A.O. Smith GDHE-50 Instruction Manual Download Page 10

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* CAUTION HARNESS HAS 120 VAC. IN OPERATION.
** See Planning the Vent System, Installation of Vent System and Condensate Piping for more information.

Figure 1B: 50 GALLON UNIT

VACUUM RELIEF

VALVE

*INSTALL PER

LOCAL CODES

50 GALLON UNIT

FEATURES AND COMPONENTS

**29

26, 27

34 (SEE

ACCESS

PANEL

CAUTION)

**14

**15

Caution:

This access panel covers

a 2” NPT plug that was required

during the manufacturing of this

water heater. This 2” NPT flange is

not a cleanout fitting

, removing the

2” NPT plug and using this fitting as

a cleanout could void your warranty.

ACCESS PANEL

Summary of Contents for GDHE-50

Page 1: ... 131 ALL TECHNICAL AND WARRANTY QUESTIONS SHOULD BE DIRECTED TO THE LOCAL DEALER FROM WHOM THE WATER HEATER WAS PURCHASED IF YOU ARE UNSUCCESSFUL CALL THE TECHNICAL SUPPORT PHONE NUMBER SHOWN ON THE WATER HEATER LABELING RESIDENTIAL GAS WATER HEATERS For Your Safety AN ODORANT IS ADDED TO THE GAS USED BY THIS WATER HEATER Ashland City TN 37015 www hotwater com Thank you for buying this energy effi...

Page 2: ...ef Valve 22 Condensate Piping 23 High Altitude Installations 23 Filling The Water Heater 23 INSTALLATION REQUIREMENTS FOR THE COMMONWEALTH OF MASSACHUSETTS 24 VENTING INSTALLATION 25 Vent Installation Considerations 25 Polypropylene Installations 26 Vent Pipe Termination 27 Planning The Vent System 27 Installation Of Horizontal Through The Wall Vent System 27 Direct Vent Terminal Installation 28 I...

Page 3: ...birth defects or other reproductive harm and requires businesses to warn of potential exposure to such substances This product contains a chemical known to the State of California to cause cancer birth defects or other reproductive harm This water heater can cause low level exposure to some of the substances listed in the Act DANGER WARNING CAUTION CAUTION DANGER indicates an imminently hazardous ...

Page 4: ...using any electrical appliance connected to the hot water system If hydrogen is present there will probably be an unusual sound such as air escaping through the pipe as the water begins to flow THERE SHOULD BE NO SMOKING OR OPEN FLAME NEAR THE FAUCET AT THE TIME IT IS OPEN Read and understand this instruction manual and the safety messages herein before installing operating or servicing this water...

Page 5: ...5 GENERAL SAFETY INFORMATION ...

Page 6: ...ead and understand instruction manual Breathing Hazard Carbon Monoxide Gas Property Damage Hazard All water heaters eventually leak Do not install without adequate drainage CAUTION Fire and Explosion Hazard Leak test before placing the water heater in operation Disconnect gas piping and main gas shutoff valve before leak testing Install sediment trap in accordance with NFPA 54 Use joint compound o...

Page 7: ...the water heater and your safety Detailed installation diagrams are also found in this manual These diagrams will serve to provide the installer with a reference It is essential that all venting water piping gas piping and wiring be installed as shown Particular attention should be given to the installation of thermometers at the locations indicated in the piping diagrams as these are necessary fo...

Page 8: ...IT Table 1 ROUGH IN DIMENSIONS Units A B C D E F G H I 50G 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 75G Inches 64 71 45 64 27 75 16 00 3 71 8 00 7 93 57 36 58 98 cm 164 4 115 9 70 5 40 6 9 4 20 3 20 1 145 7 149 8 Top Inlet and Outlet 50G 3 4 NPT 75G 1 NPT Side Inlet and Outlet 3 4 NPT Gas Inlet 1 2 NPT ...

Page 9: ...pply Pressure for Natural Gas 3 50 87kPa Minimum Supply Pressure for Propane Gas 8 00 1 99kPa Minimum pressure must be maintained under both load and no load dynamic and static conditions Table 3 RECOVERY CAPACITIES Recovery capacity based on 96 thermal efficiency Input Recovery Capacities Rating Btu hr Rating kW Temp Rise F 30 40 50 60 70 80 90 100 110 120 130 140 C 17 22 28 33 39 44 50 56 61 67 ...

