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A.O. Smith GDHE-50 Instruction Manual

Manual is about: resIdentIal Gas water heaters

Summary of GDHE-50

  • Page 1

    Instruction manual printed 0413 322286-002 keep this manual in the pocket on heater for future reference whenever maintenance adjustment or service is required. Power vent/power direct vent gas models with hot surface ignition model gdhe 50 series 124/125 complies with scaqmd low nox rule 1146.2 all...

  • Page 2: Table Of Contents

    2 table of contents general safety information .............................................4 precautions ................................................................................4 grounding instructions ...............................................................4 hydrogen gas flammable ....

  • Page 3: Approvals

    3 the proper installation, use and servicing of this water heater is extremely important to your safety and the safety of others. Many safety-related messages and instructions have been provided in this manual and on your own water heater to warn you and others of a potential injury hazard. Read and...

  • Page 4: Caution

    4 precautions do not use this appliance if any part has been under water. Immediately call a qualified service agency to inspect the appliance and to make a determination on what steps should be taken next. If the unit is exposed to the following, do not operate heater until all corrective steps hav...

  • Page 5: General Safety Information

    5 general safety information.

  • Page 6: Caution

    6 fire hazard do not install water heater on carpeted floor. Do not operate water heater if flood damaged. For continued protection against risk of fire: fire or explosion hazard read instruction manual before installing, using or servicing water heater. Avoid all ignition sources if you smell gas. ...

  • Page 7: Introduction

    7 thank you for purchasing this water heater. Properly installed and maintained, it should give you years of trouble free service. Abbreviations used abbreviations found in this instruction manual include : • ansi - american national standards institute • asme - american society of mechanical engine...

  • Page 8: Features And Components

    8 * caution harness has 120 vac. In operation. ** see “planning the vent system,” “installation of vent system” and “condensate piping” for more information. Figure 1. Vacuum relief valve *install per local codes m display enclosure ** n exhaust elbow assembly ** o condensate tubing p off/on switch ...

  • Page 9: Installation Consideration

    9 rough in dimensions installation consideration table 1 – rough-in-dimensions units a b c d e f g h i inches 66.75 49.25 22.00 15.75 3.00 8.00 8.00 62.00 65.00 cm 169.5 125.09 55.88 40.00 7.62 20.32 20.32 157.48 165.1 top/side inlet and outlet: 3/4” npt gas inlet: 1/2” npt table 2 – capacity, gas a...

  • Page 10: Caution

    10 locating the water heater carefully choose a location for the new water heater. The placement is a very important consideration for the safety of the occupants in the building and for the most economical use of the appliance. Property damage hazard all water heaters eventually leak. • do not inst...

  • Page 11

    11 in an alcove or closet, the entire floor must be covered by the panel. Failure to heed this warning may result in a fire hazard. Minimum clearances between the water heater and combustible construction are 0 inch at the sides and rear, 5.5” (14.0 cm) from the front and 18” (45.7 cm) from the top....

  • Page 12

    12 ventilation systems, clothes dryers and fireplaces shall also be considered in determining the adequacy of a space to provide combustion, ventilation and dilution air. Unusually tight construction in unconfined spaces in buildings, infiltration may be adequate to provide air for combustion, venti...

  • Page 13

    13 1. 1 square inch per 3000 btu/hr (733 mm 2 per kw) of the total input rating of all appliances located in the enclosure, and 2. Not less than the sum of the areas of all vent connectors in the space. Outdoor air through two horizontal ducts figure 6. The confined space shall be provided with two ...

  • Page 14

    14 this water heater shall not be connected to any heating systems or component(s) used with a non-potable water heating appliance. All piping components connected to this unit for space heating applications shall be suitable for use with potable water. Toxic chemicals, such as those used for boiler...

  • Page 15

    15 mixing valves water temperature over 125°f (52°c) can cause severe burns instantly resulting in severe injury or death. Children, the elderly and the physically or mentally disabled are at highest risk for scald injury. Feel water before bathing or showering. Temperature limiting devices such as ...

  • Page 16

    16 figure 9. Close water systems water supply systems may, because of code requirements or such conditions as high line pressure, among others, have installed devices such as pressure reducing valves, check valves, and back flow preventers. Devices such as these cause the water system to be a closed...

  • Page 17: Caution

    17 t&p relief valve insulation manual relief lever t&p relief valve t&p relief valve drain line figure 11. Temperature-pressure relief valve explosion hazard temperature-pressure relief valve must comply with ansi z21.22- csa 4.4 and asme code. Properly sized temperature- pressure relief valve must ...

  • Page 18

    18 gas piping make sure gas supplied is same type listed on model rating plate. The inlet gas pressure must not exceed 14 inch water column (3.5 kpa) for natural and propane gas (l.P.). The minimum inlet gas pressure shown on rating plate is that which will permit firing at rated input. Sediment tra...

