A.O. Smith 305 Operation & Installation Manual Download Page 17

 

 

305, 505, 705 Indoor Manual 

17 

The freeze protection features include electrical 
heating elements and intermittent firing of the burner.  
Freeze protection may be disabled if electricity or gas 
is not supplied, or if there is an error preventing the 
water heater from functioning.  Loss of freeze 
protection may result in water damage from a burst 
heat exchanger or water lines. 

The installation of auto drain down solenoid valves is 
optional.  However, it is strongly recommended that 
these valves be installed to prevent damage from 
freezing in case the normal freeze protection should 
become disabled.  Any product damage due to 
freezing will not be covered by the warranty. 

In addition, the solenoid valves should be connected 
electrically to a sub-PC board that attaches to the PC 
board in the unit.  This allows the solenoid valves to 
operate if the water heater is disabled due to an error 
code.   

The solenoid valves and sub-PC board are available 
for purchase separately. 

 

 

Freeze Protection 

  

Water 

Piping 

        

                       

• 

A manual water control valve must be placed in the 
water inlet connection to the water heater before it is 
connected to the water line.  Unions may be used 
on both the hot and cold water lines for future 
servicing and disconnection of the unit. 

• 

The piping (including soldering materials) and 
components connected to this appliance must be 
approved for use in potable water systems. 

• 

Purge the water line to remove all debris and air.  
Debris will damage the water heater. 

• 

Toxic chemicals such as those used for boiler water 
treatment are not to be introduced to the potable 
water used for space heating. 

• 

If the appliance will be used as a potable water 
source, it must not be connected to a system that 
was previously used with a nonpotable water 
heating appliance. 

• 

Ensure that the water filter on the water heater is 
clean and installed. 

• 

An approved pressure relief valve is required by the 

American National Standard (ANSI Z21.10.3) / 
Canadian Standard (CSA 4.3) 

for all water heating 

systems. 

• 

The relief valve must comply with the standard for 

Relief Valves and Automatic Gas Shutoff Devices 
for Hot Water Supply Systems ANSI Z21.22

 and /or 

the standard 

Temperature, Pressure, Temperature 

and Pressure Relief Valves and Vacuum Relief 
Valves, CAN1-4.4

.   

• 

The relief valve must be rated up to 150 psi and to 
at least the maximum BTU/hr of the appliance. 

• 

The discharge from the pressure relief valve should 
be piped to the ground or into a drain system to 
prevent exposure or possible burn hazards to 
humans or other plant or animal life.  Follow local 
codes.  Water discharged from the relief valve could 
cause severe burns instantly, scalds, or death. 

• 

The pressure relief valve must be manually 
operated once a year to check for correct operation. 

• 

The relief valve should be added to the hot water 
outlet line according to the manufacturer’s 
instructions.  DO NOT place any other type valve or 
shut off device between the relief valve and the 
water heater. 

• 

Do not plug the relief valve and do not install any 
reducing fittings or other restrictions in the relief line.  
The relief line should allow for complete drainage of 
the valve and the line. 

• 

If a relief valve discharges periodically, this may be 
due to thermal expansion in a closed water supply 
system.  Contact the water supplier or local 
plumbing inspector on how to correct this situation.  
Do not plug the relief valve. 

• 

Neither this water heater nor the 

American National 

Standard (ANSI Z21.10.3) / Canadian Standard 
(CSA 4.3) 

requires a combination temperature and 

pressure relief valve for this appliance.  However, 
local codes may require a combination temperature 
and pressure relief valve. 

Pressure Relief Valve 

General Instructions 

Summary of Contents for 305

Page 1: ...on and service must be performed by a qualified installer service agency or the gas supplier WARNING If the information in these instructions is not followed exactly a fire or explosion may result causing property damage personal injury or death Operation and Installation Manual INSTALLER Leave this manual with the appliance CONSUMER Retain this manual for future reference Table of Contents 2 Cons...

Page 2: ... Water Heater 14 Electrical Connection 15 Gas Piping General Instructions 15 Pipe Sizing Procedure Example 16 Water Piping General Instructions 17 Pressure Relief Valve 17 Freeze Protection 17 Freeze Protection Piping 18 Recommended Piping for Basic Installation 19 Recommended Piping for Circulation Systems 20 Optional Piping for Circulation Systems 21 Venting Instructions Intake Exhaust Guideline...

Page 3: ... 85º C Maximum Temp Setting Residential 140º F 60º C Minimum Temperature Setting 98º F 37º C Weight 50 lb 23 kg 55 lb 25 kg Efficiency Rating Propane Gas 84 Noise level 49 dB Electrical Consumption Normal 79 W 99 W Standby 2 8 W 2 W Anti frost Protection 100 W 116 W By Pass Control Fixed Minimum Gas Supply Pressure Natural Gas 5 0 inch W C Propane 8 0 inch W C Maximum Gas Supply Pressure Natural G...

