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 100304526_2000545240       _Rev. 01 

www.hotwater       .com 

51

 ANODE ROD MAINTENANCE

• Avoid water heater damage.
• Inspection and replacement of anode rod required.

Property Damage Hazard

CAUTION

The anode rod is a sacrificial metal rod that helps avoid 
corrosion and premature failure (leaks) in the tank. The 
anode rod is a consumable item. Inspect the anode rod 
after the first six months of operation when you drain and 
flush the tank. Replace the anode rod if it is substantially 
worn out or depleted (see Figure 55). Thereafter, inspect 
the anode rod annually or more frequently if needed. If 
you  use  a  water  softener,  your  anode  rod  will  deplete 
faster than normal. Inspect the anode rod more frequently, 
replacing the anode rod if it is depleted. Once the anode 
rod is depleted, the tank will start to corrode, eventually 
developing a leak. Obtain a new anode rod from your local 
plumbing supplier or have a qualified person replace it. 
(Anode rods are a consumable item and are not covered 
under warranty).

Certain water conditions will cause a reaction between the 
anode rod and the water. The most common complaint 
associated  with  the  anode  rod  is  a  “rotten  egg  smell” 
produced  from  the  presence  of  hydrogen  sulfide  gas 
dissolved  in  the  water.  The  removal  of  the  anode  rod 
requires a 1-1/16” socket.

Important:

  Do  not  operate  the  water  heater  without  a 

functioning  anode  rod  as  this  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 equipment from a water conditioning company to 
successfully eliminate all water  odor problems.

To replace the anode:
1.   Turn “OFF” the electrical supply to the water heater.
2.   Turn “OFF” the gas supply at the Main Gas shut-off 

Valve.

3.  CLOSE the cold-water inlet valve to the water heater.
4.  OPEN a nearby hot-water faucet and leave open to 

allow for draining.

5.  Drain approximately  5 gallons  of water from tank. (Refer 

to  "Draining And  Flushing"  for  proper  procedures). 
Close drain valve.

6.  Remove old anode rod.
7.  Use Teflon

®

 tape or approved pipe sealant on threads 

and install new anode rod.

8.  Remove  the  hose  and  follow  instructions  in  the 

"Filling The Water Heater" section.

9.  Follow  the  lighting  instructions  on  the  label  or  see 

"Lighting Instructions" to restart the water heater.

See Figure 56 for anode rod location.

NEW

PARTIALLY DEPLETED

FULLY DEPLETED

Figure 55. 

CAP

ANODE ROD *

* THE ANODE ROD IS COVERED 

BY URETHANE FOAM LOCATED 

UNDER THE CAP. CHIP AWAY 

THE FOAM TO EXPOSE THE 

TOP OF THE ANODE ROD 

Figure 56. 

Summary of Contents for 300 Series

Page 1: ...Y QUESTIONS SHOULD BE DIRECTED TO THE LOCAL DEALER FROM WHOM THE WATER HEATER WAS PURCHASED IF YOU ARE UNSUCCESSFUL PLEASE CONTACT THE COMPANY LISTED ON THE RATING PLATE ON THE WATER HEATER SERIES 300...

Page 2: ...e Wall 25 Termination Types 26 Side Wall Vent Termination Standard 26 Roof Vent Termination Standard 26 Side Wall Vent option For Cold Climates 27 Deluxe Horizontal Venting Kit 28 Pyramid Vent Termina...

Page 3: ...This product is certified to comply with a maximum weighted average of 0 25 lead content as required in some areas IMPORTANT DEFINITIONS Qualified Installer A qualified installer must have ability eq...

Page 4: ...expose water heater control to excessive gas pressure Use only gas shown on rating plate Maintain required clearances to combustibles Keep ignition sources away from faucets after extended period of n...

Page 5: ...aged For operation above 10 100 a high altitude orifice must be installed Do not operate if soot buildup is present Do not obstruct water heater air intake with insulating jacket Do not obstruct blowe...

Page 6: ...t follow safety rules the water heater will not operate properly It could cause DEATH SERIOUS BODILY INJURYAND OR PROPERTY DAMAGE This manual contains instructions for installation operation and main...

Page 7: ...imum height of eight 8 feet above grade directly in line with the exhaust vent terminal for the horizontally vented gas fueled heating appliance or equipment The sign shall read in print size no less...

Page 8: ...T WATER OUT MASSACHUSETTS INSTALLATION REQUIREMENTS 1 CONNECT ELECTRONICALLY CONTROLLED TIMER TO AN ALL BRONZE PUMP PUMP MUST ACTIVATE EVERY 6 HOURS FOR 60 SECONDS TURN PUMP TIMER OFF BEFORE CLOSING P...

Page 9: ...er Coupling see Figure 5 27 Gear Clamp see Figure 5 28 Blower with Power Cord see Figure 5 29 Air Duct Adapter 30 Air Inlet Snorkel 31 Air Duct 32 Thermal Expansion Tank see Closed Water Systems and T...