  • Page 19

    19 the bottom of the unit (see figure 12). Condensate from this water heater is mildly acidic. Please note that some local codes require that condensate is treated by using a ph neutralizing filter prior to disposal. Caution must be used to ensure that the drain is free and clear of debris and will ...

  • Page 20

    20 venting never operate the water heater unless it is vented to the outdoors. The instructions in this section of the manual must be followed to avoid choked combustion or recirculation of flue gases. Such conditions cause sooting of the combustion chamber, burners and flue tubes and creates a risk...

  • Page 21

    21 pvc materials should use astm d-2564 grade cement; cpvc materials should use astm f-493 grade cement and abs materials should use astm d-2235 grade cement. If the water heater is being installed as a replacement for an existing power vented heater in pre-existing venting, a thorough inspection of...

  • Page 22

    22 commonwealth of massachusetts for all side wall terminated, horizontally vented power vent, direct vent, and power direct vent gas fueled water heaters installed in every dwelling, building or structure used in whole or in part for residential purposes, including those owned or operated by the co...

  • Page 23

    23 termination clearances sidewall power vent v x vent terminal air supply inlet area where terminal is not permitted v v a g v fixed closed fixed closed operable operable v c b b b b f b v v a j v h m x x v v k b e d l power vent (using room air for combustion) exterior clearances for sidewall vent...

  • Page 24

    24 termination clearances sidewall direct vent v x vent terminal air supply inlet area where terminal is not permitted v v a g v fixed closed fixed closed operable operable v c b b b b f b v v a j v h m x x v v k b e d l direct vent (using outdoor air for combustion) exterior clearances for sidewall...

  • Page 25

    25 sequence of installations, figure 15a cut a length of pvc pipe about 3.5 inches (8.9 cm) longer than the wall thickness at the opening. Glue the vent terminal to this section of pipe. Slide the wall plate over the pipe to stop against the vent terminal. Place a bead of caulking (not supplied) aro...

  • Page 26

    26 vertical vent terminal installation when terminating through a roof, the following specifications pertaining to terminal location must be followed. 1. Proper support must be provided for all pipe protruding through the roof. 2. The vertical roof terminations should be sealed with a plumbing roof ...

  • Page 27

    27 concentric vent installation this water heater is certified for concentric venting with concentric vent kit #9006328005. Follow instructions below for proper installations. Table 6 - kit components each kit is comprised of the following: item description qty. Rain cap 3 in. 1 sdr-26 pipe 4 in. Di...

  • Page 28

    28 5. Secure assembly to roof structure as shown in figure 23 using field supplied metal strapping or equivalent support material. Note: ensure termination height is above the roof surface or anticipated snow level as shown in figure 23. 6. Install rain cap and small diameter pipe assembly in roof p...

  • Page 29

    29 5. Install rain cap and small diameter pipe assembly in y concentric fitting and large pipe assembly. Ensure small diameter pipe is bottomed and cemented in y concentric fitting. 6. Secure assembly to structure as shown in figure 24 using field- supplied metal strapping or equivalent support mate...

  • Page 30: Direct Vent Diagram

    30 12” minimum clearance above highest anticipated snow level 12” minimum clearance above highest anticipated snow level 24” minimum separation. Exhaust must be at same level or above intake terminal. Direct vent diagram figure 28. Figure 30. Figure 31. Figure 32. Figure 29. When direct venting thro...

  • Page 31

    31 vent pipe preparation 1. Initial preparation. A.) make sure the solvent cement you are planning to use is designed for the specific application you are attempting. B.) know the physical and chemical characteristics and limitations of the pvc and cpvc piping materials that you are about to use. C....

  • Page 32

    32 b. Deburring use a knife, plastic pipe deburring tool, or file to remove burrs from the end of small diameter pipe. Be sure to remove all burrs from around the inside as well as the outside of the pipe. A slight chamfer (bevel) of about 10°-15° should be added to the end to permit easier insertio...

  • Page 33

    33 controls and switches this model is provided with three pressure switches. These switches are essential to the safe and proper operation of the unit. All switches are wired in series. The controller is set up to shut the unit down whenever there is a failure of any of the switches. It is importan...

  • Page 34

    34 caution label all wires prior to disconnection when servicing controls. Wiring errors can cause improper and dangerous operation. Verify proper operation after servicing. Power vent wiring schematic - figure 34. This water heater is polarity sensitve. Before applying electricity to this heater be...

  • Page 35

    35 warning: if you do not follow these instructions exactly, a fire or explosion may result causing property damage, personal injury or loss of life. A. This appliance does not have a pilot. It is equipped with an ignition device which automatically lights the burner. Do not try to light the burner ...

  • Page 36: Temperature Regulation

    36 for the lowest temperature which satisfies your hot water needs. This will also provide the most energy efficient operation of the water heater and minimize scale formation. Valves for reducing the point-of-use temperature by mixing cold and hot water are available, see figure 8. Also available a...

