G779 Universal Intermittent Pilot Ignition Control

Transcription

1 Installation Sheets Manual 121 Gas Combustion Combination Controls and Systems G Technical Bulletin G779 Issue Date 0997 G779 Universal Intermittent Pilot Ignition Control Figure 1: G779 Universal Intermittent Pilot Ignition Control Application The G779 Universal Intermittent Pilot Ignition Control replaces many existing intermittent pilot ignition controls made by various manufacturers. It is a safety control designed for indirect burner ignition and supervision, for use with all gases and applicable to gas-fired appliances with a maximum firing rate of 400,000 Btu/hr. All applications must use redundant valves and must not be subjected to temperatures below -40 F (-40 C) or above 160 F (71 C). The G779 provides precise timing functions, draft-tolerant burner supervision, ignition retries, and a choice of separate or integral spark/sense. For a complete listing of specifications, please refer to Table Johnson Controls, Inc. 1 Part , Rev. A Code. LIT

2 Table 1: Specifications Specification Rating Operating Voltage Operating Current 0.2A Contact Rating (PV and MV) Operating Temperature Humidity Rating Ignition Source Prepurge Number of Trials Before 100% Shutoff Trial Time for Ignition Recycle Delay Period Recommended Spark Gap Means of Flame Detection Flame Failure Response Time Minimum Flame Current Required 24 VAC at 50/60 Hz 2A Continuous 5A Inrush -40 to 160 F (-40 to 71 C) 95% maximum operating temperature non-condensing High voltage spark, capacitive discharge Less than 1 second One 25 seconds* 5 minutes* inch maximum Flame rectification 0.8 second 0.15 microamperes Wiring Connections Spark: Spike Control: 1/4 inch male spade Type of Gas Natural, Liquefied Petroleum (LP), manufactured, mixed, or LP gas-air mix Agency Listings AGA, CGA *Timings increase by 20% under 50 Hz operation. 2 G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control

3 Replacing Existing Ignition Control! CAUTION: Unsafe Operation Hazard. Make sure the control being replaced is in Table 2 or matches the specifications of the G779 precisely. Improper application or replacement of the control could cause unsafe operation. The G779 replaces existing intermittent pilot ignition controls listed in Table 2 or controls with the following specifications: flame detection using flame rectification technology (ability of a flame to conduct and rectify current) integral or remote flame sensing non-100% lockout, 100% lockout, or 100% shutoff with continuous recycle trial for ignition period greater than or equal to 25 seconds prepurge period less than or equal to 4 seconds pilot burners with flow rates of 1500 Btu/hr or less operating with or without vent dampers The G779 is not designed to replace ignition controls with the following specifications: pilot flame detection by any means other than flame rectification trial for ignition period of less than 25 seconds prepurge period greater than 4 seconds standing pilot applications Table 2 lists those controls that are replaceable with the G779 Universal Intermittent Pilot Ignition Control. G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control 3

4 Table 2: Controls That Can Be Replaced By G779 Universal Company Part Number Wiring Figure Camstat IPI Fenwal Fenwal Hamilton Standard Hamilton Standard Honeywell S86A Honeywell S86A Honeywell S86A Honeywell S86A Honeywell S86B Honeywell S86B Honeywell S86B Honeywell S86C Honeywell S86C Honeywell S86C Honeywell S86C Honeywell S86C Honeywell S86D Honeywell S86D Honeywell S86E or 4 Honeywell S86E or 4 Honeywell S86E or 4 Honeywell S86E or 4 Honeywell S86E or 4 Honeywell S86E or 4 Honeywell S86E or 4 Honeywell S86E or 4 Honeywell S86E or 4 Honeywell S86E or 4 Honeywell S86E or 4 Honeywell S86F or 4 Honeywell S86F or 4 Honeywell S86F or 4 Honeywell S86F or 4 Honeywell S86F or 4 Honeywell S86F or 4 Honeywell S86F or 4 Honeywell S86F or 4 Honeywell S86F or 4 Honeywell S86G or 4 Honeywell S86G or 4 Continued on next page... 4 G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control

