User manual BOSCH GWH 425 EF

[. . . ] 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, adjustment, alteration, service or maintenance can cause injury or property damage. For assistance or additional information consult a qualified installer, service agency or the gas supplier. [. . . ] For installation on a private well system with the use of a pressure tank, the lowest pressure range setting recommended is 30-50 psi (2. 07-3. 45 bar). 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. No reducing coupling or other restriction may be installed in the discharge line. The discharge line must be installed such that it allows complete drainage of both the PRV and the line. The location of the PRV must be readily accessible for servicing or replacement and be mounted as close to the water heater as possible. To install the PRV, a suitable fitting connected to an extension on a "T" fitting can be sweated to the hot water line. See Fig 8. PIPE PRV TO APPROPRIATE DISCHARGE Fig. 8 - Plumbing and Pressure Relief Valve Fig. 7 - Water valve and water connectors, top view 6 720 607 017 13 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. Do not rely on the gas or water piping to ground the metal parts of the heater. CAUTION: Label all wires prior to disconnection when servicing controls. Wiring error can cause improper and dangerous operation. Verify proper operation after servicing. The 425 EF requires an electrical power supply from 120VAC 60Hz circuit and must be properly grounded. - A means for switching off the 120 VAC power supply must be provided. - The heater is wired as shown in the wiring diagram. (Fig 9). 123456- microswitch On / Off switch temperature limiter flue gas safety device burner electrovalve pilot electrovalve 7 - Diaphragm switch 8 - ionization probe (flame sensor) 9 - fuse 10 - pilot electrode 11 - electric control box 12 -power cord 13 - exhaust fan Fig 9: Wiring Diagram for 425 EF 14 6 720 607 017 OPERATING INSTRUCTIONS Before operating the heater, make sure that the system is filled with water. Open the cold water inlet supply to the heater fully. Open a hot water faucet to permit the water to fill the heater and the piping and to eliminate the air trapped in the system Close the hot water faucet after the water flows freely and all the air has escaped from the system. The water heater is now ready to operate. 6. Turn the hot water faucet on to the minimum flow required to activate the heater. [. . . ] to defects or malfunctions resulting from failure to properly install, operate or maintain the unit in accordance with the printed instructions provided; 2. to damage or abuse, accident, neglect or freezing and other acts of nature; 3. to damage resulting from operation with either the flame sensor rod or overheat sensor removed; 4. to failure of the heat exchanger resulting from the operation of the water heater in a corrosive atmosphere or at water temperatures exceeding the maximum rating, or if the water heater is not supplied with potable water; 5. [. . . ]