Page 10: ... CODES 50 GALLON UNIT FEATURES AND COMPONENTS 24 18 35 31 9 4 2 3 19 29 20 22 23 21 1 12 16 25 11 17 33 13 26 27 34 SEE ACCESS PANEL CAUTION 28 30 32 21 18 5 14 15 Caution Thisaccesspanelcovers a 2 NPT plug that was required during the manufacturing of this water heater This 2 NPT flange is notacleanoutfitting removingthe 2 NPT plug and using this fitting as acleanout could void your warranty ACCE...

Page 11: ...nstallation of Vent System and Condensate Piping for more information VACUUM RELIEF VALVE INSTALL PER LOCAL CODES 75 GALLON UNIT FEATURES AND COMPONENTS CONT 24 18 35 31 9 4 2 3 19 22 23 21 1 12 17 25 11 29 5 18 21 20 16 26 27 28 34 30 32 Figure 1C 75 GALLON UNIT 14 15 33 13 ...

Page 12: ...y Board 12 Top Plastic Enclosure 13 Display Enclosure 14 Exhaust Elbow Assembly 15 Condensate Tubing 16 Off On Switch 17 Display Label 18 Hot Water Outlet 19 Gas Supply 20 Main Manual Gas Shutoff Valve 21 Union 22 Inlet Water Shutoff Valve 23 Cold Water Inlet 24 Inlet Dip Tube 25 T P Relief Valve 26 Rating Plate 27 Labels 28 Drain Valve 29 Vent Terminal 30 Drain Pan 31 Anode Rod 32 Insulation 33 T...

Page 13: ...ed to flow freely from the exhaust elbow and for obstructions in the exhaust venting and exhaust vent terminal Also verify that the vent length does not exceed the maximum allowed as shown in the Vent Section of this manual BLOCKED INTAKE SWITCH The Blocked Intake Switch is set up to shut the unit off when a build up of negative pressure in the intake air pipe occurs This switch is a negative pres...

Page 14: ...ter where an adequate supply of fresh air for combustion and ventilation can be obtained See Combustion Air and Ventilation on Page 15 9 Locate the water heater where the vent and intake air piping when installed will remain within the maximum equivalent lengths allowed See Venting on Page 25 10 Do not locate the water heater where noise such as the Combustion Blower during normal operation will b...

Page 15: ... proper combustion potentially resulting in fire asphyxiation serious personal injury or death Do not apply insulation to the top of the water heater as this will interfere with safe operation of the blower assembly Do not cover the control system LCD on top of the water heater Do not cover the outer door thermostat or temperature pressure relief valve Do not cover the instruction manual Keep it o...

Page 16: ...ings to provide fresh air must be provided that accommodate the requirements for all appliances in the room and the exhaust fan Undersized openings will cause air to be drawn into the room through the water heater s vent system causing poor combustion Sooting serious damage to the water heater and the risk of fire or explosion may result It can also create a risk of asphyxiation LOUVERS AND GRILLE...

Page 17: ...f the bottom of the enclosure The horizontal ducts shall communicate directly with the outdoors See Figure 7 Each duct opening shall have a minimum free area of 1 square inch per 2 000 Btu hr 1100 mm2 per kW of the aggregate input rating of all appliances installed in the enclosure When ducts are used they shall be of the same cross sectional area as the free area of the openings to which they con...

Page 18: ...ualified Installer or Service Agency Follow manufacturer s instructions for installation of the valves Before changing the factory setting on the thermostat read theTemperature Regulation section in this manual 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...

Page 19: ...ormal shower temp 116 46 7 pain threshold 116 46 7 35 minutes 45 minutes 122 50 1 minute 5 minutes 131 55 5 seconds 25 seconds 140 60 2 seconds 5 seconds 149 65 1 second 2 seconds 154 67 8 instantaneous 1 second U S Government Memorandum C P S C Peter L Armstrong Sept 15 1978 GAS PIPING Make sure gas supplied is same type listed on model rating plate The inlet gas pressure must not exceed 14 inch ...

Page 20: ...aximum gas supply pressure limit of 14 W C 3 48 kPa The maximum supply pressure is measured while gas is not flowing static pressure AND while gas is flowing dynamic pressure SUPPLY GAS REGULATOR The maximum allowable gas supply pressure for this water heater is 14 inches W C 3 5 kPa Install a positive lock up gas pressure regulator in the gas supply line if inlet gas pressure can exceed 14 inches...

Page 21: ...h as pressure reducing valves check valves and back flow preventers Devices such as these cause the water system to be a closed system THERMAL EXPANSION As water is heated it expands thermal expansion In a closed system the volume of water will grow when it is heated As the volume of water grows there will be a corresponding increase in water pressure due to thermal expansion Thermal expansion can...

