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Johnson Controls G770BGJ, Installation Sheets Manual, Page: 14 / 16

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Johnson Controls G770BGJ Installation Sheets Manual Download Page 14

14    G—G770BGJ 100% Lockout, Microprocessor-Based Intermittent Pilot Ignition Control

!

 CAUTION:

Label all wires prior to disconnection when servicing
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.

Repairs and
Replacement

Summary of Contents for G770BGJ

Page 1: ...l 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 con...

Page 2: ...m 24 VAC Ambient Operating and Storage Temperature 40 to 80 C 40 to 176 F Humidity Rating 95 RH non condensing Types of Gas Natural Liquefied Petroleum LP manufactured mixed or LP gas air mix Packaging Bulk pack supplied to original equipment manufacturer individual pack optional Bulk Pack Quantity 50 Bulk Pack Weight 16 kg 33 lb Agency Listings IAS AGA CGA Certificate Number C2154002 Specificatio...

Page 3: ...lication Engineering Department The following definitions describe operating conditions Prepurge Initial time delay between thermostat contact closure and activation of the spark circuit and pilot valve Trial for Ignition Total time pilot valve and spark circuit energize in an attempt to light the pilot Run Main valve energizes and spark turns off after pilot flame is proven Main burner remains on...

Page 4: ... thermostat calling for heat within 10 seconds of proving the main valve will be de energized and the pilot valve will remain energized The control will immediately begin a 30 second trial for ignition During the first second of the trial the spark will remain energized regardless of the presence of flame During the remaining up to 29 seconds of the trial the control will act in the normal manner ...

Page 5: ...tat call for heat Flame present for 30 seconds Lockout End Prepurge Trial for ignition Flame sensed Run Flameout Number of trials maximum allowed Sixteenth flameout Interpurge Lockout End Yes No Yes No No Yes No Yes No Thermostat calling for heat Yes No Yes Figure 2 G770BGJ Sequence of Operation ...

Page 6: ...l is installed in an area that is exposed to water dripping spraying rain etc it must be protected If the control has been exposed to water in any way do not use it WARNING Shock Hazard Avoid electrical shock and equipment damage Disconnect electrical power and turn off gas before wiring control into circuit Location Mounting CAUTION Equipment Damage Hazard Do not mount control where it will be ex...

Page 7: ...t be in continuous contact with a metal surface Use standoff insulators Ensure that the flame sensor wire and high voltage spark transformer cable are separated from one another by a minimum distance of 6 35 mm 1 4 in and not wrapped around any pipe other wiring or accessories Check the voltage rating marked on the control and make sure it is suited to the application Use an NEC Class 2 transforme...

Page 8: ...strike any part of the pilot burner The spark gap is factory set at 2 54 mm 0 10 in nominal Mount the assembly securely to the mounting surface using metal screws WARNING Fire Explosion Hazard Avoid personal injury or property damage by making sure the control functions properly and there are no gas leaks Follow this checkout and startup procedure before leaving the installation WARNING Fire or Ex...

Page 9: ...on Due to variations in wiring and valve options it is advisable to measure the actual current draw of the heating system at the thermostat location Open the thermostat contacts and connect an AC ammeter across the terminals A clamp on meter with a ten turn multiplier can also be used Remember to divide the reading by ten for the actual current value See Figure 4 for meter connections Set the ther...

Page 10: ...The control automatically energizes the system and could cause personal injury or property damage Is LED off If so the control is not receiving power or it has detected a fault Faults are flame present for more than 30 seconds at call for heat more than 16 flameouts a defective control There are three potential system failure conditions no spark and system does not work spark present but pilot doe...

Page 11: ... w as in lockout Causes include flam eout or an internal fault Is spark present now Replace gas valve Did pilot remain lit from previous cycle Turn off supply voltage Is spark cable securely connected to ignition control Is spark cable brittle burnt or cracked Is spark electrode ceram ic cracked Replace pilot burner Replace cable Is spark gap per m anufacturer s specifications and located in pilot...

Page 12: ...ground Yes No No Replace control Yes Is inlet gas pressure per manufacturer s specifications Correct gas pressure No Yes Gas at pilot burner No M ake sure pilot line is not obstructed Check for clean orifice Yes If OK replace pilot valve No Correct or replace pilot burner Is spark gap per m anufacturer s specifications and located in pilot stream Yes Shield from drafts End Figure 6 Spark Present b...

Page 13: ...ut Does sensor cable lack continuity or good insulation Replace cable If system still fails clean pilot assem bly with steel wool or replace flam e sensor orifice or control End M ake sure sensor cable and spark cable are separated and not wrapped around any pipes or accessories Does spark stay on after pilot lights Is gas inlet pressure per m anufacturer s specifications Correct Correct Correct R...

Page 14: ...e 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 Repairs and Replacement ...

Page 15: ...G G770BGJ 100 Lockout Microprocessor Based Intermittent Pilot Ignition Control 15 Notes ...

Page 16: ...G G770BGJ 100 Lockout Microprocessor Based Intermittent Pilot Ignition Control Notes Controls Group FAN 121 507 E Michigan Street Installation Sheets Manual P O Box 423 Printed in U S A Milwaukee WI 53201 ...

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