5 Company (Cont.) Part Number Wiring Figure Honeywell S86G or 4 Honeywell S86G or 4 Honeywell S86G or 4 Honeywell S86H or 4 Honeywell S86H or 4 Honeywell S86H or 4 Honeywell S86H or 4 Honeywell S86H or 4 Honeywell S86H or 4 Honeywell S86H or 4 Honeywell S86H or 4 Honeywell S90A or 6 Honeywell S90B or 6 Honeywell S90B or 6 Honeywell S8600A or 6 Honeywell S8600B or 6 Honeywell S8600C or 6 Honeywell S8600F or 4 Honeywell S8600F or 4 Honeywell S8600F or 4 Honeywell S8600H or 4 Honeywell S8600H or 4 Honeywell S8600H or 4 Honeywell S8600H or 4 Honeywell S8600H or 4 Honeywell S8600H or 4 Honeywell S8600H or 4 Honeywell S8600H or 4 Honeywell S8600H or 4 Honeywell S8600M or 4 Honeywell S8600M or 4 Honeywell S8610A or 6 Honeywell S8610B or 6 Honeywell S8610B or 6 Honeywell S8610C or 6 Honeywell S8610F or 4 Honeywell S8610F or 4 Honeywell S8610F or 4 Honeywell S8610F or 4 Honeywell S8610H or 4 Honeywell S8610H or 4 Continued on next page... G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control 5

6 Company (Cont.) Part Number Wiring Figure Honeywell S8610H or 4 Honeywell S8610H or 4 Honeywell S8610H or 4 Honeywell S8610M or 4 Honeywell S8610M or 4 Honeywell S8610U1003 3, 4, 5, or 6 Honeywell S8620H or 4 Honeywell S8620H or 4 Johnson Controls CSA35A-617R 6 Johnson Controls CSA35A-618R 6 Johnson Controls CSA42A-600R 6 Johnson Controls CSA42A-601R 6 Johnson Controls CSA42A-602R 6 Johnson Controls CSA42A-603R 6 Johnson Controls CSA42A-604R 6 Johnson Controls CSA43A-600R 6 Johnson Controls CSA44A-600R 5 or 6 Johnson Controls CSA45A-601R 5 or 6 Johnson Controls CSA45A-602R 5 or 6 Johnson Controls CSA46A-600R 5 or 6 Johnson Controls CSA48A-600R 5 or 6 Johnson Controls CSA49A-600R 5 or 6 Johnson Controls CSA49A-605R 5 or 6 Johnson Controls CSA51A-601R 5 or 6 Johnson Controls CSA52A-600R 5 or 6 Johnson Controls G60AAA-1 6 Johnson Controls G60AAG-1,2,3,4,5,6,7 6 Johnson Controls G60CAA-1,3 6 Johnson Controls G60CAG-1 through 9 6 Johnson Controls G60CBA-1,2,3 6 Johnson Controls G60CBG-1 through 17 6 Johnson Controls G60CCA-1 6 Johnson Controls G60CCG-1 6 Johnson Controls G60CPG-1 6 Johnson Controls G60DBG-1 6 Johnson Controls G60DCG-1,2,3,4 6 Johnson Controls G60PAG-1,2,3,4,5,6 6 Johnson Controls G60PAJ-1 5 or 6 Johnson Controls G60PAK-1,2 5 or 6 Johnson Controls G60PFH-1,2 6 Johnson Controls G60PFL-1 5 or 6 Johnson Controls G60PVL-1 5 or 6 Continued on next page... 6 G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control

