SERVICE HANDBOOK FOR STANDARD RESIDENTIAL HIGH EFFICIENCY ATMOSPHERIC VENT (FVIR) GAS WATER HEATERS MODELS: GAHH 40 100, GP 6 40YPC T 100, PCG6240T403NOV 100, PCG2J4040T3NOV 100, 12 40GPC T 100, PCG2J4040T3NOV 100, GAHH 50 100, GP 6 50YPC T 100, PCG250T403NOV 100, PCG2J5040T3NOV 100, 12 50GPC T 100, PCG2J5040T3NOV 100 Printed in U.S.A.
ALL TECHNICAL AND WARRANTY QUESTIONS SHOULD BE DIRECTED TO THE LOCAL DEALER FROM WHOM THE WATER HEATER WAS PURCHASED. IF YOU ARE UNSUCCESSFUL, CONTACT A. O. SMITH WATER HEATERS RESIDENTIAL TECHNICAL ASSISTANCE AT 1-800-527-1953 OR WWW.HOTWATER.COM.
SERVICE HANDBOOK Your safety and the safety of others is extremely important in the servicing of this water heater. Many safety-related messages and instructions have been provided in this handbook and on the water heater to warn you and others of a potential hazard. Read and obey all safety messages and instructions throughout this handbook. It is very important that the meaning of each safety message is understood by you and others who service this water heater.
Breathing Hazard - Carbon Monoxide Gas Install vent system in accordance with codes. Do not operate water heater if flood damaged Heater should not be installed for High Altitude operation above 10,100 feet (3,078 m). Do not operate if soot buildup. Fire or Explosion Harzard Do not store or use gasoline or other flammable vapors and liquids in the vicinity of this or any other appliance. Avoid all ignition sources if you smell Natural or LP gas. Do not expose water heater control to excessive gas pressure.
TABLE OF CONTENTS INTRODUCTION: Service Handbook Introduction ...........................................................................................................................3 Warnings and Cautions .......................................................................................................................................4 Table Of Contents ...............................................................................................................................................
BASIC INSTALLATION & OPERATION INSTALLATION OF RESIDENTIAL GAS WATER HEATER See Labels and Installation Instructions and Use & Care Guide for clearances. Exhaust Vent to Ouside of Building Union Use Draft Hood supplied with unit Union Untempered Hot Water Gas Supply Cold Water Inlet *Massachusett: Install a vacuum relief in cold water line per section 19 MGL 142. Expansion Tank Pressurize to Equal Supply Water Pressure* (Relieve water pressure on the expansion tank before adjusting air pressure.
COMBUSTION AIR AND VENT SYSTEM REQUIREMENTS Combustion Air Requirements: Table 1: WARNING BTUH Input Carbon Monoxide Warning 30,000 45,000 60,000 75,000 90,000 105,000 120,000 135,000 Water heater must be vented to outdoors. Vent must be installed by a qualified technician using the local and state codes or, in the absence of local and state codes, the National Fuel Gas Code, ANSI Z223.1 (NFPA 54) - current edition, and/or the installation instructions.
COMBUSTION AIR AND VENT SYSTEM REQUIREMENTS All Air from Inside the Building: When additional air is to be provided to the confined area from additional room(s) within the building, the total volume of the room(s) must be of sufficient size to properly provide the necessary amount of fresh air to the water heater and other gas utilization equipment in the area.
COMBUSTION AIR AND VENT SYSTEM REQUIREMENTS Vent Connectors: 1. Type B, Double wall, U.L. Listed Vent Pipe. 2. Single wall Vent Pipe. 1 SQ. INCH PER 2000 BTUH 100 SQ. INCH MINIMUM (EACH) CONFINED SPACE Maintain the manufacturer’s specified minimum clearance from combustible materials when using type B double wall vent pipe. Vent connectors made of type B, double wall vent pipe material may pass through walls or partitions constructed of combustible material if the minimum listed clearance is maintained.
COMBUSTION AIR AND VENT SYSTEM REQUIREMENTS • • • The following figures are examples of vent pipe system installations and may or may not be typical for your specific application. Consult the “National Fuel Gas Code”, NFPA 54, ANSI Z223.1-current edition and the guidelines set forth by prevailing local codes. The connector must be firmly attached and sealed to prevent it from falling out. To aid in removing the connector, a thimble or slip joint may be used.
