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G77x Intermittent Pilot Ignition Controls
The G77x family of controls is designed for indirect ignition of natural
Description
gas, Liquefied Petroleum (LP) gas, manufactured gas, mixed gas, or
LP gas-air mixtures.
Following are the application requirements of the G77x control.
Application
Requirements
• The G77x can be used on gas-fired equipment with a maximum firing
• All G77x applications must use a redundant gas valve system where
© 2000 Johnson Controls, Inc.
Part No. 24-8143-588, Rev. A
Code No. LIT-121250
All manuals and user guides at all-guides.com
Gas Combustion Combination Controls and Systems G
Figure 1: G77x Intermittent Pilot Ignition Controls
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.
the pilot and main valve seats are in series and opened in sequence for
intermittent pilot ignition.
Installation Sheets Manual 121
Technical Bulletin G77x
Issue Date 0600
www.johnsoncontrols.com
1
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Table of Contents
Related Manuals for Johnson Controls G776
Summarization of Contents
Product Description and Application
Description
Overview of the G77x family of controls designed for indirect ignition of various gas types.
Application Requirements
Details on the requirements for using the G77x control, including firing rate limits and valve system specifications.
Operational Details
Operating Mode Definitions
Definitions of various operating conditions and states for the G77x ignition controls.
Sequence of Operation
Illustrates the step-by-step process the G77x control follows during a call for heat and ignition.
Installation and Wiring
Location and Mounting
Guidance on proper placement and mounting of the control unit for optimal performance and safety.
Electrical Connections
Details on connecting the ignition control wiring, including precautions for safe and correct installation.
Component Functions and Mounting
Rollout Switch Function
Explains the function and impact of the rollout switch on the G77x ignition control's operation.
Pilot Burner/Igniter-Sensor
Instructions for installing, positioning, and mounting the pilot burner/igniter-sensor assembly.
Checkout, Startup, and Replacement
Checkout and Startup Procedure
Procedure for verifying proper operation and safety before leaving the installation.
Thermostat Heat Anticipator Settings
Guidance on setting the thermostat heat anticipator to match system current draw for efficiency.
Replacement Procedure
Step-by-step instructions for replacing an existing intermittent pilot ignition control.
Modifying Existing Ignition Cable
Steps for adapting existing ignition cables to connect with the new G77x control's spike transformer connection.
Service Checkout Procedures
Troubleshooting guide for diagnosing and resolving system malfunctions.
Repairs and Replacement
Information that G77x controls are not field repairable and must be replaced with factory-recommended units.
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