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  4. 12 40GPC T 100
  5. Service Handbook

A.O. Smith 12 40GPC T 100 Service Handbook

Manual is about: STANDARD RESIDENTIAL HIGH EFFICIENCY ATMOSPHERIC VENT (FVIR) GAS WATER HEATERS

Summary of 12 40GPC T 100

  • Page 1

    1 printed in u.S.A. 10/10 318181-000 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...

  • Page 2

    2 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..

  • Page 3

    3 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 instructi...

  • Page 4

    4 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. Use only gas shown on rating plate. ...

  • Page 5

    5 table of contents introduction: service handbook introduction ...........................................................................................................................3 warnings and cautions ............................................................................................

  • Page 6

    6 exhaust vent to ouside of building union union water shut-off valve water supply- cold* expansion tank pressurize to equal supply water pressure* (relieve water pressure on the expansion tank before adjusting air pressure.) temperature-pressure relief valve with discharge piped to an adequate drai...

  • Page 7: Warning

    7 combustion air and vent system requirements table 1: btuh input minimum square feet with 8’ ceiling typical room with 8’ ceiling 30,000 188 9 x 21 45,000 281 14 x 20 60,000 375 15 x 25 75,000 469 15 x 31 90,000 563 20 x 28 105,000 657 20 x 33 120,000 750 25 x 30 135,000 844 28 x 30 important: • th...

  • Page 8

    8 combustion air and vent system requirements all air from inside the building: when additional air is to be provided to the confi ned area from additional room(s) within the building, the total volume of the room(s) must be of suffi cient size to properly provide the necessary amount of fresh air t...

  • Page 9

    9 combustion air and vent system requirements vent connectors: 1. Type b, double wall, u.L. Listed vent pipe. 2. Single wall vent pipe. Maintain the manufacturer’s specifi ed minimum clearance from combustible materials when using type b double wall vent pipe. Vent connectors made of type b, double ...

  • Page 10

    10 • 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. • the connector must not extend beyond the inner edge of the chimney as it may restrict the space between it and the opposite wall of the chi...

  • Page 11

    11 know the water heater’s component parts figure 11. 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 s...

  • Page 12

    12 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). *do n...

  • Page 13

    13 know the water heater’s component parts 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 v...

  • Page 14

    14 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 wi...

  • Page 15

    15 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 fol...

  • Page 16

    16 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...

  • Page 17

    17 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 electron...

  • Page 18

    18 using the electronic control display how to select or change the temperature scale from fahrenheit (°f) to celsius (°c). Figure 22. 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 ...

  • Page 19

    19 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 aut...

  • Page 20

    20 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. 1. “power” flashing communication error the system has detected a communication error between...

  • Page 21

    21 6. “p-sw”, “open”, and “clean screen” flashing 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 2. Ensure the pres...

  • Page 22

    22 control display troubleshooting 11. “fv-sense” and “open” flashing flammable vapor sensor is open 1. Check all wiring to the flammable vapor sensor. 2. Remove the connectors from the flammable vapor sensor and measure the resistance of the sensor with an ohmmeter. A. If the reading taken is more ...

  • Page 23

    23 please note: the control continually monitors internal circuits and external sensors. Error codes noted above, and those for self-diagnostic faults can be found on pages 20 through 22. Apply power to appliance yes request for heat present? No is pressure switch proven open within 5 seconds? No co...

  • Page 24

    24 external inspection and cleaning cleaning the air intake chamber screen: • 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...

  • Page 25

    25 electronic control display 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. Removing the electronic control display: 1. S...

  • Page 26

    26 powered anode rod 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: ratchet with 1-1/16” socket, pliers, a...

  • Page 27

    27 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 con...

  • Page 28

    28 pressure switch 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: phillips head screwdriver. Removing the ...

  • Page 29

    29 transformer removal / replacement g cooler hotter electronic control display figure 40. On/off switch on off figure 41. Unplugged 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 f...

  • Page 30

    30 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...

  • Page 31

    31 air intake chamber box 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: phillips head screwdriver. Removi...

  • Page 32

    32 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 a...

  • Page 33

    33 figure 53. Secure with screws removed earlier 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 inta...

  • Page 34

    34 wiring harness 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: phillips head screwdriver. Removing the a...

  • Page 35

    35 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 ...

  • Page 36

    36 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 ...

  • Page 37

    37 air intake chamber fan 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: phillips head screwdriver. Removi...

  • Page 38

    38 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 togeth...

  • Page 39

    39 pressure tubing 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: phillips head screwdriver. Removing the ...

  • Page 40

    40 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 ...

  • Page 41

    41 inner door/manifold/burner assembly 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...

  • Page 42

    42 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....

  • Page 43

    43 flame sense/hot surface igniter 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 ...

  • Page 44

    44 burner 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...

  • Page 45

    45 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 late...

  • Page 46

    46 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, visu...

  • Page 47

    47 burner orifice removal / replacement g cooler hotter electronic control display figure 102. On/off switch on off figure 103. Unplugged important: use only factory authorized replacement parts. If you lack the necessary skills to properly perform the installation, you should not proceed, but get h...

  • Page 48

    48 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...

  • Page 49

    49 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...

  • Page 50

    50 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 cre...

  • Page 51

    51 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). 12. Remove any other fittings that may be installed on the threaded pipe to the gas control valve/thermostat (f...

  • Page 52

    52 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 ...

  • Page 53

    53 * to check where threaded portion enters tank, insert cotton swab between jacket opening and fi tting. If cotton is wet, follow draining instructions in the “draining the water heater” section and then remove fi tting. Put pipe dope or tefl on ® tape on the threads and replace. When you are fi ni...

  • Page 54

    54 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...

  • Page 55

    55 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 increa...

  • Page 56

    56 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..