KNOW THE WATER HEATER’S COMPONENT PARTS Electronic Control Display (Upper Control) The Electronic Control Display panel used on this water heater provides an easy-to-read, eye level display for temperature adjustment, fault code diagnostics and recall, powered anode rod operation and setting the temperature scale for either Fahrenheit (°F) or Celsius (°C). Figure 11.
KNOW THE WATER HEATER’S COMPONENT PARTS Burner/Manifold Door Assembly The burner/manifold door assembly consists of several components such as: main burner, burner orifice, manifold tube and flame sense / hot surface igniter. See figure below for the complete list of components (Figure 13). Figure 13. Main Burner Manifold Tube Manifold Door View Port Scoop side to be placed on the same side as View Port.
KNOW THE WATER HEATER’S COMPONENT PARTS Figure 16. Flammable Vapor Cut Off Switch (FV Sensor) The water heater is equipped with a FV sensor, for detecting the presence of flammable vapors (e.g. spilled gasoline). When the sensor detects those vapors, the heater will shut down and not operate. If flammable vapors are detected or the sensor is inoperative, an icon will flash on the electronic control display and the heater will go into a lockout mode.
WATER HEATER OPERATION The figure below shows the water heater’s sequence of operation when a call for heat is initiated. The gas control valve/thermostat will attempt to light the burner three times. If the flame sense rod in the burner/ manifold assembly does not detect ignition, the control will enter lockout mode indicated by the electronic control display’s flashing of the appropriate status code. SEQUENCE OF OPERATION Call for heat indicated by flashing of display screen status codes.
FILLING, DRAINING AND FLUSHING THE WATER HEATER TANK It is recommended that the tank be drained and flushed every 6 months to remove sediment which may build up during operation. The water heater should be drained if being shut down during freezing temperatures. To drain the tank, perform the following steps: 1. Turn off the gas to the water heater at the manual gas shut-off valve and turn off the electrical power to the gas control/thermostat valve. 2.
LIGHTING INSTRUCTIONS Read and understand these directions thoroughly before attempting to operate the water heater. Make sure the view port is not missing or damaged. Make sure the tank is completely filled with water before operating the water heater. The gas control valve/thermostat has an “On/Off Switch” and needs to be turned on before the water heater is operational. Check the label on the front of the water heater near the gas control valve/thermostat for the correct gas.
ADJUSTING THE TEMPERATURE ON THE ELECTRONIC CONTROL DISPLAY Adjusting the Temperature Set Point - The thermostat of this water heater has been factory set at its lowest position. It is adjustable and must be reset to the desired temperature setting to reduce the risk of scald injury. The electronic control display temperature should be set at approximately 120°F (49°C) and this is the preferred starting point, see Figure 21 Some states have a requirement for a lower setting.
USING THE ELECTRONIC CONTROL DISPLAY How to select or change the temperature scale from Fahrenheit (°F) to Celsius (°C). Figure 22. Gas Control Valve/Thermostat Settings COOLER HOTTER Electronic Control Display 1. The temperature scale defaults to Fahrenheit (°F). 2. To change to Celsius (°C), press the two temperature adjustment buttons at the same time for more than five (5) seconds but less than 10 seconds to enter the Temperature Scale Selection mode.
USING THE ELECTRONIC CONTROL DISPLAY Reviewing Fault Codes: 1. Press the red up arrow button one time. 2. The display will show either E0 or E1. 3. If E0 is shown, there are no faults. By pressing the up arrow button again the display will exit the Field Service mode, or the control will exit automatically after no button is pressed for five (5) seconds. 4. If E1 is shown, the control will flash the icons of the most recent fault. 5.
ELECTRONIC CONTROL DISPLAY TROUBLESHOOTING ELECTRONIC CONTROL DISPLAY Please check guidelines below. For your safety, water heater service should be performed only by a qualified service person. Read the GENERAL SAFETY INFORMATION supplied by the water heater manufacturer. CONTROL DISPLAY STATUS 1. “POWER” Flashing PROBLEM Communication Error The system has detected a communication error between the upper and lower controls. 2. 3.
CONTROL DISPLAY TROUBLESHOOTING CONTROL DISPLAY STATUS 6. “P-SW”, “OPEN”, and “CLEAN SCREEN” Flashing SOLUTION PROBLEM The air pressure switch contacts remain open longer than 11 seconds after the combustion fan is energized. 1. Clean the screen on the combustion air intake chamber. Turn the power “OFF” for 10 to 20 seconds then “ON” again to clear the error code. If the problem persists: 2. Ensure the pressure switch sensing tube is in good condition and securely connected at both ends. 3.
