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MODEL 250SX NG and 250SX LP - INDOOR MODEL
Temperature Modulated with Electronic Ignition
Not approved for space heating purposes
250 SX NG - Natural Gas
250 SX LP - Liquefied Petroleum (LP) Gas
Warning: If the information in this manual is not
followed exactly, a fire or explosion may result
causing property damage, personal injury or death.
Do not store or use gasoline or other flammable
vapor and liquids in the vicinity of this or any other
appliance.
Improper
installation,
service or maintenance can cause injury or
property damage. Refer to this manual. For
assistance or additional information consult a
qualified installer, service agency or the gas
supplier.
In the Commonwealth of Massachusetts this
product must be installed by a licensed plumber or
gas fitter.
Upon completion of the installation, these
instructions should be handed to the user of the
appliance for future reference.
Suitable for heating potable water only
(Intended for variable flow applications)
adjustment,
alteration,
What to do if you smell gas
• Close gas valve. Open windows.
• Do not try to light any appliance.
• Do not touch any electrical switch; do not use any
phone in your building.
• If you cannot reach your gas supplier, call the fire
department.
• Immediately call your gas supplier from a neighbor's
phone. Follow the gas supplier's instructions
• Installation and service must be performed by a
qualified installer, service agency or the gas supplier.
Related Manuals for Bosch 250 SX LP
Summary of Contents for Bosch 250 SX LP
- Page 1 Not approved for space heating purposes (Intended for variable flow applications) 250 SX NG - Natural Gas 250 SX LP - Liquefied Petroleum (LP) Gas Warning: If the information in this manual is not What to do if you smell gas followed exactly, a fire or explosion may result •...
- Page 2 Index Index Warning Warning Warning: If the information in this Appliance details manual is not followed exactly, a fire or Features explosion may result causing property 250 SX Specifications (Technical data) damage, personal injury or death. Dimensions and Minimum installation clearances General rules to follow for safe operation Proper location for installing your heater Improper...
- Page 3 Warning Warning: Field wiring connections and electrical grounding must comply with local codes, or in the absence of local codes, with the latest edition of the National Electric Code, ANSI/NFPA 70, or in Canada, all electrical wiring must comply with the local codes and the Canadian Electrical Code, CSA C22.1 Part 1.
- Page 4 Sulfid) • Minimum water flow: 0.8 gallon/minute (3 l/m) • Vent termination kit. • Minimum recommended water pressure: 30 PSI BOSCH is constantly improving its (2.07 bar) products, therefore specifications are • Connections: subject to change without prior notice.
- Page 5 Appliance details Combustion Do not lose this manual. Please complete and return the enclosed product registration card. • NOx ≤ 55 ppm Before installing the unit, be certain you have the • CO ≤ 250 ppm correct heater for your type of Gas - Propane or •...
- Page 6 Appliance details Dimensions and Minimum installation clearances Fig. 4 Dimensions Cover On/Off switch Reset button LCD display Program button Temperature buttons Fig. 5 Minimum clearances Model 250 SX 12” TOP (A) FRONT (B) 4” 0” BACK SIDES 4” FLOOR (C) 12”...
- Page 7 Appliance details General rules to follow for safe Proper location for installing your operation heater B 1. You should follow these instructions when you Carefully select the location of the water heater. For install your heater. In the United States: The your safety and for proper heater operation, you must installation must conform with local codes or, in the provide combustion air to the heater and a proper...
- Page 8 Appliance details Clearances The 250 SX is design certified for installation on a combustible wall (see 2.7 Mounting installation) provided the floor covering below the heater is noncombustible. For installations in an alcove or closet, maintain the minimum clearances to combustible and non-combustible materials listed below.
- Page 9 Appliance details Venting construction, infiltration air is normally adequate to provide air for combustion. Warning: Do not reduce the vent • Appliances located in confined spaces: (exhaust and combustion) pipe sizes The confined space must be provided with two and do not common vent with any other permanent openings, one commencing within 12 vented appliance or stove.
