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Service Handbook
COMMERCIAL GAS WATER HEATERS
MODELS (A)BCG385T500-8N
& (A)BCG38T500-8P
INSTALLATION CONSIDERA SERIES 120/121 TIONS - PRE SERVICE
CHECKS - WATER HEATER CONSTRUCTION -
OPERATION & SERVICE - TROUBLESHOOTING
INSTALLATION CONSIDERATIONS - PRE SERVICE
P.O. Box 1597
Johnson City, TN 37605 CHECKS - OPERATION & SERVICE -TROUBLESHOOTING
SERVICING SHOULD ONLY BE PERFORMED BY A QUALIFIED SERVICE AGENT.
PRINTED IN THE U.S.A 0510 318664-000
1
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COMMERCIAL GAS WATER HEATER SERVICE MANUAL TABLE OF CONTENTS INTRODUCTION ............................................................3 Gas Control Valve/Burner Area View ......................18 Qualifications ...........................................................3 Blower Prover Switch - Settings .............................19 Service Warning........................................................3 Thermostat and Ignition control Board View ...........20 Service Reminder ..............
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INTRODUCTION INTRODUCTION This Service Manual is designed to be an aid in servicing and troubleshooting American models (A)BCG385T500-8N/8P Series 120/121 commercial water heaters. The instructions and illustrations contained in this service manual will provide you with troubleshooting procedures to verify proper operation and to diagnose and repair common service problems. This Service Manual does not replace or supersede the instruction manual that came with the water heater. Always refe
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REQUIREMENTS REQUIREMENTS INSTRUCTION MANUAL Have a copy of the instruction manual that came with the water heater on hand for the model being serviced. Instruction manuals can be obtained at the American Water Heaters web site (www.americanwaterheater.com) or by calling technical support at 800-456-9805. Installation information given in this service manual is not a complete installation instruction. Installation information covered in this service manual has a limited focus as it applies
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INSTALLATION CONSIDERATIONS INSTALLATION CONSIDERATIONS Installation information given in this service manual IS NOT a complete installation instruction. Installation information covered in this service manual has a limited focus as it applies to servicing. This service manual does not replace or supersede the Instruction Manual that came with the water heater. Always refer to the instruction manual that came with the water heater for complete installation instructions. If the instruction ma
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INSTALLATION CONSIDERATIONS Table 1 NATURAL GAS PROPANE (LP) GAS ‡ Maximum Supply Gas Pressure 10” W.C. (2.49 kPa) 12” W.C. (2.99 kPa) † 5.2” W.C. (1.29 kPa) 11” W.C. (2.74 kPa) Minimum Supply Gas Pressure * Manifold Gas Pressure 3.5” W.C. (0.87 kPa) 10” W.C. (2.49 kPa) ‡ Maximum supply pressure; readings are taken while gas is not fl owing (static pressure) AND while gas is fl owing (dynamic pressure). Supply pressure must never exceed this maximum value. † Minimum supply gas pressure; readin
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INSTALLATION CONSIDERATIONS Insufficient Make-up Air, Negative Air Pressure, and Downdrafts A lack of combustion and ventilation air can create a negative ambient air pressure in the installed space. The vent system on one or more gas fired appliances can experience down drafts due to the outdoor air pressure being greater than the ambient air pressure in the installed space. Where multiple gas fired appliances are installed, one or more gas fired appliances can “pull air” through the vent s
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INSTALLATION CONSIDERATIONS Make-up Air: Direct Communication with Outdoors A fresh supply of make-up air for combustion can be supplied to the water heater through make-up air ducts, which directly communicate with the outdoors. (Not Direct Vent.) Two openings are required: one within 12 inches of the top of the enclosure and one within 12 inches of the bottom of the enclosure. Each opening must have a free area of not less than 1 square inch per 4,000 BTUH of the total input of all applian
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INSTALLATION CONSIDERATIONS Contaminated Air Carefully review the warnings concerning contaminated combustion and ventilation air in the instruction manual that came with the water heater. Combustion air that is contaminated can greatly diminish the life span of the water heater and water heater components such as burners, igniters, flue baffles and vent system components. Propellants of aerosol sprays, beauty shop supplies, water softener chemicals and chemicals used in dry cleaning process
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INSTALLATION CONSIDERATIONS Table 2 MINIMUM CLEARANCES TO COMBUSTIBLE SURFACES “A” - Right Side “B” - Left Side “C” - Back 5” (12.7 cm) 5” (12.7 cm) 5” (12.7 cm) A, B, and C clearances to non-combustible surfaces is “0” inches. A 20” clearance to cover remains unchanged. CLEARANCES (EXTERIOR) The illustration below shows the required clearances for venting units using natural draft venting. The vent must extend at least 3 feet above the highest point where it passes through a roof of a buil
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INSTALLATION CONSIDERATIONS VENTING The (A)BCG385T500-8N/8P water heater is classified by ANSI as a Category I (non- condensing, negative pressure venting) appliance. It is approved for type B vent. The blower (draft inducer) does not pressurize the exhaust. NOTE: This section of the service manual is not a complete venting installation instruction. Refer to the instruction manual that came with the water heater; ensure the venting has been installed per all instruction manual requirements.