Page 10: ...ss has 120 VAC during operation See Vent Pipe Installation for more information The orifice on Natural gas models has Right hand thread the orifice on Propane LP models has Left hand thread For Natura...

Page 11: ...N MODELS ARE EQUIPPED WITH SIDE PLUMBING CONNECTIONS FOR SPACE HEATING THE HOT AND COLD FITTING ASSEMBLIES PART 100108524 CAN BE ORDERED THROUGH THE MANUFACTURER Figure 7 This appliance has been desig...

Page 12: ...alvesareavailableatplumbingsupplystores Consult a Qualified Installer or ServiceAgency Follow mixing valve manufacturer s instructions for installation of the valves Before changing the factory settin...

Page 13: ...o purge the water lines of air and sediment and to ensure complete filling of the tank The electrical power may then be turned on Verify proper operation after servicing See also Installation Checklis...

Page 14: ...on of the water heater 3 Avoid locations that could cause the water heater to freeze from outside air 4 Selected location must provide access to a properly grounded electrical branch circuit A dedicat...

Page 15: ...ervicing When installing the heater consideration must be given to proper location Location selected should be as close to the wall as practicable and as centralized with the water piping system as po...

Page 16: ...wed to collect and freeze Pooling of condensate can restrict airflow and can cause nuisance failures of the system INSULATION BLANKETS Insulation blankets are available to the general public for exter...

Page 17: ...of valves Before changing the factory setting on thermostat read Operating The Temperature Control System section in this manual This water heater should not be connected to any heating systems or com...

Page 18: ...d water line an expansion tank of adequate size must be installed 8 Combo Heating Systems require higher water temperatures than other applications When the system is used to supply water for Combo He...

Page 19: ...on tank should be installed on all closed systems to control the harmful effects of thermal expansion Contact a plumbing service agency or your retail supplier regarding the installation of a thermal...

Page 20: ...xcessive length over 30 or use of more than four elbows can cause restriction and reduce the discharge capacity of the valve No valve or other obstruction is to be placed between the T P valve and the...

Page 21: ...t water outlet and cold water inlet pipes to the water heater 4 Locate the slit running the length of a section of pipe insulation 5 Spread the slit open and slip the insulation over the cold water in...

Page 22: ...e dry Use joint compound or tape compatible with natural gas and propane Leak test before operating heater Disconnect gas piping and shut off valve before pressure testing system Fire and Explosion Ha...

Page 23: ...ss it is completely full of 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 To fill the water...

Page 24: ...of the vent pipe system is mandatory for the safe and efficient operation of this water heater and is an important factor in the life of the unit VENT KIT A Vent Kit included with this water heater ma...

Page 25: ...or the combustion air inlet to any other appliance 6 in for appliances 10 000 BTUh 3 kW 9 in for appliances 10 000 BTUh 3 kW and 50 000 BTUh 15 kW 12 in for appliances 50 000 BTUh 15 kW C to window o...

Page 26: ...izontal centerline of the air intake terminal may not be located more than 24 below the horizontal centerline of the exhaust vent terminal 4 To avoid exhaust recirculation the air intake terminal may...

Page 27: ...y be 90 elbows if specified by local requirements Note The vertical centerline of the air intake termination and the vertical centerline of the exhaust vent termination must not be closer than 8 Impor...

Page 28: ...ermination It might be necessary to trim the vent to suit the height of the new water heater For the purpose of these installations the calculations for equivalent length will refer to the distance fr...

Page 29: ...100304526_2000545240_Rev 01 www hotwater com 29 3 VENT PIPING INTAKE 3 VENT PIPING EXHAUST O RING SCREW VENT PIPING Figure 28...

Page 30: ...nd distance between hole centers can be found in Table 2 2 Slide both the intake and exhaust pipes through the holes Solvent cement both pipes to the base of the vent termination kit follow the solven...

Page 31: ...in a vertical roof installation Ensure the combustion air intake location is above the anticipated snow level VENT DIA P N 2 100112869 3 100111100 Table 3 STRAP FIELD SUPPLIED COMBUSTION AIR COMBUSTI...

Page 32: ...ulation see Figure 35 When more than 2 kits are installed only 2 of them shall be less than 9 5 apart Never install 3 termination kits together less than 9 5 apart see Figure 36 9 5 MAX OR 43 5 MIN WA...

Page 33: ...over 20 a debris vent screen must be used see Figure 41 12 MIN APPLY SEALANT TO BOTH SIDES OF WALL VENT SCREEN INSTALL IN TERMINATIONS OR 12 ABOVE ANTICIPATED SNOW LEVEL TEE FITTING EXHAUST TERMINATIO...

Page 34: ...al wall plates that fit the polypropylene venting are also available through your supplier 1 Carefully inspect the entire venting system for any signs of cracks or fractures particularly at joints bet...

Page 35: ...5 elbow to direct the vent pipe downward unless otherwise specified by local requirements 3 If additional elbows are used in the vent system the allowable vent lengths are reduced 4 Two 45 elbows are...