7 Company (Cont.) Part Number Wiring Figure Johnson Controls G60QAG-1,2,3,4 6 Johnson Controls G60QAK-1 5 or 6 Johnson Controls G60QBG-1 through 9 6 Johnson Controls G60QBH-1 6 Johnson Controls G60QBK-1,2,3 5 or 6 Johnson Controls G60QBL-1,2 5 or 6 Johnson Controls G60QCG-1 6 Johnson Controls G60QCJ-1 5 or 6 Johnson Controls G60QCL-1 5 or 6 Johnson Controls G60QDG-1 6 Johnson Controls G60QFL-1 5 or 6 Johnson Controls G60QGH-1 6 Johnson Controls G60QHL-1,2 5 or 6 Johnson Controls G60QJL-1 5 or 6 Johnson Controls G60QLG-1 6 Johnson Controls G60QLK-1 5 or 6 Johnson Controls G60QPL-1 5 or 6 Johnson Controls G60QRH-1,2,3 6 Johnson Controls G60QRL-1,2,3 5 or 6 Johnson Controls G60QSL-1 5 or 6 Johnson Controls G60QTH-1 6 Johnson Controls G60QTL-1 5 or 6 Johnson Controls G60RAG-1 6 Johnson Controls G60RBG-1,2,3 6 Johnson Controls G60RBK-1,2 5 or 6 Johnson Controls G60RCG-1,2 6 Johnson Controls G60RCJ-1 5 or 6 Johnson Controls G60RDG-1 6 Johnson Controls G60RDK-1 5 or 6 Johnson Controls G60RGL-1 5 or 6 Johnson Controls G60RHL-1 5 or 6 Johnson Controls G60RHP-1 5 or 6 Johnson Controls G60RPL-1 5 or 6 Johnson Controls G60RSL-1 5 or 6 Johnson Controls G60TTL-1 5 or 6 Johnson Controls G60ZAG-1,2 6 Johnson Controls G65BBG-1 through 8 5 or 6 Johnson Controls G65BBM-1,2,3,4 5 or 6 Johnson Controls G65BCG-1 5 or 6 Johnson Controls G65BCM-1 5 or 6 Johnson Controls G65BFG-1 5 or 6 Johnson Controls G65BKG-1,2,3 5 or 6 Continued on next page... G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control 7

8 Company (Cont.) Part Number Wiring Figure Johnson Controls G65BKM-1,2,3 5 or 6 Johnson Controls G65BLG-1,2 5 or 6 Johnson Controls G65DBM-1,2,3 5 or 6 Johnson Controls G65DCM-1 5 or 6 Johnson Controls G65DFM-1 5 or 6 Johnson Controls G65DKM-1 5 or 6 Johnson Controls G65DLM-1 5 or 6 Johnson Controls G66AG-1,2 5 or 6 Johnson Controls G66BG-1 5 or 6 Johnson Controls G66MG-1,2 5 or 6 Johnson Controls G66NG-1 5 or 6 Johnson Controls G67AG-3,4,7,8,9,10,11 6 Johnson Controls G67BG-2,3,4,5 6 Johnson Controls G67MG-1,2,3 6 Johnson Controls G67NG-2,4 6 Johnson Controls G600AX-1,2,3 5 or 6 Johnson Controls G600AY-1 6 Johnson Controls G600LX-1,2 5 or 6 Johnson Controls G600LY-1 6 Johnson Controls G600MX-1 5 or 6 Johnson Controls G600NX-1 5 or 6 Johnson Controls G600RX-1 5 or 6 Johnson Controls G670AW-1, 2 6 Johnson Controls G770LGA-1,2 6 Johnson Controls G770LGC-1,2,3,4 6 Johnson Controls G770LHA-1,2 5 or 6 Johnson Controls G770LHC-1 5 or 6 Johnson Controls G770MGA-1,2,3 6 Johnson Controls G770MGC-1,2,3,4,5,6 6 Johnson Controls G770MHA-1,2 5 or 6 Johnson Controls G770MHC-1 5 or 6 Johnson Controls G770NGA-1 6 Johnson Controls G770NGC-4,5,6,7 6 Johnson Controls G770NHA-1 5 or 6 Johnson Controls G770RGA-1 6 Johnson Controls G770RHA-1,2 5 or 6 Johnson Controls G775RGA-1 6 Johnson Controls G775RHA-1,2 5 or 6 Johnson Controls Y79ABC-1 through 7 5 or 6 Johnson Controls Y79ABD-1,2 5 or 6 Johnson Controls Y79BBA-1,2 5 or 6 Continued on next page... 8 G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control