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OPERATION AND SERVICE OPERATION AND SERVICE SEQUENCE OF OPERATION 1. Call for heat is activated when temperature sensed from Thermistor Probes falls below the Thermostat setting. 2. Blower (Draft Inducer) is energized. 3. Ignition Control Board verifies that the Blower Prover Switch is closed and that the Blower (Draft Inducer) is operating. 4. Igniter is energized. 5. Gas Valve is energized and burners ignite 6. Ignition Control Board verifies flame at burners. 7. Water is
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OPERATION AND SERVICE ELECTRICAL SEQUENCE 1. Switch Power on to unit. 2. Thermostat calls for heat. 3. Ignition Control Board performs diagnostic check on system components. 4. On completion of diagnostics check, the Ignition Control Board energizes the Blower (Draft Inducer). 5. The Blower (Draft Inducer) begins drawing air through appliance, closing the Blower Prover Switch. 6. On completion of Blower Prover Switch engagement, the Ignition Control Board begins the ignition cycle. 7.
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PSI IN ON OFF PSI IN ON OFF OPERATION AND SERVICE WIRING DIAGRAM R BK INDUCER BK R UPPER PROBE/ BLOWER PROVER ECO PRESSURE SWITCH W BK Y THERMOSTAT R TO EARTH R GROUND BL BR IGNITION BOARD R 1a 1 1b BK R W HOT 120 VAC NEUTRAL EARTH GROUND LOWER PROBE G NOTE: Must be properly grounded IGNITER/FLAME and have correct polarity SENSOR connections. R R 120 VAC CIRCUIT FACTORY INSTALLED BY INSTALLER W BK - BLACK WIRING DIAGRAM FOR (A)BCG385T500-8N/8P BR - BROWN WHEN EQUIPPED WITH WHITE-RODGERS IGNI
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OPERATION AND SERVICE OPERATING SEQUENCE - FLOW CHART Power On Call for Heat Control Locks Out - LED Self diagnostic check is performed Displays 2, 6, or 8 (Correct state of Blower Prover Switch and ECO is verified) NO Flash Error Code (polarity, earth ground , and Igniter presence are verified ) (See Error Code Chart ) YES Blower (Draft Inducer) Motor is Energized Control Locks Out Blower Prover Switch (N.O.) Contacts NO Displays 3 Flash Close at – 2.85“ W.C. ± 0.13” W.C. Error Code YES Ign
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OPERATION AND SERVICE GAS CONTROL VALVE This gas valve is a 24 volt AC combination-step opening valve. It includes two valves assembled in parallel, connected by a wiring harness. Note that the valves have fixed pressure regulation and are not adjustable. However, the manifold (outlet) pressure is adjustable as described on the next page. IMPORTANT: • For complete device shut-off, both gas control knobs must be in the OFF position. • Both gas control knobs must be in the same position fo
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OPERATION AND SERVICE Manifold Pressure Adjustment The main gas regulators are found beneath the silver or black cap screws. (Natural Gas valves have silver caps; Propane valves have a black caps). Remove the caps to access the outlet (manifold) pressure adjustment screw. IMPORTANT: Ensure that the outlet pressure matches the manifold pressure that is listed on the water heater rating plate. • Natural Gas valves are factory preset to 3.5 inches W.C. The full rate outlet pressure range
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OPERATION AND SERVICE GAS CONTROL VALVE/BURNER AREA VIEW Honeywell Gas Valve Rollout Shield Main Burner Shield Radiation Shield Main Burner with Hot Surface Igniter (HSI) mounted Figure 14 Table 3 HOT SURFACE IGNITER (HSI) Volts AC Nominal 80 VAC Ohms Resistance 11.0 - 20.0 @ 77° F (25° C) NOTICE FLAME ROD CROSSES PATH OF FLAME 0.1” to 0.25”. Servicing should only be performed by a Qualifi ed Service Agent 18
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OPERATION AND SERVICE BLOWER PROVER SWITCH - SETTINGS Vent Connection Exhaust/Outlet Blower Prover Switch Optional Hot Water Outlet Blower (Draft Inducer) Figure 15 Table 4 BLOWER PROVER SWITCH TABLE Model Pressure Setting to Close Switch (Inches W.C.) (A)BCG385T500-8N/8P -2.85” ± 0.13” NOTE: The Blower Prover Switch contacts are normally open and will close on a fall in pressure. This will be a negative pressure (i.e., a vacuum). Servicing should only be performed by a Qualifi ed Service Ag
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OPERATION AND SERVICE THERMOSTAT AND IGNITION CONTROL BOARD VIEW Figure 16 Servicing should only be performed by a Qualifi ed Service Agent 20