Page 4: ...his symbol alerts you to potential hazards that can kill or hurt you and others Indicates an imminently hazardous situation which if not avoided will result in death or serious injury Indicates a potentially hazardous situation which if not avoided could result in death or serious injury Indicates a potentially hazardous situation which if not avoided could result in minor or moderate injury It ma...

Page 5: ... water is constantly monitored This appliance may adjust the water flow in order to maintain the temperature setting The water flow may vary from summer to winter due to the difference in ground water temperature Description of Operation Features Available on Remote Controller The remote controller is supplied with the appliance Dimensions inches 3 5 W x 4 75 H x 0 75 D Operating Instructions Feat...

Page 6: ...re setting for this appliance installed without a remote controller is 120º F 49º C If desired the temperature setting can be changed to 140º F 60º C by adjustment of a dip switch Set dip switch 5 to ON to obtain 140º F water temperature setting Set dip switch 5 to OFF default to obtain 120º F water temperature setting 2 Press the or buttons to obtain the desired temperature setting All hot water ...

Page 7: ...are suggestions only A temperature lower than 98º F 37º C can be obtained at the tap by mixing with cold water To change the temperature scale from Celsius to Fahrenheit or vice versa press and hold the On Off button for 5 seconds while the water heater is OFF Setting Controller to Mute To eliminate the beeps when keys are pressed or to turn the beeps back on press and hold both the and buttons un...

Page 8: ...h to wipe cabinet Vent System The vent system should be inspected at least annually for blockages or damage Motors Motors are permanently lubricated and do not need periodic lubrication Keep fan and motor free of dust and dirt by cleaning annually Remote Controller Use a soft damp cloth to clean the remote controller Do not use solvents Lime Scale Build up If you receive Error Code LC refer to the...

Page 9: ...eck gas solenoid valves for open or short circuits Remove burner cover and ensure all burners are properly seated Remove burner plate and inspect burner surface for condensation or debris 12 Flame Failure Check that the gas is turned on at the water heater and gas meter Check for obstructions in the flue outlet Ensure gas line meter and or regulator is sized properly Ensure gas type and pressure i...

Page 10: ...e build up Ensure fan blade is tight on motor shaft and is in good condition Replace sensor 52 Modulating Solenoid Valve Signal Abnormal Check modulating gas solenoid valve wiring harness for loose or damaged terminals Measure resistance of valve coil 61 Combustion Fan Failure Ensure fan will turn freely Check wiring harness to motor for damaged and or loose connections Measure resistance of motor...

Page 11: ...ater heater continues to run The fan is designed to continue running for a short time after the flow of water stops This is to ensure constant water temperatures during rapid starting and stopping as well as exhausting any residual gas flue products from the unit Consideration of care for your water heater should include evaluation of water quality If the water quality exceeds the target levels pr...

Page 12: ...ater and cold water lines V3 and V4 3 Connect pump outlet hose H1 to the cold water line at service valve V2 4 Connect drain hose H3 to service valve V1 5 Pour approximately 4 gallons of virgin food grade white vinegar or citric acid into pail 6 Place the drain hose H3 and the hose H2 to the pump inlet into the cleaning solution 7 Open both service valves V1 and V2 on the hot water and cold water ...

Page 13: ...t pressures in excess of 1 2 psi 3 5 kPa 13 84 in W C The appliance must be isolated from the gas supply piping system by closing its individual manual shutoff valve during any pressure testing of the gas supply piping system at test pressures equal to or less than 1 2 psi 3 5 kPa 13 84 in W C Follow the installation instructions and those in Care and Maintenance for adequate combustion and ventil...

Page 14: ... Non Combustibles 305 505 705 305 505 705 Top of Heater 6 inches 152 mm 12 inches 305 mm 2 inches 51 mm 2 inches 51 mm Back of Heater 0 zero 0 zero 0 zero 0 zero Front of Heater 6 inches 152 mm 24 inches 610 mm 6 inches 152 mm 24 inches 610 mm Sides of Heater 2 inches 51 mm 2 inches 51 mm 1 2 inch 13 mm 1 2 inch 13 mm Floor Ground 12 inches 305 mm 12 inches 305 mm 12 inches 305 mm 2 inches 51 mm V...

Page 15: ...soap and water or an equivalent nonflammable solution as applicable Since some leak test solutions including soap and water may cause corrosion or stress cracking the piping shall be rinsed with water after testing unless it has been determined that the leak test solution is non corrosive Always use approved connectors to connect the unit to the gas line Always purge the gas line of any debris bef...