Page 22: ...equipment of materials as meeting the requirements for Relief Valves for Hot Water Supply Systems ANSI Z21 22 CSA 4 4 and the code requirements of ASME If replaced the new T P valve must meet the requirements of local codes but not less than a combination Temperature Pressure Relief Valve rated sized and certified as indicated in the above paragraph The new valve must be marked with a maximum set ...

Page 23: ... copper tubing iron or steel pipe for the condensate drain line Condensate drain lines should be installed in conditioned areas only Drain lines installed in areas that are subject to freezing temperatures should be wrapped with a nationally recognized listed heat tape and or approved insulation for freeze protection Install per manufacturer s instructions Do not common drain with the temperature ...

Page 24: ...the horizontally vented gas fueled heating appliance or equipment The sign should read in print size no less than one half 1 2 inch in size GAS VENT DIRECTLY BELOW KEEP CLEAR OF ALL OBSTRUCTIONS INSPECTION The state or local gas inspector of the side wall horizontally vented gas fueled equipment should not approve the installation unless upon inspection the inspector observes carbon monoxide detec...

Page 25: ...PVC DWV fittings meeting ASTM D 2665 Use CPVC fittings ASTM F 438 for CPVC pipe and ABS fittings ASTM D 2661 3311 for ABS pipe If CPVC or ABS pipe and fittings are used then proper cement must be used for all joints including joining the pipe to Termination PVC Material If Polypropylene pipe and fittings are used the metal joint connector rings available from the Polypropylene vent manufacturer mu...

Page 26: ... Pipe Diameter Flue Outlet Adapter Adapter Connector Ring Connector 90 Degree Elbow Vent Material Terminal s 2 2PPS AD PPS PAC 2PPS LB 2PPS E90 2PPS 2PPS 2PPS BG for Exhaust 2PPS E90 2PPS BG for Intake Direct Vent only 3 3PPS AD PPS PAC 3PPS LB 3PPS E90 3PPS 3PPS 3PPS BG for Exhaust 3PPS E90 3PPS BG for Intake Direct Vent only Polypropylene vent systems do not use cement to connect the pipe and el...

Page 27: ...ION The first step is to determine where the vent pipe will terminate See Figures 12 Figure 13A and Figure 14 The vent may terminate through a sidewall as shown in Figure 12 and Figure 14 or through the roof as shown in Figure 15 and Figure 16 The vent system must terminate so that proper clearances are maintained as cited in local codes or the current edition of the National Fuel Gas Code ANSI Z2...

Page 28: ...now be positioned on the outside wall using the drilled holes as a centering point for the template A MASONRY SIDE WALLS Chisel an opening approximately 1 2 1 3 cm larger than the marked circle B WOODEN SIDE WALLS Drill a pilot hole approximately one quarter inch outside of the marked circle This pilot hole is used as a starting point for a saws all or sabre saw blade Cut around the marked circle ...

Page 29: ...hanical air supply inlet into building or combustion air inlet to any other appliance 4 feet 1 2 m below or to side of opening 1 foot 30 cm above opening D Vertical clearance to ventilated soffit located above the terminal within a horizontal distance of 2 feet 61 cm from the center line of the terminal 12 inches 30 cm K Clearance to a mechanical air supply inlet 3 feet 91 cm above if within 10 fe...

Page 30: ... mechanical air supply inlet into building or combustion air inlet to any other appliance 6 inches 15 cm for appliances up to 10 000 Btu hr 3 kW 9 inches 23 cm for appliances between 10 000 Btu hr 3 kW and 50 000 Btu hr 15 kW 12 inches 30 cm for appliances above 50 000 Btu hr 15 kW D Vertical clearance to ventilated soffit located above the terminal within a horizontal distance of 2 feet 61 cm fro...

Page 31: ...hing 3 The air intake termination and the exhaust vent termination must penetrate the same side of roof 4 The center line of the air intake termination and the center line of the exhaust vent termination must be no closer than 24 61cm See Figure 17 and Figure 18 FLAT ROOF INSTALLATION On flat roof installations the air intake and the exhaust vent terminations must be a minimum of 24 inches 60 cm a...

Page 32: ...VE 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 Figure 20 Figure 22 Figure 23 Figure 21 DIRECT VENT DIAGRAM ...

Page 33: ...eration INSTALLATION VERTICAL ROOF TERMINATION 1 Determine best location for termination kit NOTE Roof termination is preferred since it is less susceptible to damage has reduced chances to intake contaminants and less visible vent vapors 2 Cut 1 hole 5 in diameter 3 Partially assemble concentric vent termination kit a Cement Y concentric fitting to larger diameter kit pipe see Figure 24 b Cement ...