Page 36: ...r next to the blower In freezing weather it is recommended to locate the restrictive screens next to the blower to reduce the potential for frost buildup on the intake screen Install the appropriate r...

Page 37: ...ntake vent system is located at the blower this joint should not be cemented but secured with a screw to allow servicing see Figure 47 through Figure 49 Vent Pipe Runs 1 The exhaust vent system must n...

Page 38: ...characteristics etc Insertion Tool Helpful for larger diameter pipe and fittings 6 and above Read instruction manual before installing using or servicing water heater Do not store or use gasoline or...

Page 39: ...f the fitting socket When this happens a sufficient quantity of cement must be applied to the joint to fill the gap between the pipe and fitting The gap must be filled to obtain a strong leak free joi...

Page 40: ...Figure 47 through Figure 49 5 This water heater is a polarity sensitive appliance and will not operate if the power supply polarity is reversed Power to this water heater must be wired properly corre...

Page 41: ...ent piping is firmly secured in the coupling and is gas tight Do not over tighten or cause distortion of any of the parts Ensure the bottom of the rubber coupling is firmly seated on the blower outlet...

Page 42: ...at least halfway prior to operating the heater Ensure the end of the tube has access to a drain as condensate will flow from the end Secure the tubing to the side of the heater Caution must be used t...

Page 43: ...f approved material Acceptable size length and number of elbows on exhaust vent system Installed in accordance with prevailing provisions of local codes or in the absence of such the latest edition of...

Page 44: ...ch on the control to the OFF position 5 Do not attempt to light manually 6 Wait five 5 minutes to clear out any gas If you then smell gas STOP Follow B in the safety information above on this label If...

Page 45: ...firm or physically mentally handicapped If anyone using hot water fits into one of these groups or if there is a local code or state law requiring certain temperature water at the hot water tap then y...

Page 46: ...than 5 seconds A 130 More than 30 seconds HOT 120 More than 5 minutes LOW 110 Normal shower temp VAC 70 N A Table 9 Note The temperatures indicated are approximate The actual temperature of the heated...

Page 47: ...s and should be considered normal OPERATIONAL CONDITIONS Smelly Water Each water heater contains at least one anode rod for corrosion protection of the tank Certain water conditions will cause a react...

Page 48: ...ich could cause improper venting or leakage of combustion products Be sure the vent piping is properly connected to prevent escape of dangerous flue gases which could cause deadly asphyxiation Obstruc...

Page 49: ...2 that water discharge will not cause any property damage as water may be extremely hot Use care when operating valve as the valve may be hot To check the relief valve lift lever at the end of valve...

Page 50: ...to help the water in the tank drain faster 8 If a large amount of sediment was present when the tank was drained follow instructions in the To Flush The Water Heater Storage Tank section 9 Close the w...

Page 51: ...ulfide gas dissolved in the water The removal of the anode rod requires a 1 1 16 socket Important Do not operate the water heater without a functioning anode rod as this will void any warranties A spe...

Page 52: ...high water pressure in your area E The temperature pressure relief valve may be leaking at the tank fitting F Water from a drain valve may be due to the valve being slightly opened G The drain valve m...

Page 53: ...t Snorkel 31 Air Duct 33 Flame Sensor Rod see Figure 3 Figure 4 see also Figure 60 Figure 61 34 Sheet Metal Burner see Figure 3 Figure 4 see also Figure 60 Figure 61 35 Gas Orifice see Figure 3 Figure...

Page 54: ...wn with Junction Box Cover removed for clarity 43 46 27 45 Figure 62 Notes Items not supplied with the water heater The side recirculation loop connections may not be used as the primary water inlet a...

Page 55: ...tch to the OFF position Wait for 10 seconds and move the switch back to the ON position If the problem that caused the control to lock out has not been corrected the control will remain or again go ba...

Page 56: ...7 Six One Flash three second pause Soft Lockout Retry Limit Failed Trial For Ignition 8 Six Two Flash three second pause Soft Lockout Recycle Limit Pressure Switch High Limit opened 9 Six Three Flash...

Page 57: ...Ensure the air pressure sensing tubes are properly connected and not kinked or damaged 3 Check continuity of the vent temperature limit switch replace switch if contact remain open 4 Check continuity...

Page 58: ...d air intake pipes 7 If there are excessive restrictions in the air intake pipe the air pressure switch N C will open 8 Check air pressure switch performance Check blower vacuum with a manometer Compa...

Page 59: ...ailure to install the proper vent screens 2 Closed water system 3 Pressure build up 4 Improperly seated valve 1 Ensure the correct size of exhaust and air intake pipes were used per the instruction ma...

Page 60: ...500 Tennessee Waltz Parkway Ashland City TN 37015 Technical Support 800 527 1953 Parts 800 433 2545 Fax 800 644 9306 www hotwater com Copyright 2018 A O Smith Corporation All rights reserved...

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