Table of Contents
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Service Handbook
COMMERCIAL GAS WATER HEATERS
FOR MODELS:
BTN 120 thru 400(A) Series 100 - 108
BTR 151 & 201 Series 100 & 101
INSTALLATION CONSIDERATIONS - PRE SERVICE CHECKS -
500 Tennessee Waltz Parkway
CONSTRUCTION - OPERATION & SERVICE - TROUBLESHOOTING
Ashland City, TN 37015
SERVICING SHOULD ONLY BE PERFORMED BY A QUALIFIED SERVICE TECHNICIAN
PRINTED IN THE U.S.A. 0713
317923-001
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Summary of Contents for A.O. Smith Master-Fit 100 Series
- Page 1 Service Handbook COMMERCIAL GAS WATER HEATERS FOR MODELS: BTN 120 thru 400(A) Series 100 - 108 BTR 151 & 201 Series 100 & 101 INSTALLATION CONSIDERATIONS - PRE SERVICE CHECKS - 500 Tennessee Waltz Parkway CONSTRUCTION - OPERATION & SERVICE - TROUBLESHOOTING Ashland City, TN 37015 SERVICING SHOULD ONLY BE PERFORMED BY A QUALIFIED SERVICE TECHNICIAN PRINTED IN THE U.S.A.
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Page 3: Table Of Contents
TABLE OF CONTENTS INTRODUCTION ..............2 QUALIFICATIONS . -
Page 4: Introduction
INTRODUCTION The service handbook is designed to aid in servicing and troubleshooting A. O. Smith BTN and BTR 151/201 commercial water heaters in the field. No duplication or reproduction of this book may be made without the express written authorization of the A. O. Smith Corporation. The following text and illustrations will provide you with a step by step procedure to verify proper installation, operation, and troubleshooting procedures. -
Page 5: Tools Required
TOOLS REQUIRED • Electrical multimeter capable of measuring continuity/ ohms, ac & dc volts, amperes, microamperes, millivolts, and frequency (hz) • UEi Model DL289 or equivalent • Digital manometer + 60" W. C., resolution 0.01" increments Note: A digital manometer is required for testing pressure switches and can replace a gas pressure gauge, draft gauge or slack tube manometer for checking gas pressure. -
Page 6: Installation Considerations
INSTALLATION CONSIDERATIONS GAS AND ELECTRICAL CHARACTERISTICS Gas Supply Pressure Models Gas Type Manifold/ Volts/Hz Amperes Minimum Maximum Pressure All Models Natural 5.2" W.C. (1.29 kPa) 14.0" W.C. (3.48 kPa) 120/60 120/60 < 5 All models require a minimum gas supply pressure of 5.2” W.C. The minimum supply pressure is measured while gas is flowing (dynamic pressure). - Page 7 AIR SUPPLY: Stoichiometric or theoretical complete combustion requires 10 cubic feet of air per 1,000 BTU of gas supplied. The National Fuel Gas Code also recommends an additional 2.5 cubic feet of “excess” air. For information on minimum make-up air opening sizes for various building installations, refer to the National Fuel Gas Code NFPA 54/ANSI Z223.1.
- Page 8 – 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.
- Page 9 AIR REQUIREMENTS: For safe operation an adequate supply of fresh uncontaminated air for combustion and ventilation must be provided. An insufficient supply of air can cause recirculation of combustion products resulting in contamination that may be hazardous to life. Such a condition often will result in a yellow, luminous burner flame, causing sooting of the combustion chamber, burners and flue tubes and creates a risk of asphyxiation.