CONTROL DISPLAY TROUBLESHOOTING CONTROL DISPLAY STATUS 9. 10. 11. PROBLEM “FV-SENSE” Flashing (Continued from previous page) “LDO-SW”, “OPEN”, and “CLEAN SCREEN” Flashing “FV-SENSE” and “OPEN” Flashing SOLUTION 4. System must be manually reset by entering a special FVS reset sequence into the Electronic Control Display. See Electronic Control Display - FV - Sense Reset Sequence for instructions. It is also recommended that the FV Sensor be replaced.
TROUBLESHOOTING FLOWCHART APPLY POWER TO APPLIANCE REQUEST FOR HEAT PRESENT? NO 3 MINUTE AUTOMATIC RESET TIME DELAY YES IS PRESSURE SWITCH PROVEN OPEN WITHIN NO 5 SECONDS? WAIT FOR PRESSURE SWITCH TO OPEN DISPLAY ERROR NUMBER 7 YES COMBUSTION FAN ON IS PRESSURE SWITCH PROVEN OPEN WITHIN NO WAIT FOR PRESSURE SWITCH TO OPEN DISPLAY ERROR 5 SECONDS? IS PRESSURE SWITCH PROVEN CLOSED NO WITHIN 11 SECONDS? 7 YES WAIT FOR PRESSURE SWITCH TO CLOSE DISPLAY ERROR NUMBER NUMBER 6 ONE HOUR AUTOMATI
EXTERNAL INSPECTION AND CLEANING Cleaning the Air Intake Chamber Screen: Figure 24. • At least twice annually the air intake chamber screen should be inspected for any dust or debris that may have accumulated on the louvers. NOTE: If the water heater is located in an area that is subjected to lint, pet hair or dirt, it may be necessary to check the air intake chamber screen more frequently. • Use a vacuum cleaner with a hose attachment to remove any dust or debris that may have accumulated on the screen.
ELECTRONIC CONTROL DISPLAY REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Figure 26. Removing the Electronic Control Display: 1. Set the gas control valve/thermostat to its lowest setting by pressing the “COOLER” and “HOTTER” buttons together at the same time holding for 1 second.
POWERED ANODE ROD REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Tools required: Ratchet with 1-1/16” Socket, Pliers, and Teflon® Tape or an approved pipe sealant. Figure 30. Removing the Powered Anode Rod: 1.
Installing the Powered Anode Rod: 8. Use Teflon® tape or an approved pipe sealant on threads of the new powered anode rod. 9. Prior to installing, it will be necessary to use pliers to bend up approximately 90° the electrical male connector on the top of the powered anode rod. The electrical connector should be bent upward in order to allow the 1-1/16” deep well socket to pass over the connector.
PRESSURE SWITCH REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Tools required: Phillips Head Screwdriver. Figure 36. Removing the Pressure Switch: 1. Set the gas control valve/thermostat to its lowest setting by pressing the “COOLER” and “HOTTER” buttons together at the same time holding for 1 second.
TRANSFORMER REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Tools required: Ratchet with 5/16” Socket or 5/16” Nut Driver, Phillips Head Screwdriver. Figure 40. Removing the Transformer: 1.
Installing the New Transformer: 10. Insert the wiring connector that goes to the gas control valve/thermostat through the wire protector on the side of the transformer box (Figure 44). 11. Attach the two (2) flag terminal connectors to the transformer by aligning and pressing down (Figure 44). 12. Position the new transformer inside the transformer box where the wiring connections are nearest their exit points (Figure 44). 13.
AIR INTAKE CHAMBER BOX REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Tools required: Phillips Head Screwdriver. Figure 45. Removing the Air Intake Chamber Box: 1. Set the gas control valve/thermostat to its lowest setting by pressing the “COOLER” and “HOTTER” buttons together at the same time holding for 1 second.
14. Rotate the top of the air intake chamber box from left to right (only a few inches in both directions) while pulling outward at the bottom removing the air intake chamber box from the combustion chamber pipe saving the air intake chamber gasket for reinstallation (Figure 49). 15. Unplug the air pressure tubing from the back of the old air intake chamber box (Figure 50). 16. The wire harness goes through the rubber wire protector in the back of the air intake chamber box (Figure 50). 17.