Page 16: ...ropane Gas Pipe Size inches 3 4 1 1 1 4 1 1 2 10 273 514 1060 1580 20 188 353 726 1090 30 151 284 583 873 40 129 243 499 747 50 114 215 442 662 60 104 195 400 600 70 95 179 368 552 80 89 167 343 514 90 83 157 322 482 100 79 148 304 455 125 70 131 269 403 150 63 119 244 366 175 58 109 224 336 200 54 102 209 313 Length Length Pipe Size inches 1 2 3 4 1 1 1 4 10 291 608 1150 2350 20 200 418 787 1620 ...

Page 17: ...ble water heating appliance Ensure that the water filter on the water heater is clean and installed An approved pressure relief valve is required by the American National Standard ANSI Z21 10 3 Canadian Standard CSA 4 3 for all water heating systems The relief valve must comply with the standard for Relief Valves and Automatic Gas Shutoff Devices for Hot Water Supply Systems ANSI Z21 22 and or the...

Page 18: ...ompliance with local building code requirements It is the responsibility of the contractor engineer to ensure installation is in accordance with all local building codes Confer with local building officials before installation Freeze Protection Piping Warranty does not cover damage due to freezing When electrical power and gas are supplied to the water heater it will not freeze in environments as ...

Page 19: ...rain Valve KEY This is not an engineered drawing It is intended only as a guide and not as a replacement for professionally engineered project drawings This drawing is not intended to describe a complete system It is up to the contractor engineer to determine the necessary components and configuration of the particular system being installed This drawing does not imply compliance with local buildi...

Page 20: ... is not an engineered drawing It is intended only as a guide and not as a replacement for professionally engineered project drawings This drawing is not intended to describe a complete system It is up to the contractor engineer to determine the necessary components and configuration of the particular system being installed This drawing does not imply compliance with local building code requirement...

Page 21: ...eturn plumbing Pump to be of bronze or stainless construc tion This is not an engineered drawing It is intended only as a guide and not as a replacement for professionally engineered project drawings This drawing is not intended to describe a complete system It is up to the contractor engineer to determine the necessary components and configuration of the particular system being installed This dra...

Page 22: ... pipe fittings Avoid dips or sags in horizontal vent runs by installing supports per the vent manufacturer s instructions Support horizontal vent runs every four feet and all vertical vent runs every six feet or in accordance with local codes Vent diameter must not be reduced Do not connect the venting system with an existing vent or chimney Do not common vent with the vent pipe of any other water...

Page 23: ...res the water heater will run properly Blocked flue error codes and shutdowns may result if dip switch no 1 is not in the correct position On the 305 and 505 models the maximum water flow capacity will be reduced by about 10 when dip switch no 1 is OFF NOTICE Number of 90 Elbows 0 1 2 3 4 5 6 41 ft 1 12 5 m 35 ft 2 10 7 m 29 ft 3 8 8 m 23 ft 4 7 0 m 17 ft 4 5 2 m 11 ft 4 3 4 m 5 ft 4 1 5 m 1 If th...

Page 24: ...4 NA ProTech Systems FasNSeal FSAAU4 FSRC4 FSBS4 FSDVPTB04LH FSDVWT4 Metal Fab Corr Guard 4CGOA 4CGSWC 4CGSWMCM 4CG7HT90 4CG7HT Venting Products Vent Manufacturer Contact Information for Installation Instructions and Parts Lists Heat Fab Telephone 800 772 0739 Fax 413 863 4803 E mail custsvc heat fab com Web Site www heatfab com Ubbink Telephone 888 928 3719 500 Tennessee Waltz Parkway Ashland Cit...

Page 25: ... Description US Installations A Clearance above grade veranda porch deck or balcony 12 inches 30 cm B Clearance to window or door that may be opened 12 inches 30 cm C Clearance to permanently closed window 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 E Clearance to unventilated soffit F Cleara...

Page 26: ...water heater terminals at different levels 12 12 36 INSIDE CORNER V V 0 91 m to ventilated or unventilated soffit or eve vent or to a deck or porch 0 30 m to an inside corner 0 30 m between water heater terminals at same level 0 61 m to wall or parapet 0 30 m between water heater terminals at same level 12 V V 1 52 m vertically between water heater terminals V 60 V Vent terminal represents concent...

Page 27: ... 5 Install the 4 screws at the vent top and tighten the 4 screws at the bracket Secure the first vent component to the water heater with one self tapping screw at the hole located above the condensate collector Bracket Condensate Collector Securing Screw Horizontal Termination without using the Condensate Collector Maximum Height 5 feet 1 52 m Regions of cold climate will create more condensate in...