- Page 10 Appliance details The maximum flue gas exhaust temperature on the 250 SX is 437°F (225°C) Venting Exhaust * Exhaust * Exhaust Combustion Combustion Vent pipe Vent pipe Options vent vent vent air pipe air pipe clearances clearances diameter maximum minimum diameter maximum within an...
- Page 11 Appliance details Note: reduce 2½ ft for each 90° elbow used after the Use of the external condensate drain tube kit first one, reduce 1 ¼ ft for each 45° elbow. (supplied with the heater) on the exhaust collar B The condensate drain tube kit must be used for all Vent Safety System installation types.
- Page 12 Appliance details 2.9.1 Venting options Open combustion installation (SINGLE PIPE SYSTEM) Installing this water heater as a room sealed (TWIN PIPE SYSTEM) is the recommended method. Contact Not recommended in cold climate areas, see CEC or dealer for available vent termination kits and Chapter 2.8.
- Page 13 Appliance details Recommended exhaust vent terminator position Fig. 16 Ref. Description Minimum distance Directly below an opening; operable windows, doors and any non- 36 in mechanical fresh air openings Below a gutter, sanitary pipework or eaves 24 in Below a gutter, sanitary pipework or eaves, protected by metal 12 in shielding From any internal corner...
- Page 14 Appliance details Supporting the exhaust vent system The venting materials and accessories required to properly install the water heater are available from CEC and their distributors. Fig. 17 Horizontal side wall venting installation (combustion air piping not being shown) Fig. 19 Vertical venting installation (combustion air piping not being shown) A condensate drain tube must be attached to the exhaust collar of the heater for all vent type applications,...
- Page 15 Appliance details 2.10 Gas piping & connections Before connecting the gas supply, check the rating plate on the right side of the heater to be sure that the heater is rated for the same gas to which it will be connected.
- Page 16 Appliance details FOR NATURAL GAS Maximum Capacity of pipe in Cubic Feet of Gas per Hour for Gas Pressure of 0.5 Psig or less and a Pressure drop of 0.3 in Water Column (0.75mbar).(Based on a 0.60 Specific Gravity Gas) Btu numbers given in thousands. Follow boxed numbers for piping just one 250 SX (example: ¾”...
- Page 17 Appliance details 2.11 Gas line sizing 2.12 Measuring gas pressure B It is strongly recommended that the Natural Gas pipe 2.12.1 Connecting Manometer be Black Iron pipe the entire distance from the B Shut off gas. outside meter to the inlet of the gas connection. ¾” B Remove front cover and locate inlet gas pressure Black Iron pipe up to 20 feet (6.1m) and 1”...
- Page 18 Appliance details piping be used for the water heater connections (follow Static Gas Pressure Reading (see Chapter 2.12) local codes if more stringent). Never sweat any rigid piping directly to or beneath the water connections, enter here: ___________________ damage can occur to the internal water valve from heating of the pipe.
- Page 19 Appliance details 2.14 Electrical connections 2.16 For your safety read before operating your water heater Warning: safety reasons, disconnect the power supply to the Warning: If you do not follow these heater before any service or testing is instructions exactly, a fire or explosion performed.
- Page 20 Appliance details NOTE: on a first time initial instal- lation or after gas line work has been done, existence of air in the gas line will cause ignition delay when the hot water is turned on. This will result in an error (EA) on the units display screen.
- Page 21 Operation instructions Operation instructions Fig. 27 B Press buttons in order to reach On/Off switch Reset button requested temperature. Program Key Increasing temperature selector Decreasing temperature selector LCD display Power B To start the appliance switch the button to position (I).
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Page 22: Table Of Contents
Operation instructions Setting the water temperature The desired temperature of the hot water can be adjusted on the front control panel of the heater. The 250 SX has an electronically controlled gas valve that modulates the burner input in response to both varying hot water flow rates and/or changes in any incoming and outgoing water temperatures. - Page 23 Operation instructions Use of remote control accessory Fig. 34 Reset button If the problem persists, contact your installer. Program button Fig. 31 Remote control Program button can be used/programmed in the The wireless remote control accessory and the appliance and in the remote control. temperature selector buttons on the front of the water heater operate identically.