9 Company (Cont.) Part Number Wiring Figure Robertshaw Robertshaw Robertshaw Robertshaw Robertshaw SP715 6 Robertshaw SP735 6 Robertshaw SP735D 6 Robertshaw SP735L 6 Robertshaw USI1715U 3, 4, 5, or 6 Operating Mode Definitions The following are operating mode definitions: Prepurge--Initial time delay between thermostat contact closure and activation of the spark circuit and pilot valve. Trial for Ignition--Total time pilot valve energized and spark/sense sequence activated in an attempt to light pilot. Control attempts to prove flame within the trial for ignition time. 100% Shutoff--If the control does not prove the presence of pilot burner flame within the trial for ignition, the spark circuit and pilot valve are de-energized. Recycle--If 100% shutoff occurs, the control delays 5 minutes (recycle delay period) and begins another trial for ignition. Run--Main valve is energized and spark turns off after pilot flame is proven. Main valve remains energized until thermostat is satisfied. Lockout--An internal or external fault has caused the control to de-energize the spark circuit and valve relays. The thermostat contacts must be opened for 30 seconds and then closed to begin another trial for ignition. G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control 9

10 Sequence of Operation On a call for heat from the system thermostat, the automatic vent damper (if used) is energized and when fully opened, energizes the ignition control. Once the G779 is energized, the diagnostic LED lights and the control begins its trial for ignition. During the trial for ignition period, the control opens the pilot valve and initiates its spark and sense sequence. Within this trial period, the control sparks for 3 seconds, then senses for pilot flame for 1 second, and repeats until the pilot flame is proven or until the trial time expires, whichever occurs first. Upon ignition of pilot gas, the resulting pilot flame will be detected by a flame sensor (separate spark/sense) or by the igniter (integral spark/sense). If the pilot flame is detected within the trial for ignition period, the spark is discontinued, and the main valve is energized. The control remains in this run condition until the thermostat is satisfied or until the flame is lost as described below. The control continuously monitors the pilot flame during the run condition. The LED is off when thermostat is not calling for heat. The main valve will not be energized until the pilot flame is proven. If the pilot flame is not proven within the trial for ignition period, the control enters the 100% shutoff mode. The spark and sense sequence ends, the pilot valve is de-energized, and the control begins the recycle delay period. The LED will flash during the recycle delay period. Upon completion of the delay period, another trial for ignition begins. The control will repeat this sequence of trial-delay-recycle until pilot flame is proven or until the thermostat call for heat ends. If, during the run state, the pilot flame is lost with the thermostat calling for heat, the main valve is de-energized and the spark/sense sequence is re-initiated within 0.8 second. The pilot valve remains energized and the spark/sense sequence continues until flame is detected or until the trial for ignition period expires. Should the control cycle in this manner, where pilot flame is established and then lost, after 16 cycles the control will lockout. The thermostat contacts must be closed for 30 seconds and re-opened before the control will begin another trial. 10 G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control

11 Installation and Wiring Mounting the G779 This bulletin is intended as a guide for qualified service personnel installing or servicing Johnson Controls ignition controls. Carefully follow all instructions in this sheet and all instructions on the appliance. Limit repairs, adjustments, and servicing to the operations listed in this bulletin or on the appliance. Check the voltage rating marked on the control and make sure it is suited to the application. Use a National Electrical Code (NEC) Class 2 transformer, such as a Johnson Controls Y65, to provide 24 VAC under maximum load (electrical ratings are in the Table 1: Specifications). A transformer with excessive primary impedance due to poor coupling affects ignition potential.! WARNING: Fire or Explosion Hazard. If the control 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. Disconnect wires and remove the old control. Mount the G779 in the same location as the old control or choose a location with the shortest direct cable route to the igniter. Use. 8 machine screws or. 6 sheet metal screws through the mounting holes in the enclosure. If the G779 is replacing a control that originally covered the coils of a gas valve (i.e., G60 series), then the new coil cover must be used. Mount the new coil cover in the same position as the original ignition control. Re-use the thread forming screws to fasten it snugly to the valve plate. Use. 6 sheet metal screws to securely fasten the G779 to the new coil cover. G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control 11

