Carrier 50EJQ - User Manual

Installation, Start-Up and
Service Instructions
CONTENTS
Page
SAFETY CONSIDERATIONS ................ 1
INSTALLATION ............................ 1-20
Step 1 — Provide Unit Support ............. 1
• ROOF CURB
• ALTERNATE UNIT SUPPORT
Step 2 — Rig and Place Unit ............... 5
• POSITIONING
• ROOF MOUNT
Step 3 — Field Fabricate Ductwork ......... 5
Step 4 — Make Unit Duct Connections ...... 5
Step5—TrapCondensate Drain ........... 7
Step 6 — Controls Options ................. 7
• FEATURES WITH THERMOSTAT CONTROL
OF UNIT
• FEATURES WITH SENSOR CONTROL OF
UNIT (Stand-Alone Applications)
• FEATURES WITH SENSOR CONTROL OF
UNIT (Network Applications)
Step 7 — Make Electrical Connections ...... 9
• POWER WIRING
• FIELD POWER SUPPLY
• FIELD CONTROL WIRING
Step 8 — Make Outdoor-Air Inlet
Adjustments .............................. 14
• ECONOMIZER
• ECONOMIZER SETTINGS
Step 9 — Position Power Exhaust/
Barometric Relief Damper Hood ........... 18
Step 10 — Install Accessories .............. 18
START-UP ................................21-28
SERVICE ..................................29-33
TROUBLESHOOTING ......................34-38
START-UP CHECKLIST ...............CL-1, CL-2
SAFETY CONSIDERATIONS
Installation and servicing of air-conditioning equipment
can be hazardous due to system pressure and electrical com-
ponents. Only trained and qualified service personnel should
install, repair, or service air-conditioning equipment.
Untrained personnel can perform basic maintenance func-
tions of cleaning coils and filters and replacing filters. All
other operations should be performed by trained service per-
sonnel. When working on air-conditioning equipment, ob-
serve 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 ex-
tinguishers available for all brazing operations.
Before performing service or maintenance operations on
unit, turn off main power switch to unit. Electrical shock
could cause personal injury.
INSTALLATION
Step 1 — Provide Unit Support
All panels must be in place when rigging. Unit is not
designed for handling by fork truck.
ROOF CURB — Assemble and install accessory roof curb
in accordance with instructions shipped with the curb.
Accessory roof curb and information required to field fab-
ricate a roof curb or horizontal adapter are shown in Fig. 1.
Install insulation, cant strips, roofing, and counter flashing
as shown. Ductwork can be secured to roof curb before unit
is set in place.
IMPORTANT: The gasketing of the unit to the roof
curb is critical for a leak-proof seal. Install gasket sup-
plied with the roof curb as shown in Fig. 1. Improp-
erly applied gasket can result in air leaks and poor unit
performance.
Curb should be level. This is necessary to permit unit drain
to function properly. Unit leveling tolerance is shown in
Fig 1. Refer to Accessory Roof Curb Installation Instruc-
tions for additional information as required. When acces-
sory roof curb is used, unit may be installed on class A, B,
or C roof covering material.
ALTERNATE UNIT SUPPORT — When the curb or adapter
cannot be used, support unit with sleepers using unit curb or
adapter support area. If sleepers cannot be used, support long
sides of unit (refer to Fig. 2 and 3) with a minimum number
of equally spaced 4-in. x 4-in. pads. 50EJQ,EWQ024 and
028 units require 3 pads on each side. Unit may sag if sup-
ported by corners only.
50EJQ,EWQ024,028
Single-Package Rooftop
Heat Pump Units
Manufacturer reserves the right to discontinue, or change at any time, specifications or designs without notice and without incurring obligations.
Book 1
Tab 5a
PC 111 Catalog No. 535-002 Printed in U.S.A. Form 50EJQ,EWQ-2SI Pg 1 8-97 Replaces: 50EJQ,EWQ-1SI

Summary

SAFETY CONSIDERATIONS

INSTALLATION

Unit Support and Placement

Instructions for securing the unit to a roof curb or alternative support structure.

Ductwork and Drain Connections

Steps for fabricating, connecting ductwork, and trapping condensate drains.

Controls and Electrical Connections

Overview of control options, thermostat/sensor integration, and electrical wiring.

Outdoor Air Inlet Adjustments

Procedures for adjusting economizer and outdoor air inlet settings.

START-UP

Unit Preparation and Component Checks

Checks for unit readiness, valves, wiring, and basic components.

System Operation and Cycles

Describes unit operation modes, economizer, sequence of operation, and defrost cycle functions.

Power Exhaust and Economizer Setup

Details on power exhaust operation and economizer adjustments.

SERVICE

Component Access and Cleaning

Guidance on accessing components and cleaning internal/external parts like coils and filters.

Lubrication and Fan Maintenance

Procedures for lubricating bearings and adjusting fan performance/motors.

TROUBLESHOOTING

Refrigerant Circuiting Diagrams

Visual guides illustrating refrigerant flow for heating and cooling cycles.

Control Board Diagnostics

Explanation of control board LEDs and alarm codes for troubleshooting.

START-UP CHECKLIST

Pre-Start-Up Verification

Checklist items for verifying unit installation and pre-operation readiness.

Start-Up Measurements

Procedures for recording electrical, temperature, and pressure readings during start-up.

Carrier 50EJQ Specifications

General

Model Number	50EJQ
Category	Heat Pump
HSPF Rating	Up to 9.0
Refrigerant	R-410A
Voltage	208/230V
Stages	Single Stage