- Page 24 Maintenance and service Maintenance and service heater will communicate the source by these error codes. Warning: Always turn off the electrical BURNERS DO NOT IGNITE WHEN HOT WATER IS power supply, turn off the manual gas TURNED ON valve and turn off the manual water •...
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Page 25: Inlet (ºf)
Troubleshooting Test by following 4th bullet under BURNERS DO control of the heater can be lowered to produce a NOT IGNITE WHEN HOT WATER IS TURNED ON. more comfortable hot water temperature. • Inlet water pressure erratic LOW WATER FLOW/PRESSURE fluctuating supply water pressure •... -
Page 26: Inlet (ºf)
Troubleshooting Display Cause Solution Temperature limiter opened circuit (overheat). Check connections.* Trips at 220F (104C). Check heat exchanger condition.* No ionization during safety time (safety time out). Check gas pressure.* Note: appliance makes 3 ignition attempts Check that gas is not diluted with air, as a result before entering error mode “EA”. - Page 27 Electrical diagram Electrical diagram Fig. 37 Electrical scheme Intlet water temperature sensor Ionization sensor Water flow sensor Over heat protection Temperature limiter Gas valve Water valve AC Plug Ignition electrode Display PCB ON/OFF switch Fuse T 2,5A Fuse T 3,15A Terminal block Ground post Outlet water temperature sensor...
- Page 28 250 SX Functional scheme 250 SX Functional scheme Fig. 38 Functional scheme 6 720 607 057...
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Page 29: Inlet (ºc)
Interior components diagram and parts list Interior components diagram and parts list Interior components Fig. 39 Components Cover On/Off switch Reset button LCD display Program button Temperature switches Flue gas collector Mixer Heat exchanger Observation window Inlet air duct Control unit Exhaust fan Water valve Gas valve... - Page 30 Interior components diagram and parts list Components diagram Fig. 41 Components Diagram 6 720 607 057...
- Page 31 Interior components diagram and parts list Parts list Item Description Reference Front cover 8 705 421 837 Shield 8 705 506 661 Heat exchanger 8 705 406 285 Heat exchanger top gasket 8 704 701 052 Clip 8 716 102 607 Heat exchanger bottom gasket 8 704 701 054 O-ring...
- Page 32 Special adjustment for measuring and adjusting CO2 levels Special adjustment for measuring and adjusting CO levels The CO can only be adjusted by a certified gas B. Measuring CO (Cover Installed): technician with a calibrated CO analyzer. B Open hot water taps to achieve a flow rate of at least 4 gallons per minute.
- Page 33 Special adjustment for measuring and adjusting CO2 levels D. Returning to Service: 1. Return slotted cover to original position. 2. Reinstall Torx cover. 3. Remove CO analyzer probe and reinstall flathead screw in exhaust collar. 4. Turn ON/OFF switch to the OFF (O) position and then back to the ON (I) position.
- Page 34 Protecting the environment Protecting the environment Packing The packing box may be fully recycled as confirmed by the recycling symbol Components Many parts in the heater can be fully recycled in the end of the product life. Contact your city authorities for information about the disposal of recyclable products.
- Page 35 Service Labor Costs Aquastar water heaters are warranted by the This warranty does not cover any labor costs Manufacturer (BOSCH) through Controlled Energy associated with service, removal or re-installation of Corp. Controlled Energy Corp. (CEC) will furnish a part(s). All such costs must be borne by the Purchaser.
- Page 36 Installer Checklist, to be performed by installer upon installation Serial Number ___ ___ ___ ___ ___ ___ ___ ___ (8 digit serial number is located on rating plate on right side panel) Gas Pressure Reading* Static__________ Operating__________ Building Water Pressure __________ Range if on Well system __________ Installing Company _____________________________________________...