Page 34: ...tioned where the vent vapors will not damage plants shrubs or air conditioning equipment Termination kit positioned so it will not be affected by wind eddy that may allow recirculation of combustion products or airborne leaves or light snow Termination kit positioned where it will not get damaged or be subjected to foreign objects such as stones balls etc Termination kit positioned where the vent ...

Page 35: ...ore than 60 1 5 m See Figure 24 Do not use field supplied couplings to extend pipes Airflow restriction will occur and the heater pressure switch may cause intermittent operation 7 Cement heater combustion air and vent pipes to concentric vent termination assembly See Figure 29 for proper pipe attachment 8 Operate heater through 1 heat cycle to ensure combustion air and vent pipes are properly con...

Page 36: ...plate 4 Screw the Cap to the Base using the supplied screws 5 Once the vent termination and pipes are secured the wall penetrations will need to be sealed from the interior using a PVC compatible sealant material 6 All vent pipes and air inlets must terminate at the same height to avoid possibility of severe personal injury death or substantial property damage 8 Operate heater through 1 heat cycle...

Page 37: ...37 LIGHTING AND OPERATION LABELS ...

Page 38: ...pply to the water heater must be turned off and on again to reset the control system Contact your dealer or servicer if continued high limit switch operation occurs It is recommended that lower water temperatures be used to avoid the risk of scalding It is further recommended in all cases that the water temperatures be set for the lowest temperature which satisfies your hot water needs This will a...

Page 39: ...ystem The Combustion Blower Igniter and the 24 Volt Gas Control Valve are all energized by the control system The main components of the control system are a UIM user interface module and a CCB central control board The UIM is located on the top front side of the water heater The CCB is mounted on top of the water heater inside a protective enclosure CONTROL SYSTEM NAVIGATION All operational infor...

Page 40: ...stion Blower is being energized The Blower Prover pressure switch contacts have closed The check mark icon is visual confirmation of contact closure The Igniter is being energized GAS OFF O N The 24 Volt Gas Control Valve is being energized The control system has sensed flame at the Main Burner from the Flame Sensor The control system has declared a Fault condition and must be inspected serviced b...

Page 41: ...ion that caused the Fault has not been corrected Heating Disabled The heating is disabled by the Enable Disable On Off switch in front of the unit CONTROL SYSTEM MENUS From the Desktop screen pressing the Operational button directly below Menu on the LCD will display the Main Menu This is where all control system menus are located The table below describes the control system menus Table 14 CONTROL...

Page 42: ...nd description of control system menus Use the Up and Down Buttons to view all control system menus from the Main Menu With Temperatures menu selected highlighted in black in the Main Menu screen press the Operational Button under SELECT to enter the Temperatures menu If the Temperatures menu is not selected use the Up and Down Buttons to select this menu item Temperatures Heater Status Display Se...

Page 43: ...ries greatly from the Operating Set Point setting These settings are adjusted in the same way described for the Operating Set Point and Differential Adjustment Operating Set Point 140 F Differential 8 F Tank Probe Offset 0 F CHANGE BACK HELP Temperatures HEATER STATUS DESCRIPTION ACTION DISPLAY Select Heater Status from the Main Menu and press the Operational Button under SELECT to enter this menu...

Page 44: ...umulated time the control system has been in the heating operating state burner run time Total Cycle Count Total accumulated count of heating cycles Config CRC A number associated with the configuration data CCB Version Software version for central control board UIM Version Software version for user interface module NOTE Historical data is stored in the CCB s memory If this CCB is replaced during ...

Page 45: ... event will replace the oldest Press the Operational Button under VIEW to view details for each Fault or Alert message stored NOTE fault history memory is cleared after 30 days 1 Blocked Air Intake A7 51 mins ago 2 Blocked Exhaust A8 54 mins ago 3 Low Gas Pressure A6 57 mins ago 4 Blower Prover Failure AC VIEW BACK HELP Fault History FAULT OCCURRENCE DESCRIPTION ACTION DISPLAY Select Fault Occurre...

Page 46: ...em Show Contact Information Yes Change Contact Name Change Contact Phone Current Contact Info 000 000 0000 Access Code UPDATE CANCEL Service Contact Information Using the UP and DOWN buttons select highlighted in black the Change Contact Name menu item Press the Operational Button under SELECT to open the Change Contact Name menu Show Contact Information Yes Change Contact Name Change Contact Phon...

Page 47: ...ditions will cause a reaction between this rod and the water The most common complaint associated with the anode rod is one of a rotten egg smell in the hot water The smell is a result of four factors which must all be present for the odor to develop a A concentration of sulfate in the supply water b Little or no dissolved oxygen in the water c A sulfate reducing bacteria which has accumulated wit...