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Page 10: Minimum Clearances
MINIMUM CLEARANCES This water heater is approved for installation on combustible flooring in an alcove with minimum clearance from combustion construction as indicated in below Figure and Table. In all installations the minimum combustible clearances from vent piping shall be 6” (15.2 cm). Vent piping passing through a combustible wall or ceiling must be a continuous run (no joints) and retain 6”... -
Page 11: Exterior Clearances
EXTERIOR CLEARANCES 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 building and at least 2 feet higher than any portion of a building within a horizontal distance of 10 feet (for vents of 12 inches in diameter or less). -
Page 12: Gas Valve
GAS VALVE The supply gas pressure is normally measured at the gas valve inlet gas pressure tap, if available, when the gas is flowing. The manifold gas pressure is measured at the manifold pressure tap of the gas valve when the gas is flowing. -
Page 13: Gas Valve
GAS VALVE All BTN and BTR water heaters are classified by ANSI as Category I (non-condensing, negative pressure venting) appliances. They are approved for type B vent. The draft inducer does not pressurize the exhaust. For larger applications BTN and BTR 151, 201 water heaters can be common vented together, either in a tapered manifold or constant size manifold. -
Page 14: Type B Gas Vent
VENTING TABLES FOR CATEGORY 1 TYPE B GAS VENT – Multiple Gas Fired Tank-Type Heaters When venting multiple Category 1 tank type heaters using Type B vent pipe, follow the installation tables below which give sizing and data based upon NFPA 54 ANSI Z223.1. MODEL BTN-120 Total Vent Height (Feet) Input: 120,000 Btu/hr... - Page 15 MODEL BTN-250 Total Vent Height (Feet) Input: 250,000 Btu/hr Vent Connector Size: 6 inches Input Btuh/hr Rise Vent Connector Diameter (Inches) 250,000 1 Ft. 250,000 2 Ft. 250,000 3 Ft. Number of Heaters Combined Input (Btu/hr) Manifold and Common Vent Diameters (Inches) 500,000 750,000 1,000,000...
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Page 16: Draft Proving Pressure Switch - Settings
DRAFT PROVING PRESSURE SWITCH – SETTINGS DRAFT PROVING PRESSURE SWITCH TABLE Pressure Setting BTN Models BTR Models To Close Switch (Inches W.C.) -2.40" ± 0.07" -2.20" ± 0.07" 180, 250 -1.60" ± 0.07" 199C -3.00" ± 0.10" 199, 200 -1.95" ± 0.07" -2.30"... -
Page 17: Thermostat And Ignition Control Board View
THERMOSTAT AND IGNITION CONTROL BOARD VIEW Servicing should only be performed by a Qualified Service Technician... -
Page 18: White Rodgers Integrated Control - Thermostat
WHITE RODGERS INTEGRATED CONTROL – THERMOSTAT Servicing should only be performed by a Qualified Service Technician... -
Page 19: White Rodgers Ignition Control Board
WHITE RODGERS IGNITION CONTROL BOARD Servicing should only be performed by a Qualified Service Technician... -
Page 20: Gas Control Valve/ Burner Area View
GAS CONTROL VALVE/ BURNER AREA VIEW Servicing should only be performed by a Qualified Service Technician... -
Page 21: Btn/ Btr 151, 201 - Electrical Sequence
BTN/ BTR 151, 201 – ELECTRICAL SEQUENCE The following information will describe the Sequence of Operation for this water heater: 1. Switch power on to unit. 2. Thermostat calls for heat. 3. Ignition Control Board performs diagnostic check on system components. 4. -
Page 22: Operating Sequence - Flow Chart
OPERATING SEQUENCE – FLOW CHART Servicing should only be performed by a Qualified Service Technician... -
Page 23: Heater Control Board Diagnostic Led Interpretation And Troubleshooting
HEATER CONTROL BOARD DIAGNOSTIC LED INTERPRETATION AND TROUBLESHOOTING TEST 1 - 120 VAC CHECK TO HEATER: • No Green display "Power" LED On. • Plugs are in receptacles. • Supply power breaker is not “open”. • On/Off heater switch is “On”. 120 VAC check to water heater ON/OFF switch. -
Page 24: Ignition Control Board Diagnostic Led Interpretation And Troubleshooting
IGNITION CONTROL BOARD DIAGNOSTIC LED INTERPRETATION AND TROUBLESHOOTING CONDITIONS: • Power On. • Red, heater control “Call for Heat” LED – on. • Red, ignition control board diagnostic LED – Flashing. • Note LED Flash Code before resetting heater. LED Status Indication 1 Flash System is in lock out. -
