A.O. Smith GAHH 50 100 manual

1 Printed in U.S.A. 10/10 318181-000 SER VICE HANDBOOK FOR ST ANDARD RESIDENTIAL HIGH EFFICIENCY A TMOSPHERIC VENT (FVIR) GAS W A TER HEA TERS 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, PCG2J5[...]

2 ALL TECHNICAL AND W ARRANTY QUESTIONS SHOULD BE DIRECTED T O THE LOCAL DEALER FROM WHOM THE W A TER HEA TER W AS PURCHASED. IF YOU ARE UNSUCCESSFUL, CONT ACT A. O. SMITH WA TER HEA TERS RESIDENTIAL TECHNICAL ASSIST ANCE A T 1-800-527-1953 OR WWW .HOTWA TER.COM.[...]

3 Y our 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 importa[...]

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. Maintain required clearances to combustibles. Keep[...]

5 T ABLE OF CONTENTS INTRODUCTION: Service Handbook Introduction ................................................................................................. ..........................3 W arnings and Cautions .......................................................................................................................................4[...]

6 Exhaust V ent to Ouside of Building Union Union W ater Shut-Off Va l v e W ater Supply- Cold* Expansion T ank Pressurize to Equal Supply W ater Pressure* (Relieve water pressure on the expansion tank before adjusting air pressure.) T emperature-Pressure Relief V alve with discharge piped to an adequate drain. Do not cap or plug. 6” Maximum Air [...]

7 COMBUSTION AIR AND VENT SYSTEM REQUIREMENTS T able 1: BTUH Input Minimum Square Feet with 8’ Ceiling T ypical 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 IMPORT ANT : • The area must be open and be able to pro v[...]

8 COMBUSTION AIR AND VENT SYSTEM REQUIREMENTS All Air from Inside the Building: When additional air is to be provided to the con fi ned area from additional room(s) within the building, the total volume of the room(s) must be of suf fi cient size to properly provide the necessary amount of fresh air to the water heater and other gas utilization e[...]

9 COMBUSTION AIR AND VENT SYSTEM REQUIREMENTS V ent Connectors: 1 . T ype B, Double wall , U.L. Listed V ent Pipe . 2. Single wall V ent P ipe. Maintain the manufacturer ’ s speci fi ed minimum clearance from combustible materials when using type B double wall vent pipe. V ent connectors made of type B, double wall vent pipe material may pass th[...]

10 • The connec t or must be f irmly attac h ed and sealed to pre vent it from falling out. • T o aid in removing the connector , a thimble or slip joint ma y be used. • The connec t or must not extend be yond the inner edge of the chimney as it ma y restrict the space bet w een it and the opposite wall of the chimney Chimney Termination Vent[...]

11 KNOW THE W A TER HEA TER’S COMPONENT P ARTS Figure 1 1. 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 Fah[...]

12 KNOW THE W A TER HEA TER’S COMPONENT P ARTS 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 NOT operate the water heater without the bu[...]

13 KNOW THE W A TER HEA TER’S COMPONENT P ARTS Flammable V apor 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 inoper[...]

14 W A TER HEA TER OPERA TION 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 ele[...]

15 FILLING, DRAINING AND FLUSHING THE W A TER HEA TER T ANK 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. T o drain the tank, perform the following steps: Adequate Drain Hose Outer Door [...]

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/Off Switch” and needs to be turned on befor[...]

17 ADJUSTING THE TEMPERA TURE ON THE ELECTRONIC CONTROL DISPLA Y Adjusting the T emperature 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 a[...]

18 USING THE ELECTRONIC CONTROL DISPLA Y 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. T o 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 ente[...]

19 USING THE ELECTRONIC CONTROL DISPLA Y 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[...]

20 Please check g uidelines bel ow. For your safety, w ater heater servic e should be perf ormed only by a q ualied service person. Read the GEN E RA L SAFETY INFORMAT ION supplied b y th e water heater manuf acturer. 1. “POWER” F lashing Communication Error The system has detected a communication error between the upper and lower controls. [...]

21 6. “P-S W”, “OPEN ”, and “CL EA N SC REEN” Flas hing The air pressure switch contacts remain open longer than 11 seconds aft er 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. En sure t he pressure switch sensing t[...]

22 CONTROL DISPLA Y TROUBLESHOOTING 11. “FV-SEN SE” a nd “OPEN ” Flash ing Flammable Vapor Sensor is open 1. Check all wiring to the a mmable vapor sensor. 2. Remove the connectors from the ammable vapor sensor and measure the resistance of the sensor with an ohmmeter . A. If the reading taken is more than 1.7 million ohms, repla ce t[...]

