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G770BGJ 100% Lockout, Microprocessor-Based
Description
© 1998 Johnson Controls, Inc.
Part No. 24-8143-596, Rev.
Code No. LIT-121253
Intermittent Pilot Ignition Control
Figure 1: G770BGJ 100% Lockout,
Microprocessor-Based IPI Control
The G770BGJ is a member of the G700 series ignition control family.
This Intermittent Pilot Ignition (IPI) control is microprocessor-based and
provides two additional trials if the supervised pilot flame is not proven
within the initial trial for ignition period. A diagnostic LED (Light-
Emitting Diode) indicates operating status and assists in system
troubleshooting.
The microprocessor provides improved reliability and performance. All
function timings are independent of voltage and temperature variations.
The control is monitored on a cycle-by-cycle basis for maximum
operational integrity.
Installation Sheets Manual 121
Gas Combustion Combination Controls and Systems G
Technical Bulletin G770
Issue Date 0498
1
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Summary of Contents for Johnson Controls G770BGJ
- Page 1 Intermittent Pilot Ignition Control Figure 1: G770BGJ 100% Lockout, Microprocessor-Based IPI Control The G770BGJ is a member of the G700 series ignition control family. Description This Intermittent Pilot Ignition (IPI) control is microprocessor-based and provides two additional trials if the supervised pilot flame is not proven within the initial trial for ignition period.
- Page 2 The performance specifications are nominal and conform to acceptable industry standards. For application at conditions beyond these specifications, consult the local Johnson Controls office. Johnson Controls, Inc. shall not be liable for damages resulting from misapplication or misuse of its products.
- Page 3 The G770BGJ ignition control is designed to ignite gas at the pilot burner Application through the use of a spark. An electrode is positioned in the pilot gas stream and adjusted to provide a nominal spark gap of 2.54 mm (0.10 in.).
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Page 4: Sequence Of Operation
Sequence of Operation The G770BGJ Intermittent Pilot Ignition Control is energized on a call for heat from the system thermostat. The control will wait 0.6 second and then energize the LED and begin the trial for ignition. Prepurge will not occur before the first trial. - Page 5 ? Thermostat Flameout? calling for heat? Number of trials = maximum allowed? Sixteenth Interpurge flameout? Lockout E n d Figure 2: G770BGJ Sequence of Operation G—G770BGJ 100% Lockout, Microprocessor-Based Intermittent Pilot Ignition Control 5...
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Page 6: Installation And Wiring
Choose a location that provides the shortest, direct cable route to the spark electrode, pilot burner/igniter-sensor assembly. Easy access to the terminals is desired for wiring and servicing. The G770BGJ may be mounted in any position. Mount the control on a grounded metal surface with No. - Page 7 T ransform e r Therm ostat T herm ostat G 770B G J Line O nly Ignition C ontrol P ilo t Valve M ain V alve Figure 3: Connection Diagram G—G770BGJ 100% Lockout, Microprocessor-Based Intermittent Pilot Ignition Control 7...
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Page 8: Start-Up Procedure
Note: The burner will not light because the gas is off. 3. Turn off the thermostat. 4. Turn on the gas and purge gas lines of all air. 5. Check for gas leaks with a soap solution. 8 G—G770BGJ 100% Lockout, Microprocessor-Based Intermittent Pilot Ignition Control... - Page 9 C la m p -o n A m m e te r (D ivid e re a d in g b y te n .) Figure 4: Current Measurement for Thermostat Heat Anticipator G—G770BGJ 100% Lockout, Microprocessor-Based Intermittent Pilot Ignition Control 9...
- Page 10 Determine the failure condition, then use the respective flowchart on the following pages to troubleshoot the system. Perform the procedures in the Checkout and Startup Procedure section after any servicing. 10 G—G770BGJ 100% Lockout, Microprocessor-Based Intermittent Pilot Ignition Control...
- Page 11 ? Y e s R e p la ce E n d co n tro l. Figure 5: No Spark, and System Does Not Work G—G770BGJ 100% Lockout, Microprocessor-Based Intermittent Pilot Ignition Control 11...
- Page 12 ? Ye s S h ie ld fro m d ra fts. E n d Figure 6: Spark Present, but Pilot Does Not Light 12 G—G770BGJ 100% Lockout, Microprocessor-Based Intermittent Pilot Ignition Control...
- Page 13 , o r co n tro l. E n d Figure 7: Pilot Lights, but Main Valve Does Not Come On G—G770BGJ 100% Lockout, Microprocessor-Based Intermittent Pilot Ignition Control 13...
- Page 14 Replacement controls. Wiring errors can cause improper and dangerous operation. The G770BGJ control is not field repairable. Do not attempt field repairs. Use only an exact or factory-recommended replacement control. All other accessories, such as flame sensors, electrode assemblies, pilot assemblies, and leads can be obtained through the original equipment manufacturer or Johnson Controls distributor.
- Page 15 Notes G—G770BGJ 100% Lockout, Microprocessor-Based Intermittent Pilot Ignition Control 15...
- Page 16 Notes Controls Group FAN 121 507 E. Michigan Street Installation Sheets Manual P.O. Box 423 Printed in U.S.A. Milwaukee, WI 53201 16 G—G770BGJ 100% Lockout, Microprocessor-Based Intermittent Pilot Ignition Control...