valent VXE Series User Manual

Document 483593
Model VX / VXE
Dedicated Outdoor Air Unit
Dedicated Outdoor Air Unit 1
Installation, Operation and Maintenance Manual
Please read and save these instructions for future reference. Read carefully before attempting to assemble, install,
operate or maintain the product described. Protect yourself and others by observing all safety information. Failure
to comply with these instructions will result in voiding of the product warranty and may result in personal injury
and/or property damage.
General Safety Information
WARNING
The roof lining contains high voltage wiring. To
prevent electrocution, do not puncture the interior or
exterior panels of the roof.
DANGER
• Always disconnect power before working on or near
this equipment. Lock and tag the disconnect switch
or breaker to prevent accidental power up.
• If this unit is equipped with optional gas accessories,
turn off gas supply whenever power is disconnected.
CAUTION
This unit is equipped with a compressed refrigerant
system. If a leak in the system should occur,
immediately evacuate the area. An EPA Certified
Technician must be engaged to make repairs or
corrections. Refrigerant leaks may also cause bodily
harm.
CAUTION
When servicing the unit, the internal components may
be hot enough to cause pain or injury. Allow time for
cooling before servicing.
Only qualified personnel should install and maintain this
system. Personnel should have a clear understanding of
these instructions and should be aware of general safety
precautions. Improper installation can result in electric
shock, possible injury due to coming in contact with
moving parts, as well as other potential hazards. Other
considerations may be required if high winds or seismic
activity are present. If more information is needed,
contact a licensed professional engineer before moving
forward.
1. Follow all local electrical and safety codes, as well
as the National Electrical Code (NEC), the National
Fire Protection Agency (NFPA), where applicable.
Follow the Canadian Electrical Code (CEC) in
Canada.
2. All moving parts must be free to rotate without
striking or rubbing any stationary objects.
3. Unit must be securely and adequately grounded.
4. Do not spin wheel faster than maximum cataloged
fan RPM. Adjustments to fan speed significantly
affect motor load. If the fan RPM is changed, the
motor current should be checked to make sure it is
not exceeding the motor nameplate amps.
5. Verify that the power source is compatible with the
equipment.
6. Never open access doors to the unit while it is
running.

valent VXE Series Specifications

General

Brand	valent
Model	VXE Series
Category	Air Handlers
Language	English

Summary

General Safety Information and Warnings

Safety Warnings and Precautions

Includes DANGER, WARNING, and CAUTION statements for safe operation and maintenance.

Subassemblies Description

Electrical and Gas Supply Entry

Recommended Entry Locations

Electrical Information and Wiring

High Voltage Wiring Warning

Cautionary note about high voltage wiring within the unit's roof lining.

Power Disconnection and Safety

Instruction to lock out disconnects before performing any work.

Wiring and Code Compliance

Emphasis on following NEC, CEC, and local electrical codes.

Grounding and Bonding Requirements

Requirement for proper unit grounding and conduit protection.

High Voltage Work Safety

Caution that high voltage work requires a qualified electrician.

Control Center Components

Main Control Center Overview

Component Operation

Phase Monitor Function

Explains the phase monitor's role in detecting faults.

Variable Frequency Drive (VFD) Operation

Describes VFD control for blower speed and input options.

Supply Fan VFD Sequence Options

Details modulation based on CO2, static pressure, or building pressure.

Exhaust Fan VFD Sequence Options

Explains exhaust fan modulation based on building pressure or damper position.

OA and Recirculation Damper Sequence

Describes damper control based on CO2 or building pressure.

Factory-Installed Refrigeration System Components

Packaged DX Cooling System Schematic

Packaged DX Components List

Factory-Installed Refrigeration System Components (Continued)

Air-Source Heat Pump System Schematic

Air-Source Heat Pump Components List

Start-Up Unit Procedures

Start-Up Safety Precautions

Includes DANGER, CAUTION, and WARNING statements for start-up.

Start-Up Checklist and Data Recording

Information required for comprehensive unit start-up.

Pre-Start-Up Checklist

General Unit Checks

Checks for fasteners, wheels, filters, and dampers.

Electrical System Checks

Verification of power, wiring, and controls.

Compressor Pre-Start-Up Checks

Procedures for compressor pre-start-up requirements.

Start-Up Procedure Steps

Sequence of actions to initiate unit operation.

Start-Up Checklist - General

Motor Amp Draw Recording

Section to record amp draw for various fans.

Fan RPM and Rotation Verification

Checks for correct fan rotation direction and RPM.

Start-Up Checklist - Packaged Direct Expansion (DQX)

DX Unit Compressor Cooling Parameters

Recording values for superheat, subcooling, pressure, and temperature.

