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Water heaters for use with Natural and L.P.G.
GWH 425 EF
Flow Modulated with Electronic Ignition and Power Venting
Suitable for heating potable water only - Not approved for space heating purposes
(Intended for variable flow applications with steady cold water inlet temperatures)
GWH-425-EF-N
GWH-425-EF-L
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.
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.
PRO TANKLESS
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Table of Contents
Related Manuals for Bosch GWH-425-EF-N
Summary of Contents for Bosch GWH-425-EF-N
- Page 1 Suitable for heating potable water only - Not approved for space heating purposes (Intended for variable flow applications with steady cold water inlet temperatures) PRO TANKLESS GWH-425-EF-N GWH-425-EF-L Warning: If the information in this manual is not What to do if you smell gas followed exactly.
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Page 2: Table Of Contents
TABLE OF CONTENTS WARNING Improper installation, Specifications ............... Page 3 adjustment, alteration, service or maintenance can cause Rules for safe operation ..........Page 5 injury or property damage. Refer to this manual. For Locating the Heater ............ Page 5 assistance or additional information consult a qualified Combustion Air Requirements ........ -
Page 3: Specifications
Principle of Operation: 425 EF LP and 425 EF NG Specifications When a hot water faucet is opened, the flow of water through 425EF NG 425 EF LP the heater causes the gas valve to open. At the same time a microswitch is activated which sends a spark to the pilot. - Page 4 FRONT VIEW SIDE VIEW MINIMUM INSTALLATION CLEARANCES FROM COMBUSTIBLE AND NON COMBUSTIBLE MATERIALS FOR ALCOVE OR CLOSET INSTALLATIONS MODEL 425 EF TOP (A) 12 " FRONT (B) 4 " BACK 0 " * SIDES 4 " FLOOR (C) 12 " VENT DIAMETER 4 "...
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Page 5: Rules For Safe Operation
The heater may still operate even when improperly vented. GENERAL RULES TO FOLLOW It will, however, be less efficient and could eventually damage FOR SAFE OPERATION the heater. It could even result in human sickness or death due to oxygen deprivation and carbon monoxide poisoning. 1. -
Page 6: Combustion Air Requirements
Appliances located in confined spaces: The confined space COMBUSTION AIR REQUIREMENTS must be provided with two permanent openings, one The 425 EF water heater holds cold water in its copper commencing within 12 inches of the top and one heat exchanger and brass water valve when not in use. commencing within 12 inches of the bottom of the enclosure. -
Page 7: Mounting The Heater
The incandescent particle tray (shipped loose in the carton MOUNTING INSTALLATION with the water heater) must be attached at the bottom of the water heater front cover at the time of installation. Use The 425 EF is design certified for mounting on a wall. the screws provided. -
Page 8: Venting The Heater
feet (4.6 m) with two 90-degree elbows. Subtract 5 feet from the total vent length for each additional 90-degree VENTING elbow used. No more than four 90-degree elbows may be used. Any short vertical portion of vent pipe used in the vent system shall be considered part of the allowable 15 WARNING: Do not reduce the vent pipe size and feet (4.6 m) maximum run. - Page 9 4”single wall venting only. Use stainless steel (AL29-4C) or galvanized pipe of 26 minimum gauge must be used. Each connection must be properly sealed. Approved Vent Terminal (FXHOOD or other approved terminal) The FXHOOD is design approved with the 425 EF and has a built in back draft flapper to prevent negative air from freezing the 425 EF –...
- Page 10 The approved vent terminal must be installed so that flue gases will not jeopardize people, overheat combustible structures or enter into buildings, and so that proper clearances are maintained (See Fig 5). a) The vent terminal shall not be less than 7 feet above a public walkway. b) The vent terminal shall terminate at least 3 feet above any (mechanical) air inlet within 10 feet.
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Page 11: Gas Connections
GAS LINE SIZING -It is strongly recommended that the Natural Gas pipe GAS CONNECTIONS be Black Iron pipe the entire distance from the outside meter to the inlet of the 425 EF regulator. 1/2” Black Iron pipe up to 10 feet, 3/4” Black Iron pipe up to 40 feet and 1”... - Page 12 GAS PIPING, CONNECTIONS Before connecting the gas supply, check the rating plate on the right side of the front cover to be sure that the heater is rated for the same gas to which it will be connected. In the United States: The installation must conform with local codes or, in the absence of local codes, the National Fuel Gas Code ANSI Z223.
