Controls for integrated system management. These units utilize Puron® (R-410A) refrigerant, which operates at higher pressures than standard R-22 systems. The units are designed for various airflow configurations, including thru-the-bottom and side supply/return, and can be adapted for different building layouts. They support various control options, including constant volume (CV), variable air volume (VAV), staged air volume (SAV™), variable volume variable temperature (VVT®), or Carrier TEMP system control operation. They can operate standalone with a thermostat or space sensor, or as part of a network application with Carrier Comfort Network® (CCN) or other building management systems. Advanced features like demand-controlled ventilation with CO2 sensors, economizer and economizer with changeover control, staged gas heat, building and duct static pressure control, fire shutdown, smoke control, diagnostics, and monitoring are supported.

Important Technical Specifications:

Refrigerant: Puron® (R-410A).
Operating Pressures: Higher than standard R-22 systems, requiring R-410A specific service equipment.
Power Wiring: Units are factory wired for the specified voltage on the nameplate. Main power terminal block is suitable for aluminum or copper wire.
Control Wiring: Low-voltage control wiring (24-v) is provided. CCN communication bus wiring requires shielded, 3-conductor cable (20 AWG minimum stranded, tinned copper) with specific insulation and jacket materials (PVC, PVC/nylon, vinyl, Teflon™, or polyethylene).
Gas Supply: Natural gas pressure at the unit connection must be between 5 in. wg and 13.5 in. wg. Gas piping should be sized for a maximum 0.5-in. wg pressure drop.
Condensate Drain: Requires a trapped drain at least 4 inches deep to prevent freeze-up.
Airflow: Supply fan can operate at constant speed or variable speed (VAV units). Airflow rates vary by unit size and motor horsepower, with nominal CFM ranging from 8,000 to 24,000 for evaporator fans and 19,500 to 40,000 for condenser fans.
Filters: Mixed-air filters are typically 20x24x2 inches (standard) or 20x20x4 / 20x24x4 inches (pleated). Outdoor-air filters are 16x25x2 or 20x25x2 inches.
Motor Types: Evaporator fans use centrifugal type with belt drive. Condenser fans use propeller type. Power exhaust fans use direct drive, single-phase motors with forward-curved fan wheels.
Weights: Operating weights vary significantly by unit size and configuration, ranging from approximately 4689 lbs (020 size) to 8676 lbs (060 size) for base units, with additional weights for accessories like economizers, power exhaust, electric heat, and roof curbs.
Dimensions: Overall dimensions vary by unit size, with lengths up to 308.64 inches (7839 mm) and widths up to 162.75 inches (4126 mm) for larger units.
Clearances: Minimum clearances are specified for top, condenser coil side, economizer side, heat side, and filter access side (e.g., 10 ft for filter access side for evaporator coil removal).

Usage Features:

ComfortLink Controls: Allows for sophisticated control strategies, including multi-zone VAV, VVT, and thermostat/space temperature sensor integration.
Temporary Operation: While not recommended for under-construction buildings, temporary operation for completed buildings is possible after a start-up, with specific guidelines to prevent damage (e.g., maintaining adequate airflow, locking out unused systems).
Acoustical Considerations: Recommendations are provided to minimize sound transmission, such as unit placement away from sound-sensitive areas, use of flexible connectors, trailing edge turning vanes in ductwork, and acoustic insulation.
Ductwork Connections: Units can be configured for thru-the-bottom or side supply/return duct connections. Field-fabricated ductwork is required, with specific guidelines for attachment and air distribution.
Economizer and Fixed Outdoor Air Damper: Hoods are provided for outdoor air intake, with assembly instructions for proper sealing and filter installation.
Power Exhaust/Barometric Relief Damper: Optional accessories that can be field-installed in the return ductwork, with specific mounting and wiring instructions.
VAV Static Pressure Sensors: Includes transducers for duct and building static pressure, requiring field-supplied plastic tubing connections.
BACnet® Communication Option: Allows integration with building management systems via MS/TP network, with detailed wiring specifications and recommendations for cable types and terminators.
ZS Sensor or Equipment Touch: These devices connect to the UPC's RNET connector for space temperature feedback and equipment control.

Maintenance Features:

Service Access: Clearances are specified to ensure adequate access for servicing, including filter and evaporator coil removal.
Electrical Grounding: Units must be electrically grounded in accordance with local codes and NEC ANSI/NFPA 70.
Phase Imbalance Monitoring: Important to check supply voltage phase imbalance (must be less than 2%) to prevent damage to electrical components.
Transformer Rewiring: Instructions are provided for rewiring transformers on 208/230-v units if operating with a 208-v power supply.
Field-Fabricated Wind Baffles: Recommended for vertically oriented condenser coils in environments with prevailing winds or low temperatures to ensure proper cooling cycle operation.
Regular Maintenance: For extended temporary operation, regular maintenance is required to ensure proper functioning and maintain warranty coverage.
Safety Precautions: Emphasizes the importance of trained personnel for installation and servicing, wearing safety glasses and gloves, and following all safety codes. Warnings are provided for hazards related to system pressure, electrical shock, fire, explosion, and carbon monoxide poisoning.