Page 25: Test 2 - Polarity Check
TEST 2 - POLARITY CHECK CONDITIONS: • No Green display "Power" LED On. • Plugs are in receptacles. • Supply power breaker is not “open”. • On/Off heater switch is “On”. 120 VAC check to water heater ON/OFF switch. TEST 1 Check for 115-125 VAC black wire to ground\ 115 VAC check to E13 Terminal and 2B receptacle. -
Page 26: Test 3 - Continuity Check Of High Limit (Eco)
TEST 3 CONTINUITY CHECK OF HIGH LIMIT (ECO) – CONDITIONS: • Power On – No Hot Water. • Red, heater control “Call for Heat” LED – On. • Red ignition control board diagnostic LED – 4 Flashing. • Note LED Flash Code before resetting water heater control. •... -
Page 27: Test 4 - Upper Temperature Probe Continuity Check
TEST 4 UPPER TEMPERATURE PROBE CONTINUITY CHECK – CONDITIONS: • Power On – Water below temperature set point. • Red, water heater control “Reset Status” LED – OFF. • "Call for Heat" LED Off. OHMS RESISTANCE TABLE ° F OHMS 70°... -
Page 28: Test 5 - Calling For Heat - No Inducer Operation
TEST 5 CALLING FOR HEAT NO INDUCER OPERATION – – CONDITIONS: • Power On – No Hot Water. • Plugs in Receptacles. • Red "Call for Heat" LED-ON. • Inducer "Off". "call for heat" LED indicator "Diagnostic LED indicator" IF..THEN.... -
Page 29: Test 6 - Inducer On - No Ignition
TEST 6 INDUCER ON NO IGNITION – – CONDITIONS: • Power On. • Plugs in Receptacles. • Inducer operating. • No power to Hot Surface Igniter (HSI) Note LED flash code. TEST 6 24 VAC Check of Blower Prover/Low Gas Pressure Circuit IF.. -
Page 30: Operation
TEST 7 INDUCER ON PROVER SWITCH AND LOW GAS SWITCH CLOSED. – – NO IGNITER OPERATION CONDITIONS: • Power On. • Plugs in Receptacles. • Inducer ON. • 24V at ignition board E1, Pin 10. • No power to Igniter. TEST 7 Voltage check and continuity check of hot surface igniter circuit... -
Page 31: Test 8 - Igniter Heats - No Main Burner
TEST 8 IGNITER HEATS NO MAIN BURNER – – TEST 8 IGNITOR HEATS..NO MAIN BURNER IF..THEN.... Short heat up time of igniter. Check control box grounding. Normal (Approximate 20 seconds) Check for 24V from E1, Pin 12 to ground during 4 second trial. warm up - no ignition. -
Page 32: Test 9 - Igniter Heats - No Main Burner
TEST 9 IGNITER HEATS NO MAIN BURNER – – CONDITIONS: • Test 8 completed then: • Turn off power. • Disconnect wires from gas valve. TEST 9 IGNITER HEATS – NO MAIN BURNER IF..THEN.... Meter reads 0 or 1. •... - Page 33 TEST 10 MAIN BURNER IGNITION FOR LESS THAN 5 SECONDS – CONDITIONS: • Power On – plug connected. • Main Burner ignites for approximately 5 seconds then goes out. • Tests 8 and 9 completed. • Note flash code on ignition board LED. TEST 10 MAIN BURNER IGNITION FOR LESS THAN 5 SECONDS IF..
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Page 34: Test 11 - Water Heater Shutting Off Below Setting
TEST 11 WATER HEATER SHUTTING OFF BELOW SETTING – CONDITIONS: • Main burner ignited. • Stored water is below temperature setting more than 5° F (Tank Average). • Power Off. • Plug disconnected from heater control board receptacle E3 and E4. WATER HEATER SHUTTING OFF BELOW SETTING TEST 11 (Water Temperature Circuit Check - Continuity) -
Page 35: Display Lights On Integrated Heater Control
DISPLAY LIGHTS ON INTEGRATED HEATER CONTROL INDICATION ACTION STATUS Calling for heat Normal status. No action required. • Check for excessively hot water (203° F or higher). The ECO (Energy Cut-Out) has opened. • Check the resistance of the temperature probes and continuity of the high limit (ECO). -
Page 36: Wiring Diagram
WIRING DIAGRAM Servicing should only be performed by a Qualified Service Technician... -
Page 37: Notes
NOTES Servicing should only be performed by a Qualified Service Technician... -
Page 38: Notes
NOTES Servicing should only be performed by a Qualified Service Technician... -
Page 39: Notes
NOTES Servicing should only be performed by a Qualified Service Technician... - Page 40 COMMERCIAL GAS WATER HEATERS Visit the "Information Central" link of www.hotwater.com for a listing of available Service Handbooks. For additional information contact: A. O. Smith Corporation 500 Tennessee Waltz Parkway Ashland City, TN 37015 1-800-527-1953 www.hotwater.com ©2013 A. O. Smith Corporation 317293-001...
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