25. Install the air intake chamber box by rotating the top of the air intake chamber box from left to right (only a few inches in both directions) while pressing on the bottom portion of the air intake chamber box. When properly installed the air intake chamber box will be in place against the water heater’s side aligning with the screw holes. 26. Secure the air intake chamber box to the water heater’s side by reusing the 4 screws removed in step 13 (Figure 53). Figure 53.
WIRING HARNESS REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Figure 57. Tools required: Phillips Head Screwdriver. Removing the Air Intake Chamber Box: 1. Set the gas control valve/thermostat to its lowest setting by pressing the “COOLER” and “HOTTER” buttons together at the same time holding for 1 second.
Replacing the Wiring Harness: 13. Locate the male to female electrical connection with close pin lock on wiring harness (located on the right side of fan) (Figure 62). 14. To separate the electrical connection of the fan and wiring harness: press down on the back portion of the close pin lock of the electrical connection while pulling the connection in the opposite directions. 15. The wire harness goes through the rubber wire protector in the back of the air intake chamber box (Figure 62). 16.
25. Install the air intake chamber screen, ensuring that the prongs of the lower portion of the air intake chamber screen are in place in the holding slots. Using the 2 screws removed in step 8, secure the air intake chamber screen (Figure 65). 26. Check the air pressure tubing to the fitting on the of the air intake chamber box and route tubing in molded inlaid of the air intake chamber box (Figure 63). 27.
AIR INTAKE CHAMBER FAN REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Tools required: Phillips Head Screwdriver. Figure 68. COOLER HOTTER Electronic Control Display Removing the Fan from the Air Intake Chamber: 1.
Installing the Fan in the Air Intake Chamber Box: 11. Plug the electrical connections of the new fan into the wiring harness: Align the electrical connections in such a position as to ensure the locking portions of the connections are on the same side. Gently push the electrical connectors together until the snap lock on the wiring harness engages the angular lock on the fan connector. Do Not use undue force in pushing these connectors together (Figure 71).
PRESSURE TUBING REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Tools required: Phillips Head Screwdriver. Figure 74. COOLER HOTTER Electronic Control Display Removing the Air Intake Chamber Box: 1.
Installing the Air Intake Chamber Box: 11. Check the position the wiring harness wire in the wiring channeling molded down the back center of the air intake chamber box (Figure 78). 12. Connect the air pressure tubing to the fitting on the bottom of the air intake chamber box and route tubing in molded inlaid of the air intake chamber box (Figure 78). 13. Reinstall the air intake chamber gasket (removed in step 7) on the back lower portion of the air intake chamber box (Figure 79). 14.
INNER DOOR/MANIFOLD/BURNER ASSEMBLY REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Tools required: 3/4” Open-End Wrench or Crescent Wrench, Phillips Head Screwdriver, Ratchet with 1/4” socket or 1/4” Nut Driver. Figure 81. COOLER HOTTER Electronic Control Display Figure 82.
Installation Caution Must Be Taken: 10. Prior to installing the new inner door/manifold/ burner assembly, look inside the burner chamber to fully understand the correct positioning of the burner assembly and burner manifold tab. It may be necessary to use a flashlight to ensure correct placement. Care must be taken so as to not damage any electrical wiring, components or the air pressure tubing as you are installing the new inner door/manifold/burner assembly.
FLAME SENSE/HOT SURFACE IGNITER REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Tools required: 3/4” Open-End Wrench or Crescent Wrench, Phillips Head Screwdriver, Ratchet with 1/4” socket or 1/4” Nut Driver. Figure 89. COOLER HOTTER Replacing the Flame Sense/Hot Surface Igniter Assembly: 1.
BURNER REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Tools required: 3/4” Open-End Wrench or Crescent Wrench, Phillips Head Screwdriver, Ratchet with 1/4” socket or 1/4” Nut Driver. Figure 93. COOLER HOTTER Removing the Inner Door/Manifold/Burner Assembly: 1.
Removing Old Burner : 11. After noting the position of the condensation drain hole on the top of the burner. Turn the inner door/ manifold/burner assembly upside. Using a phillips head screwdriver remove the 2 screws attaching the burner to the manifold pipe (saving screws for reinstallation later) (Figure 99). Figure 97. 1/4” HEX HEAD SCREW Installing New Burner : 12. Care MUST be taken to ensure the burner is installed correctly on the inner door/manifold assembly.