Start-Up Checklist - Air-Source Heat Pump (ASHP)

ASHP Unit Compressor Cooling Parameters

Recording cooling mode parameters for ASHP compressors.

ASHP Unit Compressor Heating Parameters

Recording heating mode parameters for ASHP compressors.

Start-Up Components

Fan Inspection and Setup

Checking fan for free rotation, damage, and proper offset.

Fan Wheel Rotation Direction

Procedure to verify correct fan wheel rotation.

Supply/Exhaust Fan VFD Setup

Notes on VFD setup and motor nameplate verification.

Vibration Causes and Solutions

Identifying and addressing sources of excessive vibration.

Discharge Air Temperature Sensor Installation

Guidance on installing the discharge air temperature sensor.

Start-Up Components (Continued)

Airflow Monitoring Setup and Calibration

Instructions for setting up and calibrating the airflow monitor.

Optional Dirty Filter Switch Adjustment

Procedure for adjusting the dirty filter switch.

Communication Setup for Airflow Monitor

Steps for configuring communication parameters (MODBUS).

Hot Gas Bypass Valve Adjustment

Instructions for adjusting the hot gas bypass valve setting.

Optional Energy Wheel Operation

Energy Wheel Start-Up Procedures

Energy Wheel Sequence of Operation

Optional Energy Wheel Maintenance

Inspection and Cleaning Procedures

Reassembly and Belt Inspection

Optional Energy Wheel Troubleshooting

Energy Wheel Operational Issues

Microprocessor Controller Alarms

VFD Alarms and Reset Procedures

Digital Scroll Compressor Controller Faults

Troubleshooting – Unit

Blower Fails to Operate

Diagnosing issues with blower operation, motor starters, and overload.

Motor Over Amps Diagnosis

Troubleshooting causes for motor overcurrent.

Low Airflow (CFM) Diagnosis

Diagnosing issues related to low airflow from the fan.

High Airflow (CFM) Diagnosis

Troubleshooting causes for excessive fan airflow.

Excessive Noise or Vibration

Identifying and resolving sources of unit noise and vibration.

Troubleshooting – Refrigeration Circuit

Compressor Will Not Run or Start

Diagnosing issues preventing compressor startup.

Compressor Cuts Out on Low Pressure

Troubleshooting low pressure cutouts.

Low Pressure Switch Cutout Issues

Diagnosing issues with the low pressure switch.

Troubleshooting – Refrigeration Circuit (Continued)

Compressor Cuts Out on High Pressure

Diagnosing issues related to high pressure cutouts.

Excessive Load on Evaporator Coil

Troubleshooting high suction pressure due to evaporator load.

Low Discharge Pressure Issues

Troubleshooting causes of low discharge pressure.

Compressor Thermal Overload Trips

Troubleshooting compressor thermal overload trips.

High Suction Pressure Issues

Diagnosing and resolving high suction pressure conditions.

Compressor Short Cycling Diagnosis

Diagnosing and resolving compressor short cycling.

Compressor Hums, Will Not Start

Diagnosing startup issues where compressor hums but doesn't run.

High Discharge Pressure Issues

Troubleshooting causes of high discharge pressure.

Compressor Oil Loss Diagnosis

Troubleshooting oil loss from the compressor.

Compressor Noise or Vibration Issues

Identifying causes of compressor noise and vibration.

Low Suction Pressure Issues

Diagnosing and resolving low suction pressure conditions.

Insufficient Capacity or Performance

Addressing issues of reduced unit capacity or performance.

Liquid Line Frosting or Wetness

Diagnosing causes of a frosted or wet liquid line.

Suction Line Frosting Diagnosis

Troubleshooting suction line frosting.

Evaporating Coil Frosting

Identifying normal vs. abnormal frost on the evaporating coil.

Routine Maintenance

Maintenance Frequency Guidelines

Monthly Maintenance Tasks

Semiannual Maintenance Tasks

Annual Maintenance Tasks

Routine Maintenance Procedures

Lubrication Procedures

Damper Maintenance Procedures

Fan Motor Maintenance

Fan Wheel and Fastener Maintenance

Coil Maintenance Procedures

Internal Filter Maintenance

External Filter Maintenance

Unison Air Handler Start-Up Form

Exterior Air Handler Inspection

Check for shipping damage, caulking, access doors, and ductwork connections.

Interior Air Handler Inspection

Split Air Handler Inspection

Control Cabinet Inspection

Power Inspection

Dampers Inspection

Blowers and Blower Motors Inspection

VFD Parameters Recording

Indirect Fired Gas Furnace Inspection

IDF Furnace Performance Readings

Electric Heater Inspection

Integral AC System Inspection

Heat Pump Operation and Readings

Water Coil Inspection

Energy Recovery Wheel Inspection

DDC Controller Inspection

DDC Mode of Operation Testing

DDC Parameters Recording