23 Please Note: Th e co ntro l continually monitors internal circuits and extern a l se nso rs. Error codes noted abov e, and tho se f or self-diagnostic faults can be f ound on pages 20 through 22. APPLY POWER T O APPLIA N CE YES REQUEST FOR HEAT PRESENT? NO IS PRESSURE SWI TCH PROVEN OPEN WI THIN 5 SECONDS? NO COMBUSTION FAN ON YES IS PRESSURE SW[...]

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 or dirt, it may be necessary to check the air i[...]

25 ELECTRONIC CONTROL DISPLA Y REMOV AL / 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 . Set the gas control valv e/thermost a t to its l[...]

26 POWERED ANODE ROD REMOV AL / 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. T ools required: Ratchet with 1- 1/16 ” Socket, Pliers, and T eflon ® T ape or an approved pipe seal[...]

27 Installing the Powered Anode Rod: 8. Use T eflon ® tape or an appro ved pipe sealant on threads of the new po wered anode rod. 9. Prior to installing, it will be necessar y to use pliers to bend up appro ximately 90° the elec trical male connec t or on the top of the powe red anode rod. The electric al connector should be bent upw ard in order[...]

28 PRESSURE SWITCH REMOV AL / 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. T ools required: Phillips Head Screwdriver . Removing the Pressure Switch: 1 . Set the gas control valv e[...]

29 TRANSFORMER REMOV AL / REPLACEMENT g C OOLER HO T TER Electronic Control Display Fig ure 40. ON/OFF SWITCH ON OFF Fig ure 4 1 . UNPL UGGED 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. T ool[...]

30 Installing the New T ransformer: 1 0. Inser t the wiring c onnector tha t goes to the gas control valv e/ther mostat through the wire pro tector on the side of the transformer box ( Figure 4 4 ). 1 1 . At tach the t w o (2 ) flag terminal co nnectors to the transformer by aligning and pressing down (Fig ure 4 4 ). 1 2. Position the new transform[...]

31 AIR INT AKE CHAMBER BOX REMOV AL / 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. T ools required: Phillips Head Screwdriver . Removing the Air Intake Chamber Box: 1 . Set the gas[...]

32 1 4. Rotate the t op of the air intake chamber bo x from left to r igh t ( only a few inches in both directions ) while pulling outward at the bottom removing the air intak e chamber box from the combustion chamber pipe saving the air intak e chamber gask et for reinstallation (Figure 49 ). 1 5. Unplug the air pressure tubing from the back of th[...]

33 Fig ure 53. SECURE WITH SCREWS REMOVED EARLIER 25. Install the air intake chamber bo x by rotating the top of the air in t a ke chamber box from le f t to right ( only a few inches in both directions ) while pressing on the bottom por tion of the air intak e chamber box. When properly installed the air intak e chamber box will be in place agains[...]

34 WIRING HARNESS REMOV AL / 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. T ools required: Phillips Head Screwdriver . Removing the Air Intake Chamber Box: 1 . Set the gas control [...]

35 Replacing the Wiring Harness: 1 3. Locate the male to female electric al connection with close pin lock on wir ing harness (located on the right side of fan ) ( Figure 62 ). 1 4. T o separate the electric al connection of the fan and wiring harness: press down on the back por tion of the close pin lock of the electric al connec tion while pull i[...]

36 25. Install the air intake chamber screen, ensuring that the prongs of the low er por tion of the air intak e chamber screen are in plac e in the hold ing slots. Using the 2 screws remov ed in step 8, secure the air intak e c hamber screen (F igure 65). 26. Check the air pressure tubing to the fit ting on the of the air intak e chamber box and r[...]

37 AIR INT AKE CHAMBER F AN REMOV AL / 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. T ools required: Phillips Head Screwdriver . Removing the Fan from the Air Intake Chamber: 1 . S[...]

38 Installing the Fan in the Air Intake Chamber Box: 1 1 . Plug the electr ical connections of the new fan into the wiring harness: Align the electric al connec tions in s uch a position as to ensure the locking por tions of the connections are on the same side. Gently push the electric al connectors together un til the snap lock on the wir ing har[...]

39 PRESSURE TUBING REMOV AL / 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. T ools required: Phillips Head Screwdriver . Removing the Air Intake Chamber Box: 1 . Set the gas control[...]