Page 48: ...ociated with the anode rod is a rotten egg smell produced from the presence of hydrogen sulfide gas dissolved in the water IMPORTANT Do not remove this rod permanently as it will void any warranties A special anode rod may be available if water odor or discoloration occurs NOTE This rod may reduce but not eliminate water odor problems The water supply system may require special filtration equipmen...

Page 49: ...ining And Flushing on Page 49 Replace the Temperature Pressure Relief Valve with a properly rated sized new one see Temperature Pressure Relief Valve on Page 22 for instructions on replacement DISCHARGE PIPE TEMPERATURE PRESSURE RELIEF VALVE Figure 37 If the Temperature Pressure Relief Valve on the water heater weeps or discharges periodically this may be due to thermal expansion NOTE Excessive wa...

Page 50: ...e and terminate it to an adequate drain 5 Ensure the drain hose is secured before and during the entire flushing procedure Flushing is performed with system water pressure applied to the water heater 6 Open the water heater drain valve to flush the storage tank 7 Flush the water heater storage tank to remove sediment and allow the water to flow until it runs clean 8 Close the water heater drain va...

Page 51: ...itting G Leakage from recirculation plug or pipe connection H Leakage from the plug under the cleanout cover I Leakage from the temperature probe connection Not shown in figure J Condensate from the exhaust connection Leakage from other water heaters water lines or ground seepage should also be checked To check where threaded portion enters tank insert cotton swab between jacket opening and fittin...

Page 52: ...e cycle to purge the water heater of all combustion gases When the post purge cycle is complete the blower is de energized and will coast to a stop 12 The control system now enters the standby mode while continuing to monitor the internal storage tank water temperature and the state of other system devices If the tank temperature drops below the Operating Set Point minus the Differential setting t...

Page 53: ...cle is activated Blower Prover switch contacts confirmed closed by control system Igniter is energized 24 V Gas Valve is energized gas flows to Main Burner Is flame sensed at the Main Burner control system monitors the flame sensor Control System Locks Out Displays Fault Msg NO Control System Locks Out Blower Prover Open Fault Msg is displayed NO Combustion Blower is energized Pre Purge cycle Cont...

Page 54: ...he water heater Refer to the parts list for more information or call the parts department or technical support phone number listed on the back cover of this manual for further assistance OPERATIONAL PROBLEMS Read and understand this instruction manual and the safety messages herein before installing operating or servicing this water heater Failure to follow these instructions and safety messages c...

Page 55: ...CONDITIONS When the control system declares an Alert condition it will display an Alert message on the control system s LCD with a question mark The water heater will continue to operate during an Alert condition but the water heater must be serviced by a qualified service technician as soon as possible RESETTING CONTROL SYSTEM LOCK OUTS To reset the control system from a lock out condition turn o...

Page 56: ... CHANGE BACK ADVANCED Ignition Failure Fault occurred 2 mins ago The water heater has failed to ignite the burner Call a service professional Your Company Name Here press DOWN for more The control system has detected the Blocked Exhaust Switch contacts are open The condensate drain is blocked filling the exhaust elbow with water clear the condensate drain Loose or open wiring to the Blocked Exhaus...

Page 57: ...e Blocked Intake Air Switch contacts are open Loose or open wiring to the Blocked Intake Air Switch Excessive equivalent pipe length exceeded the maximum number of 90 elbows or wrong pipe size used in the intake air piping system Excessive negative air pressure in the installed space CHANGE BACK ADVANCED Blocked Air Intake Fault occurred 2 mins ago The combustion air intake is restricted Call a se...

Page 58: ...LABEL ALL WIRES PRIOR TO DISCONNECTION WHEN SERVICING CONTROLS WIRING ERRORS CAN CAUSE IMPROPER AND DANGEROUS OPERATION VERIFY PROPER OPERATION AFTER SERVICING Figure 40 POWER VENT WIRING SCHEMATIC WIRING DIAGRAM ...

Page 59: ...any operation of it in a modified form or any attempt to repair tank leaks or parts will void this warranty SERVICE AND LABOR RESPONSIBILITY UNDER THIS LIMITED WARRANTY THE WARRANTOR WILL PROVIDE ONLY A REPLACEMENT WATER HEATER OR PART THEREOF THEOWNERISRESPONSIBLEFORALLOTHERCOSTS Such costs may include but are not limited to a Labor charges for service removal or reinstallation of the water heate...

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A.O. Smith GDHE-50, Instruction Manual

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