Johnson Controls GVD Series - User Manual

5586996-JSG-A-0120
25–50 Tons
Premier Rooftop Units
R-410A
LD26877
Table of Contents
Nomenclature ...................................................................... 4
Pre Start-Up Checklist ......................................................... 7
Start-Up ............................................................................... 9
Long Term Storage ......................................................... 9
Checking System Prior to Initial Start (No Power) ......... 9
Unit Checks (Power Applied) ....................................... 10
Initial Start-Up .............................................................. 16
Refrigerant Charge ............................................... 16
Checking Sub-Cooling and Superheat.................. 16
Leak Checking ...................................................... 17
Gas Heat Models .................................................. 17
Phase Monitor Adjustment .................................... 20
Commissioning Mode................................................... 20
Air Balancing Wizard .................................................... 20
Start-Up Wizard ............................................................ 24
Start-Up Wizard Sequence ................................... 26
Sequences of Operation .................................................... 30
Control Boards ............................................................. 30
Variable Frequency Drives (VFDs) ............................... 37
Unit Type ...................................................................... 38
Occupancy Mode ......................................................... 38
Morning Warm-up/Cool Down ............................... 38
Coast..................................................................... 38
Remote Safety Shutdown ............................................ 39
Low Voltage Monitoring ................................................ 39
Supply Fan Operation .................................................. 39
Supply Fan Alarm.................................................. 39
MZVAV Supply Fan ............................................... 39
SZVAV Supply Fan ............................................... 40
Redundant Supply Fan VFD ................................. 40
Cooling Operation ........................................................ 40
MZVAV Cooling Operation .................................... 40
SZVAV Cooling Operation ..................................... 42
Compressors and Refrigeration Circuits ............... 42
Compressor Staging Sequences .......................... 44
Condenser Systems and Fans.............................. 48
Dehumidication (Hot Gas Reheat) ...................... 49
Economizer ........................................................... 51
Heating ......................................................................... 52
Gas Heating .......................................................... 52
Electric Heating ..................................................... 56
Hydronic Heating .................................................. 56
MZVAV Heating Operation .................................... 56
SZVAV Heating Operation .................................... 57
Ventilation..................................................................... 58
Ventilation Sequences .......................................... 58
Low Mixed Air Temperature Limiting ..................... 58
Demand Control Ventilation .................................. 58
Continuous Ventilation .......................................... 59
Pre-Occupancy Purge........................................... 59
Humidification............................................................... 60
Humidication Sequence ...................................... 60
Exhaust System ........................................................... 60
Modulating Exhaust Fan ....................................... 60
Modulating Exhaust Damper with Fan .................. 60
External Control .................................................... 60
Return Fan ................................................................... 60
Return Fan Discharge Pressure ........................... 61
Supply Fan Airow Tracking.................................. 61
Energy Recovery Wheel .............................................. 61
Single Speed Energy Recovery Wheel ................. 61
Variable Speed Energy Recovery Wheel .............. 61
Ultraviolet Lights........................................................... 61
Smoke Control ............................................................. 62
Purge .................................................................... 62
Pressurization ....................................................... 62
Depressurize ......................................................... 62
START-UP & OPERATION

Johnson Controls GVD Series Specifications

General

Brand	Johnson Controls
Model	GVD Series
Category	Air Conditioner
Language	English

Summary

Nomenclature and Unit Configuration

Unit Type Configurations

Explains the two unit configurations, MZVAV and SZVAV, and their operational differences.

Supply Fan Operation Details

Details the direct drive supply fan control and VFD usage based on unit type.

Pre Start-Up and Initial Checks

General Inspection Checklist

Outlines general inspection items required before unit start-up.

System Checks (No Power)

Steps to check the system for leaks and proper installation before applying power.

Unit Checks (Power Applied)

Procedures for verifying unit operation and parameters after power application.

Start-Up Procedures and Wizards

Initial Start-Up and Refrigerant Verification

Covers initial start-up steps, refrigerant charge, sub-cooling, superheat, and leak checks.

Commissioning and Air Balancing Wizards

Explains commissioning mode and airflow balancing wizard for unit setup.

Start-Up Wizard Process

Guides the technician through automated self-tests for unit configuration.

Sequences of Operation Overview

Control Board Identification

Identifies the standard control boards that are part of the unit's system.

Variable Frequency Drives (VFDs)

Details the application and field parameters for VFDs used in unit operation.

Cooling Operation Modes

Explains how the unit operates in various cooling modes for MZVAV and SZVAV configurations.

Compressors and Refrigeration Circuits

Describes the components and safety features of the unit's refrigeration circuits.