40 Installing the Air Intake Chamber Box: 1 1 . Check the position the wir ing harness wire in the wiring channeling molded down the back center of the air intak e chamber box (Figure 7 8 ). 1 2. Connec t the air pressu re tubing to the f itting on the bottom of the air intak e chamber box and route tubing in molded inlaid of the air intak e chambe[...]

41 INNER DOOR/MANIFOLD/BURNER ASSEMBL Y REMOV AL / 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. T ools required: 3/4” Open-End Wrench or Crescent Wrench, Phillips Head Screwdrive[...]

42 Install ation Caution Must B e T a k en: 1 0. Prior to installing the new inner door/ manifold/ burner assembly , look inside the burner chamber to fully understand the cor rect positioning of the burner assembly and bur ner manifold tab . It may be necessar y to use a f lashl ight to ensure correc t placement. Care must be tak en so as to not d[...]

43 FLAME SENSE/HOT SURF ACE IGNITER REMOV AL / 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. T ools required: 3/4” Open-End Wrench or Crescent Wrench, Phillips Head Screwdriver , [...]

44 BURNER REMOV AL / 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. T ools required: 3/4” Open-End Wrench or Crescent Wrench, Phillips Head Screwdriver , Ratchet with 1/4” socket[...]

45 Removing Old Burn er : 1 1 . Af ter noting the position of the c ondensa tion drain hole on the top of the burner . T urn the inner door/ manifold/bur ner assembly upside . Using a phillips head screwdriver remo ve the 2 screws attaching the burner to the manifold pipe ( saving screws for reinstallation later ) (Figure 99) . Installing N ew Burn[...]

46 1 6. Af ter confir ming no mat er i al of any type are between door gaske t and c ombustion chamber shield, align the screws on the inner door with the screw holes on the combustion chamber and tighten with 1 /4” nu t driver or 1 /4 ” socket & ra tchet (Figure 9 7). Afte r tightening th e inner door screws, visually inspec t area around [...]

47 BURNER ORIFICE REMOV AL / REPLACEMENT g C OOLER HO T TER Electronic Control Display Fig ure 1 02 . ON/OFF SWITCH ON OFF Fig ure 1 03 . UNPL UGGED 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[...]

48 Removing Old Burn er Orif ice : 1 1 . Bur ner ma y be hot, wait u ntil burner has c ooled of f . After noting the position of the condensation drain hole on the top of the burner . T urn the inner door/ manifold/ burner assembly upside. Using a phillips head screwdriver remo ve the 2 screws attac h ing the bur ner t o the manifold pipe ( saving [...]

49 Reinstalling The I nner Door/Manifold /Burner Asse mbly 1 7 . Inser t the manifold/ burner assembly in the burner chamber compar tment, making sure that the tip of burner manifold tab engages in the slot of the bracke t (Figure 1 0 7). The tip end of the burner manifold M U ST be placed in the slotted por tion under the condensation pan to obtai[...]

50 GAS CONTROL V AL VE/THERMOST A T REMOV AL / 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. T ools required: 3/4” Open-End Wrench or Crescent Wrench, Phillips Head Screwdriver , [...]

51 1 1 . Ensuring that the gas supply line is tur ned off, disconnec t the gas piping at the ground joint union, then remove the gas piping from the gas c ontrol valv e/ thermostat (Figur e 1 16 ) . 1 2. Remove an y other f itt ings that ma y be installe d on the threaded pipe to t he gas control valve/ther mostat (Figure 1 1 6) . 1 3. Af ter ensur[...]

52 23. T urn on the gas supply to the unit and tes t the gas supply line and un ion c onnections b y br ushing on an approv ed noncor rosiv e leak detection solution (Figure 1 16 ) . 24 . T urn on the electr ical and the gas supplies to the wat er heater . Plug in the electric c onnection from the transformer to the electr ic ou tlet (Figure 1 1 3 [...]

53 * T o 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 W ater Heater” section and then remove fi tting. Put pipe dope or T e fl on ® tape on the threads and replace. When you are fi nished, follow the steps in “Filling [...]

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 this test. Incoming, cold water mixes the re[...]

55 One pound of gas pressure is equal to 27.7 inches water column pressure Inches of W ater Column X .036091 = PSI Inches of W ater 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. [...]

56 ALL TECHNICAL AND W ARRANTY QUESTIONS SHOULD BE DIRECTED TO THE LOCAL DEALER FROM WHOM THE WA TER HEA TER W AS PURCHASED. IF YOU ARE UNSUCCESSFUL, CONT ACT A O SMITH WA TER HEA TERS RESIDENTIAL TECHNICAL ASSIST ANCE A T 1-800-527-1953 OR WWW .HOTW A TER.COM.[...]