A.O. Smith GAHH-50 Service Manual

1This water heater complies with ANSI Z21.10.1-current edition regarding the accidental or unintended ignition of fl ammable vapors, such as those emit

10WARNING• Use a new CSA approved gas supply line.• Install a shut-off valve.• Do not connect a natural gas water heater to an L.P. gas supply.•

11TABLE 3BTUH InputMinimum SquareFeet with8’ CeilingTypical Roomwith 8’ Ceiling30,000 188 9 x 2145,000 281 14 x 2060,000 375 15 x 2575,000 469 15 x 31

1212” Max.Permanentopenings to the outside oradditional rooms within the buildingClosetor otherconfinedspace12” Max.FIGURE 4.All Air from Inside the B

13FIGURE 8B.Vent Pipe System This water heater uses a non-direct, single-pipe vent system to remove

1440 Gal. Water Heater: Align the reducer flue over top of baffle as shown in Figure 9 (NOTE: reducer flue must be installed on 40 gal. water heater a

15Piping Installation Piping, fittings, and valves should be installed according to the installation

16Hot WaterOutletIn a closed system use athermal expansion tankCold WaterInlet ValvePressure ReducingValve with BypassMain WaterSupplyCold Water Suppl

17For protection against excessive pressures and temperatures, a temperature and pressure relief valve must be installed in the opening marked “T &

18A diaphragm-type expansion tank suitable for potable water will normally eliminate this weeping condition. Please read and follow the manufacturer’s

19□ Ductwork is the same cross-sectional area as the openings.Vent Pipe SystemCheck for proper drafting at the water heater draft hood. Refer to the

2TABLE OF CONTENTSWater Heater Safety ...

20WARNINGExplosion HazardReplace view port if glass is missingor damaged.Failure to do so can result in death,explosion or fire.Operating Instructions

21If the flame flutters or is blown out, combustion products are escaping from the relief opening. If this occurs, do not operate the water heater unt

22Burner FlamesInspect the burner flames through the viewport and compare them to the drawings in Figure 19. A properly operating burner should produc

23Good venting is essential for a gas fired water heater to operate properly as well as to carry away products of combustion and water vapor. It is al

24Powered Anode OperationTo protect the glass-lined water tank from corrosion through electrolysis, this water heater is equipped with a non sacrifici

25properly. To prevent water damage, the valve must be pro- perly connected to a discharge line which terminates at an adequate drain. Standing clear

26Replacing the Flame Sense/Hot Surface igniter Assembly1. Remove the manifold/burner assembly. See Removing the Manifold/Burner Assembly.2. Lift th

273. Insert the manifold/burner assembly into the burner compartment making sure that the tip of the manifold tube engages in the slot of the bracket

28TROUBLESHOOTING CHARTPROBLEM POSSIBLE CAUSE(S) CORRECTIVE ACTIONNO HOT WATER1. Transformer unplugged.2. No power at outlet.3. Thermostat defec

29PROBLEM POSSIBLE CAUSE(S) CORRECTIVE ACTIONWATER LEAKS1. Improperly sealed, hot or cold supply connections, relief valve, drain valve or thermosta

3SAFE INSTALLATION, USE AND SERVICEYour safety and the safety of others is extremely important in the installation, use and servicing of this water he

30 Please check guidelines below. For your safety, water heater service should be performed only by a qualied service person.Read the GENERAL SAFETY

31 6. “P-SW”, “OPEN”, and “CLEAN SCREEN” Flashing The air pressure switch contacts remain open longer than 11 seconds after the combustion fan is e

32 11. “FV-SENSE” and “OPEN” Flashing Flammable Vapor Sensor is open 1. Check all wiring to the ammable vapor sensor. 2. Remove the connectors

33Please Note:The control continually monitorsinternal circuits and external sensors.Error codes noted above, and those forself-diagnostic faults can

34Item No.Parts Description1 Draft Hood2 Flue Baffle3 Nipple (Hot)4 Nipple (Cold)5 Anode Rod6 Cold Water Inlet Tube7 Temperature and Pressure Valve8 C

35Listed Parts Kits and Illustrations

36NOTES

37NOTES

38NOTES

39THIS WARRANTY IS APPLICABLE TO THE ORIGINAL OWNER ONLY in accordance with the warranty terms and conditions specifi ed below.The warrantor will furni

4Breathing Hazard - Carbon Monoxide GasInstall vent system in accordance withcodes.Do not operate water heater if flooddamagedHeater should not be ins

40LIMITATION ON IMPLIED WARRANTIESImplied warranties, including any warranty of merchantability imposed on the sale of this heater under state law are

5TYPICAL INSTALLATIONGET TO KNOW YOUR WATER HEATER - GAS MODELS A Vent Pipe B Draft hood C Anode (Not Shown) D Hot Water Outlet E Insulation F

6INSTALLING YOUR GAS WATER HEATERImportant Information About This Water Heater This gas water heater was manufactured to voluntary safety standa

7Location Requirements Carbon Monoxide Poisoning HazardWARNINGDo not install in a mobile home. Doing so

8IMPORTANT: The water heater should be located in an area where leakage of the tank or connections will not result in damage to the area adjacent to t

9Manual GasShut-Off ValveInstall a readily acces-sible manual shut-off valve in the gas supply line as recommended by the local utility.Check with loc