Bosch Appliances GWH-345/450-ESR-L, GWH-345/450-ESR-N Water connections, Electrical connections

Installation instructions

BIf the CO2 content is too high, use the next smallest restrictor.

BAfter replacing the restrictor, measure CO2 level again. Repeat procedure until correct level is obtained.

BOnce correct reading is obtained, replace screw with gasket in exhaust collar.

BPress On/Off button to turn heater Off and exit Service Mode.

3.10 Water connections

BWhen facing the heater, the ¾” NPT inlet is on the bottom right and the ¾” NPT outlet is on the bottom left (Fig. 29). Install the heater centrally in the build- ing if possible and make piping runs as short as pos- sible.

OUTLET INLET

Fig. 29

BThe use of unions when connecting both water pipes to the inlet and outlet connections is recommended. This will facilitate any necessary servicing.

BAlthough water piping throughout the building may be other than copper, we recommend that copper or suitably rated stainless steel flex line piping be used for the water connections for 3’ on either side of the recirculating water heater (follow local codes if more stringent).

BNever sweat any rigid piping directly to or beneath the water connections, damage can occur to the internal heater components during the sweating process.

BPlastics or other PEX type plumbing line materials are not suitable for connecting directly to the water heater.

BKeep water inlet and outlet pipes to no less than ¾" (19.05mm) diameter to allow the full flow capacity.

B If the cold and hot connections to the heater are reversed, the heater will not function correctly. Be certain there are no loose particles or dirt in the

piping. Blow out or flush the lines before connecting to the water heater.

BFull port shut off valves should be installed on both the cold water supply and hot water outlet lines to facilitate servicing the heater (see Fig. 30).

Connecting the pressure relief valve (PRV)

The listed pressure relief valve supplied with the heater must be installed at the time of installation. 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 a minimum of 4” above a drain and 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. See Fig. 30. To install the PRV, a suitable fitting connected to an extension on a “T” fitting can be sweated to the hot water line.

Support all piping.

Fig. 30 Plumbing Connections and Pressure Relief Valve

3.11 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 must 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.

The GWH-345/450-ESR requires an electrical power supply from a 120VAC 60Hz circuit and must be properly grounded.

A means for switching off the 120VAC power supply must be provided.

The heater is wired as shown in the wiring diagram (chapter 4.8, Fig. 35).

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