  • Page 37: Control System Operation

    37 user input buttons • the up and down buttons are used to navigate menus and adjust user settings. • the operational buttons are used to enter/exit menus, select menu items, activate adjustment modes and confirm or cancel new user settings. The operational buttons are multifunctional, their curren...

  • Page 38

    38 status icons the status icons are displayed on the desktop screen and convey operational and diagnostic information. The icons are described in the table below. Table 9. Icon description water temperature in the tank has fallen. Shaded area of the animated thermometer icon will rise and fall in r...

  • Page 39

    39 operating states the current operational state of the water heater is displayed on the desktop screen as the "status." the common operational states are described in the table below. Table 10. State description standby the water heater is not in an active heating cycle. Ie: the tank temperature i...

  • Page 40

    40 user settings & control system menus temperatures operating set point and differential adjustment the operating set point is adjustable from 90°f (42°c) to 180°f (82°c) for commercial and 160°f (71°c) on residential models. The factory setting is 120°f (49°c). The differential is adjustable from ...

  • Page 41

    41 temperatures (cont) description/action display • tank temperature - non adjustable - control system sensed temperature from the temperature probe. • tank probe offset - adjustable user setting, range -5° to +5° (factory setting 0°). The tank probe offset is used to calibrate control system temper...

  • Page 42

    42 display settings description/action display select display settings from the main menu and press the operational button under "select" to enter this menu. This menu contains adjustable display options for viewing information on the lcd screen. Use the up & down buttons to navigate the menu. • tem...

  • Page 43

    43 current fault description/action display select current fault from the main menu and press the operational button under "select" to enter this menu. This menu contains non adjustable operational information. Use the up & down buttons to navigate the menu. This menu contains the current fault or a...

  • Page 44

    44 service contact information the control system has a discrete menu that installing contractors and/or service agents can access to enter contact information for their customers. This contact information will be displayed with all fault and alert messages. Description/action display from the deskt...

  • Page 45: For Your Information

    45 start up conditions smoke/odor it is not uncommon to experience a small amount of smoke and odor during the initial start-up. This is due to burning off of oil from metal parts, and will disappear in a short while. Thermal expansion as water is heated, it expands (thermal expansion). In a closed ...

  • Page 46: Periodic Maintenance

    46 venting system inspection at least once a year a visual inspection should be made of the venting system. You should look for: 1. Obstructions which could cause improper venting. The combustion and ventilation air flow must not be obstructed. 2. Damage or deterioration which could cause improper v...

  • Page 47

    47 when checking the temperature-pressure relief valve operation, make sure that (1) no one is in front of or around the outlet of the temperature-pressure relief valve discharge line, and (2) that the water discharge will not cause any property damage, as the water may be extremely hot. Use care wh...

  • Page 48: Leakage Checkpoints

    48 never use this water heater unless it is completely filled with water. To prevent damage to the tank, the tank must be filled with water. Water must flow from the hot water faucet before turning “on” gas to the water heater. A *condensation may be seen on pipes in humid weather or pipe connection...

  • Page 49: Troubleshooting

    49 troubleshooting flow chart. 1. When the control system is first powered, during boot up, it will display water heater model information during initialization. After a few moments the control system lcd which is part of the uim (user interface module) will display the default screen known as the "...

  • Page 50

    50 sequence of operation flow chart yes no water is heated to set point 24 v gas valve de-energized 15 second inter-purge cycle 24 v gas valve de-energized retries up to two more times 60 second post-purge cycle control system locks out “ignition failure” fault msg is displayed water heater goes int...

  • Page 51: Caution

    51 if the main burner ignites momentarily but does not sustain ignition allow the water heater to try to ignite up to two more times until control system locks out and the ignition failure fault message is displayed on the control system's lcd. If the water heater is experiencing rough starts - see ...

  • Page 52

    52 note: if you are not qualified and licensed or certified as required by the authority having jurisdiction to perform a given task do not attempt to perform any of the diagnostic or service procedures described in the following section. If you do not understand the instructions in the following se...

  • Page 53

    53 fault and alert messages call the technical support phone number listed on the back cover for further technical assistance or to locate a qualified service agent in your area. Possible causes - check/repair displayed fault/alert message • the water heater’s control system is polarity sensitive an...

  • Page 54

    54 fault and alert messages (cont) call the technical support phone number listed on the back cover for further technical assistance or to locate a qualified service agent in your area. Possible causes - check/repair displayed fault/alert message • the control system has detected the blower prover s...

  • Page 55

    55 this warranty is applicable to the original owner only. If the glass lined tank in this water heater shall prove upon examination by (the warrantor) to have leaked during the warranty period in normal residential use, due to natural corrosion from potable water therein, the warrantor will furnish...

  • Page 56

    Www.Hotwater.Com 500 tennessee waltz parkway, ashland city, tn 37015 tech support: 800-527-1953 parts: 800-433-2545 copyright © 2013 a. O. Smith water heater company, all rights reserved..