Page 28: ... screws attach the pipe to the air intake terminal 5 Apply a bead of silicone around the pipe and air intake terminal ensuring an air tight connection Exhaust Pipe Assembly Refer to the manufacturer s installation instructions for the specific exhaust vent system Venting Clearances to Combustibles Vent Size Enclosed Unenclosed Horizontal Vertical Horizontal Vertical 4 102 mm 4 102 mm 1 26 mm 4 3 1...

Page 29: ...erminations The air intake requires a return bend or two 90º elbows to prevent entry of rain SLOPE INTAKE AND EXHAUST TOWARD OUTSIDE TERMINATION MINIMUM 1 4 PER FOOT Horizontal with Concentric Termination Flue Installation for the 705 Model ...

Page 30: ... cable or 1 Multi Unit connection kit 3 1 Multi Unit connection kit and 1 Multi Unit connection cable 4 1 Multi Unit connection kit and 2 Multi Unit connection cables 5 1 Multi Unit connection kit and 3 Multi Unit connection cables Guidelines Do not install both the 2 Unit connection cable and the Multi Unit connection kit because they are not designed to operate together Water heaters should be i...

Page 31: ...uld be a non polarized two core cable with a minimum gauge of 22 AWG The maximum cable length from each controller to the water heater depends on the total number of wired controllers connected to the water heater Number of Wired Controllers Maximum Cable Length for each Controller to Water Heater 1 328 ft 100 m 2 164 ft 50 m 3 or 4 65 ft 20 m Location Controllers Wire controllers in parallel Wate...

Page 32: ...ss hole at the base of the unit and connect the wires to the controller terminals on the right hand side bottom of the PCB 11 Secure the controller cable using the clamp provided 12 Replace plastic cover over PCB and then replace the cover of the water heater Do not attempt to connect the remote controllers with the power on There is 120 volt potential next to the remote controller connections ins...

Page 33: ...TO APPLIANCE 1 Turn off all electric power to the appliance using the ON OFF button 2 Set the thermostat to lowest setting 3 Locate the manual gas valve on the side of the heater Turn the manual valve clockwise to the full OFF position OPERATING INSTRUCTIONS 1 STOP Read the safety information above 2 Set the thermostat to lowest setting 3 Turn off all electric power to the appliance using the ON O...

Page 34: ...ow Data Water Flow gpm delta T Temperature Rise ºF 0 5 10 15 20 25 30 35 40 45 0 2 4 6 8 10 12 0 10 20 30 40 50 60 70 80 90 100 505 305 Pressure Loss ft head Pressure Loss psi Water Flow gpm 705 0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 0 10 0 0 25 50 75 100 125 150 705 505 305 ...

Page 35: ...ng system and any additional plumbing pressure losses The pressure drop curve based on the water heater model is provided in this manual Replacement When replacing an existing space heating application s water heating source boiler tank water heater tankless water heater etc with these water heaters ensure that the water heaters are sized to adequately provide the necessary BTU input for the desir...

Page 36: ...C Height Unit 22 9 582 23 6 600 D Height with brackets 25 5 648 2 25 2 639 8 E Hot Water Outlet from wall 3 6 91 4 3 110 F Hot Water Outlet from center 4 3 110 2 4 61 G Cold Water Inlet from wall 2 8 70 3 7 94 H Cold Water Inlet from center 1 1 27 2 0 52 I Gas Connection from wall 4 3 109 2 2 56 2 J Gas Connection from center 3 5 89 4 3 110 From base to gas connection 1 6 40 1 6 40 From base to co...

Page 37: ...V DC5V A B C SG SWITCHING POWERSUPPLY THERMISTOR CIRCUIT B SG RELAY 1 A WATERFLOW SENSOR CIRCUIT WATERFLOW CONTROLDEVICE CIRCUIT A SG A SG SG A QS SG FR FLAME DETECTING CIRCUIT FLAMEROD GND SG A REMOTE CONTROLLER CIRCUIT A B E PG A B C SG SG B VARISTOR ARRESTER GND SG WATERFLOW SENSOR WATERFLOW CONTROLDEVICE BY PASSFLOW CONTROLDEVICE M M DC12V DC170V D E PG SV3 SV2 SV1 SV0 RELAY DRIVING CIRCUIT D ...

Page 38: ...red as on demand What will be done Repair or replacement of the covered product or any part or component that is defective in materials or workmanship as set forth as follows Payment of reasonable labor charges associated with the repair or replacement of any such part or component All repair parts must be genuine OEM parts All repairs or replacements must be performed by an individual or servicin...

Page 39: ...uthorized to make any other warranties on behalf of the manufacturer Except as expressly provided herein there are no other warranties expressed or implied including but not limited to warranties of merchantability or fitness for a particular purpose which extend beyond the description of the warranty herein and further the manufacturer shall not be liable for indirect incidental special consequen...

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