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Page 13: Water Connections
Connecting the pressure relief valve (PRV) WATER CONNECTIONS The listed pressure relief valve supplied with the heater must be installed at the time of installation. Should a discharge line be added to the PRV no valve is to be placed between the PRV and the heater. -
Page 14: Electrical Connections
ELECTRICAL CONNECTIONS WARNING: For safety reasons, disconnect the power supply to the heater before any service or testing is performed. WARNING: This heater must be electrically grounded in accordance with the most recent edition of the National Electrical Code, NFPA 70. In Canada, all electrical wiring to the heater should be in accordance with local codes and the Canadian Electrical Code, CSA C22.1 Part 1. -
Page 15: Safety Before Turning On The Heater
OPERATING INSTRUCTIONS 6. Turn the hot water faucet on to the minimum flow required to activate the heater. The automatic ignition system first Before operating the heater, make sure that the system is ignites the safety pilot burner which then ignites the main filled with water. -
Page 16: Maintenance & Service
140° and 95°F at various flow rates between 2.0 and 4.0 Water Valve (Part # 8707002802): The water valve on gallons per minute. The position you select on the this heater should be serviced periodically. Lubricate temperature selector dial will depend on the temperature of component #36 on page 21 with a small amount of silicon, the incoming water (50°F is average in the U.S.). -
Page 17: Trouble Shooting
3. Water flow is not sufficient to activate heater. Water flow rate at faucet is below minimum flow needed to activate heater. When temperature adjustment knob is turned all the way clockwise, the model 425 EF requires 1/2 gallon per minute flow to activate the heater. As a reference, this is a flow which would fill a quart jar in 30 seconds. - Page 18 PILOT SPARKS CONTINUOUSLY WITH NO WATER Mineral deposits can eventually (3-5 years in hard water RUNNING areas) corrode the water valve parts to a point where they will need replacing. Any sign of moisture at the bleed hole 1. Microswitch needs adjustment is a sign that the water valve needs to be replaced If no water is running, but pilot electrode continuously sparks, immediately.
- Page 19 WATER IS TOO HOT HOT WATER TEMPERATURE FLUCTUATES / UNIT DEACTIVATED 1. Temperature Selection too high 1. Unbalanced pressure in waterlines Turn the temperature adjustment knob counter-clockwise The added restriction caused by the 425 EF in the hot water (to the left) to lower the maximum water temperature. system can result in uneven pressures between the cold Note: This will increase the activation flow rate.
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Page 20: Diagram Of 425Ef
Diagram of 425 EF Fig. 15 - 6 720 606 601-12.1AL electric control box Heat exchanger Power cord Pilot assembly on/off switch Burner manifold gas Temperature adjustment selector pressure test nipple Microswitch Main gas burner Gas inlet gas pressure test nipple Pilot gas tubing Exhaust Fan Gas valve... -
Page 21: Components And Parts List
- INTERIOR COMPONENTS DIAGRAM AND PARTS LIST Fig. 16 6 720 607 017... - Page 22 Fig. 16 INTERIOR COMPONENTS DIAGRAM AND PARTS LIST 425 EF Cover 8 705 421 775 Temperature adjustment knob 8 702 000 111 Temperature adjustment collar 8 700 403 008 Draft diverter 8 705 505 451 Heat exchanger 8 705 406 235 Overheat sensor (ECO) 8 707 206 040 Main burner...
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Page 23: Flowchart
- Flow chart of 425 EF Fig. 17 6 720 607 017... -
Page 24: Warranty
B OSCH PR O water heaters are warranted by the This warranty does not cover any labor costs associated Manufacturer (BOSCH) through Controlled Energy Corp. with service, removal or re-installation of part(s). All such Controlled Energy Corp. (CEC) will furnish a replacement costs must be borne by the Purchaser. - Page 25 6 720 607 017...
- Page 26 6 720 607 017...
- Page 27 6 720 607 017...
- Page 28 † † † † † † Replacement Parts available from North American Distributor CONTROLLED ENERGY CORP. 340 Mad River Park VULCANO Termodomésticos S.A. Waitsfield, Vermont 05673 Estrada de Cacia Phone 866-330-2730 3801 - 856 Aveiro - PORTUGAL Fax (802) 496-6924 www.protankless.com techsupport@protankless.com ©...