16. After confirming no material of any type are between door gasket and combustion chamber shield, align the screws on the inner door with the screw holes on the combustion chamber and tighten with 1/4” nut driver or 1/4” socket & ratchet (Figure 97). After tightening the inner door screws, visually inspect area around door gasket and skirt for spaces or gaps. The door gasket MUST be sealed completely in order for the water heater to perform properly.
BURNER ORIFICE REMOVAL / REPLACEMENT g Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Tools required: 3/4” Open-End Wrench or Crescent Wrench, Phillips Head Screwdriver, Ratchet with 1/4” socket or 1/4” Nut Driver, Ratchet with 1/2” socket. Figure 102. COOLER HOTTER Electronic Control Display Removing the Inner Door/Manifold/Burner Assembly: 1.
Removing Old Burner Orifice : 11. Burner may be hot, wait until burner has cooled off. After noting the position of the condensation drain hole on the top of the burner. Turn the inner door/manifold/burner assembly upside. Using a phillips head screwdriver remove the 2 screws attaching the burner to the manifold pipe (saving screws for reinstallation later) (Figure 108). 12.
Reinstalling The Inner Door/Manifold/Burner Assembly 17. Insert the manifold/burner assembly in the burner chamber compartment, making sure that the tip of burner manifold tab engages in the slot of the bracket (Figure 107). The tip end of the burner manifold MUST be placed in the slotted portion under the condensation pan to obtain proper installation (Figure 107). 18.
GAS CONTROL VALVE/THERMOSTAT REMOVAL / REPLACEMENT Important: Use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get help from a qualified service technician. Tools required: 3/4” Open-End Wrench or Crescent Wrench, Phillips Head Screwdriver, a short length of 1/2” threaded Pipe. g Figure 112. COOLER HOTTER Removing the Gas Control Valve/Thermostat: 1.
11. Ensuring that the gas supply line is turned off, disconnect the gas piping at the ground joint union, then remove the gas piping from the gas control valve/ thermostat (Figure 116). Figure 116. GAS SHUT-OFF 12. Remove any other fittings that may be installed on the threaded pipe to the gas control valve/thermostat (Figure 116). GROUND JOINT UNION 13.
23. Turn on the gas supply to the unit and test the gas supply line and union connections by brushing on an approved noncorrosive leak detection solution (Figure 116). 24. Turn on the electrical and the gas supplies to the water heater. Plug in the electric connection from the transformer to the electric outlet (Figure 113). 25. Restart the water heater by following the directions on the “Lighting and Operating Instructions” label located on the front of the water heater . 26.
GAS WATER HEATER SIZING GUIDE Use the following information as a guide to approximate the correct size water heater for the residence: • 40 gallon size (28 gallon draw) for two bath residence -or one bath with an automatic clothes washer. • 50 gallon size (35 gallon draw) for three bath residence - or two baths with an automatic clothes washer.
GENERAL INFORMATION Draw efficiency is the quantity of hot water available to the consumer before the outlet water temperature decreases 25 degrees F. A 40 gallon water heater will typically provide 70% (28 gallons) of this “usable” hot water (60% is the minimum). The burner or elements are allowed to operate during this test. Incoming, cold water mixes the remaining stored water below this 25 degree limitation.
GENERAL INFORMATION One pound of gas pressure is equal to 27.7 inches water column pressure Inches of Water Column X .036091 = PSI Inches of Water Column X .073483 = Inches of Mercury (Hg.) Centimeters = Inches X 2.54 MM (millimeters) =Inches X 25.4 Meters = Inches X .0254 Doubling the diameter of a pipe will increase its flow capacity (approximately) 5.3 times. Construction: Tank is constructed of steel. The inside of the tank is constructed of a glass lining bonded to the steel.
ALL TECHNICAL AND WARRANTY QUESTIONS SHOULD BE DIRECTED TO THE LOCAL DEALER FROM WHOM THE WATER HEATER WAS PURCHASED. IF YOU ARE UNSUCCESSFUL, CONTACT A O SMITH WATER HEATERS RESIDENTIAL TECHNICAL ASSISTANCE AT 1-800-527-1953 OR WWW.HOTWATER.COM.