12 Modifying Existing Ignition Cable The spark connection on the G779 Universal Control is a barbed spike. When replacing a control using thick, rubber-insulated high-voltage lead wire with a Rajah or 1/4 inch female connection, the crimp-on connector must be cut off. Slide the rubber boot up the cable and cut the lead just above the connector. Make a straight cut perpendicular to the cable and push the lead over the spike in the spark transformer (see Figure 2). Make certain the lead is inserted all the way into the spark transformer. Slide the boot back down the cable and over the spark transformer. High Voltage Cable Insulating Boot Crimp-on Connector Cut off connector here. hvcable.drw Figure 2: High Voltage Cable with Crimp-On Connector If the existing spark cable s insulation is too thin and is terminated with a 1/4 inch female spade connector, use the adapter in the accessories packet. Insert the male spade connection of the adapter into the female connection of the spark cable. Push the rubber-insulated end of the adapter over the barbed spike connection on the G779. Wiring! WARNING: Shock Hazard. Disconnect power supply before modifying wiring to prevent electrical shock or equipment damage. All wiring should be in accordance with the National Electrical Code and all other local codes and regulations. The high-voltage spark cable must not be in continuous contact with a metal surface. Use standoff insulators. Be certain the flame sensor wire and the high-voltage spark cable are separated from one another by a minimum of 1/4 inch, and not wrapped around any pipe, other wiring, or accessories. Use existing wires wherever possible. If the original control used a wiring harness, the connector must be cut off. Strip the wires and crimp 1/4 inch female terminals (included in the accessories packet) onto the wires. The schematics in Figures 3 through 6 show typical wiring hookups for the G779 when using separate spark/sense with or without a vent damper and integral spark/sense with or without a vent damper. Use the information provided in Table 2 to select the correct wiring schematic. 12 G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control

13 Vent Damper System Pilot Burner Assembly Integral Igniter/Sensor Main Burner Ground Pilot Gas Supply GROUND PLUG 5 24 V LED THS 2 Vent Damper Wiring Harness Transformer PV 1 MV 3 SENSE 4 G779 Ignition Control INTEGRAL P.V. M.V. Leave jumper in place. Thermostat Limits in Thermostat Line Only g7791.drw Power Supply Figure 3: Wiring for Integral Spark/Sense with Vent Damper Pilot Burner Assembly Integral Igniter/Sensor Main Burner Ground Pilot Gas Supply GROUND PLUG 5 24 V LED THS 2 Transformer PV 1 INTEGRAL P.V. M.V. MV 3 SENSE 4 G779 Ignition Control Leave jumper in place. Thermostat Limits in Thermostat Line Only Power Supply Figure 4: Wiring for Integral Spark/Sense without Vent Damper G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control 13

14 Pilot Burner Assembly Flame Sensor Vent Damper System Main Burner Ground Pilot Gas Supply GROUND PLUG 5 Vent Damper Wiring Harness Transformer 24 V LED THS 2 PV 1 INTEGRAL MV 3 SENSE 4 P.V. M.V. Thermostat Power Supply G779 Ignition Control Limits in Thermostat Line Only Figure 5: Wiring for Separate Spark/Sense with Vent Damper Pilot Burner Assembly Flame Sensor Main Burner Ground Pilot Gas Supply GROUND PLUG 5 24 V LED THS 2 Transformer PV 1 INTEGRAL MV 3 SENSE 4 P.V. M.V. Thermostat Power Supply G779 Ignition Control Limits in Thermostat Line Only Figure 6: Wiring for Separate Spark/Sense without Vent Damper 14 G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control

