Johnson Controls G775 - User Manual

Installation Sheets Manual 121
Gas Combustion Combination Controls and Systems G
Technical Bulletin G77x
Issue Date 0600
© 2000 Johnson Controls, Inc.
1
Part No. 24-8143-588, Rev. A www.johnsoncontrols.com
Code No. LIT-121250
Figure 1: G77x Intermittent Pilot Ignition Controls
The G77x family of controls is designed for indirect ignition of natural
gas, Liquefied Petroleum (LP) gas, manufactured gas, mixed gas, or
LP gas-air mixtures.
Following are the application requirements of the G77x control.
• The G77x can be used on gas-fired equipment with a maximum firing
rate of 117 kW (400,000 Btu/hr). Any application over 117 kW
(400,000 Btu/hr) must have written approval in advance from the
Johnson Controls Heating Products Engineering Department.
• All G77x applications must use a redundant gas valve system where
the pilot and main valve seats are in series and opened in sequence for
intermittent pilot ignition.
G77x Intermittent Pilot Ignition Controls
Description
Application
Requirements
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Johnson Controls G775 Specifications

General

Brand	Johnson Controls
Model	G775
Category	Controller
Language	English

Summary

Description

Application Requirements

Operating Mode Definitions

Sequence of Operation

Installation and Wiring

Location and Mounting

Guidance on selecting an optimal location and mounting method for the ignition control.

Electrical Connections

Rollout Switch Function

Pilot Burner;Igniter-Sensor Setup

Pilot Burner;Igniter-Sensor Location;Mounting

Guidelines for positioning and securely mounting the pilot burner/igniter-sensor assembly.

Checkout and Startup Procedure

Thermostat Heat Anticipator Settings

Replacement Procedure

Modifying Ignition Cable Connections

Service Checkout and Troubleshooting

Preliminary Checks

Initial steps to verify system power, wiring, gas pressure, and thermostat operation.

Failure Conditions and Corrective Action

Identifies common system failures and outlines steps for diagnosis and repair.