Carrier 48NLT - User Manual

48M.T, NMT, NET, NHT AND NVT 018-060
Packaged Heating/Cooling Units
HEATING & COOLING
Installation, Start-Up and Service Instructions
CONTENTS
Page
SAFETY CONSIDERATIONS.1
General .1
Job Data .1
RECEIVING AND INSTALLATION. 1-10
Step 1 — Check Equipment .1
• IDENTIFY MACHINE
• INSPECT SHIPMENT
Step 2 - Provide Unit Support.4
• ROOF CURB
• SLAB MOUNT
Step 3 — Provide Clearances .4
Step 4 - Rig and Place Unit.4
Step 5 — Connect Condensate Drain. 5
Step 6 — Install Venting .6
Step 7 - Install Gas Piping. 6
Step 8 - Install Duct Connections.7
Step 9 — Install Electrical Connections.8
• HIGH VOLTAGE CONNECTIONS
• SPECIAL PROCEDURES FOR 208-V
OPERATION
• CONTROL VOLTAGE CONNECTIONS
• HEAT ANTICIPATOR SETTING
• TRANSFORMER CIRCUIT PROTECTION
PRE-START-UP . 1 0 , 1 1
START-UP . 1 1 - 20
MAINTENANCE . 2 0-26
NOTE TO INSTALLER — Before the installation, READ
THESE INSTRUCTIONS CAREFULLY AND COM¬
PLETELY. Also, make sure the User’s Manual and Re¬
placement Guide are left with the unit after installation.
SAFETY CONSIDERATIONS
Installation and servicing of air conditioning equipment
can be hazardous due to system pressure and electrical com¬
ponents. Only trained and qualified personnel should in¬
stall, repair or service air conditioning equipment.
Untrained personnel can perform basic maintenance func¬
tions 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.
Fig. 1 - Model 48NLT, NMT, NET, NHT and NVT
A WARNING
Before performing service or maintenance operations
on unit, turn off unit main power switch. Electrical shock
could cause personal injury.
General - The 48NLT, NMT, net, NHT and NVT
units are fully self-contained, combination gas heating/
cooling units designed for outdoor installation. See Fig. 1.
The units are shipped in a vertical configuration and may
be installed either on a rooftop or converted to horizontal
configuration when placed on a ground-level cement slab.
Job Data — Necessary information consists of:
machine location drawings, piping drawings, field wiring
diagrams and rigging guide.
RECEIVING AND INSTALLATION
Step 1 — Check Equipment
IDENTIFY MACHINE — The machine model number and
serial number are stamped on machine identification plate.
Check this information against shipping papers and job data.
INSPECT SHIPMENT — Inspect for shipping damage while
machine is still on shipping pallet. If machine appears to be
damaged or is torn loose from its anchorage, have it exam¬
ined by transportation inspectors before removal. Forward
claim papers directly to transportation company. Manufac¬
turer is not responsible for any damage incurred in transit.
Check all items against shipping list. Immediately notify
the nearest Carrier Air Conditioning office if any item is
missing.
To prevent loss or damage, leave all parts in original pack¬
ages until installation.
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obiigations.
BookM 1 4 PC 111 Catalog No 564-920 Printed in U.S.A. Form 48NT-20SI Pg 1 11-91 Replaces: 48NT-19SI
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Carrier 48NLT Specifications

General

Brand	Carrier
Model	48NLT
Category	Air Handlers
Language	English

Summary

Receiving and Installation

Check Equipment

Inspect machine for shipping damage and verify model/serial numbers.

Provide Unit Support

Install proper unit support (roof curb or slab).

Provide Clearances

Rig and Place Unit

Connect Condensate Drain

Install Venting

Install Gas Piping

Install Duct Connections

Install Electrical Connections

Make safe and compliant field electrical connections.

Start-Up

Refrigerant Leak Check

Locate and repair any refrigerant leaks.

Heating System Start-Up

Verify and adjust heating section operation.

Cooling System Start-Up

Verify and adjust cooling section operation.