15 Checkout and Startup Procedures! WARNINGS: Fire or 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. Fire or Explosion Hazard. Do not attempt to check out this system by manually lighting the pilot. This could energize the main valve. Make sure all components function properly by performing the following shutoff test: 1. With the gas and thermostat off, turn on power to the appliance. 2. Turn the thermostat to a high setting and verify that the control goes through the operating sequence to a shutoff condition. te: 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. 6. Turn the thermostat to a high setting and verify successful ignition and a normal run condition for at least 3 minutes. 7. Do a leak check on all pipe joints downstream of the gas valve. 8. Turn the thermostat down for at least 30 seconds and then back up again. Verify successful ignition at least three times before leaving the installation. Troubleshooting Procedures Preliminary Checks If the system does not function properly, determine the cause using the procedures in this section. Before proceeding with troubleshooting the system, check the following: Are all mechanical and electrical connections tight? Is system wired correctly? Is gas inlet pressure per manufacturer s specifications? Is system powered? Is thermostat calling for heat? G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control 15

16 Flash Codes The G779 control features a diagnostic LED. The LED displays the status of the control. If the LED is constantly off, then the control is not receiving power, or it has detected a fault. A defective control or more than 16 flameouts will be indicated as a fault. If the LED is flashing steadily, then the control is in its recycle period. If the LED is constantly on, then the control is in its normal operation (refer to Table 3). Table 3: Flash Code Reference Flash Code Off Constantly Steady Flashing (1/2 second on, 2 1/2 seconds off) On Constantly Flash Code Description power or detected fault In recycle period rmal operation! WARNING: Fire or Explosion Hazard. Do not attempt servicing or troubleshooting when the LED is flashing (recycle mode). The control automatically energizes the system and could cause personal injury or property damage. Failure Conditions and Corrective Action There are three potential system failure conditions: spark and system does will not work. Spark is present but pilot will not light. Pilot lights but main burner does not come on. Determine the failure condition, then use the respective flowcharts on the following pages to troubleshoot the system. Perform the procedures in the Checkout and Startup Procedures section after any servicing. Repairs and Replacement! CAUTION: Label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. 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 wholesaler. 16 G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control

17 Start 24 VAC present between THS 2 and ground? Check for defective transformer, thermostat, or faulty wiring. Open thermostat contacts for 30 seconds and then close. Is spark present now? System was in lockout. Causes include flameout or an internal fault. Did pilot remain lit from previous cycle? Replace gas valve. Turn off supply voltage. Is spark cable securely connected to ignition control? Correct Is spark cable brittle, burnt, or cracked? Replace cable. Is spark electrode ceramic cracked? Replace pilot burner. Is spark gap per manufacturer's specifications and located in pilot gas stream? Correct or replace pilot burner. Replace control. End Figure 7: Spark and System will not Work G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control 17

18 Start Pilot valve connections correct and secure? Connect pilot valve securely between Terminal 1 and ground. 24 VAC between Terminal 1 and ground? Replace control. Is inlet gas pressure per manufacturer's specifications? Correct gas pressure. Gas at pilot burner? Make sure pilot line is not obstructed. Check for clean orifice. Correct or replace pilot burner. Is spark gap per manufacturer's specifications and located in pilot stream? If OK, replace pilot valve. Shield from drafts. End Figure 8: Spark is Present but Pilot will not Light 18 G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control

19 Start Does spark stay on after pilot lights? 24 VAC between Terminal 3 and ground? Replace control. Make sure sensor cable and spark cable are separated and not wrapped around any pipes or accessories. Is gas inlet pressure per manufacturer's specifications? Correct Correct Is sensor cable securely connected to SENSE 4 and flame sensor? Is main valve wiring securely connected to M.V. 3 and ground? Correct Replace flame sensor. Is sensor ceramic cracked? Replace main valve. Correct Is sensor cable grounded out? Does sensor cable lack continuity or good insulation? Replace cable. If system still fails, clean pilot assembly with steel wool, or replace flame sensor, orifice, or control. End Figure 9: Pilot Lights but Main Burner does not Come On G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control 19

20 tes Controls Group FAN E. Michigan Street Installation Sheets Manual P.O. Box 423 Printed in U.S.A. Milwaukee, WI G Gas Combustion Combination Controls and Systems G779 Universal Intermittent Pilot Ignition Control