Bosch Appliances GWH 2700 ES NG, GWH 2700 ES LP, ESVVT manual Domestic hot water recirculation, Gwh

Installation instructions

Connecting the pressure relief valve (PRV)

A 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 min- imum of 4” above a drain and installed such that it allows complete drainage of both the PRV and the line. The discharge line must be placed where it will not cause any damage.

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. 31. 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.

3.11 Domestic hot water recirculation

Although recirculation directly through the tankless water heater is allowed, temperature stability is improved by recirculating through a mini-tank as shown in Fig. 32. By using the design in Fig. 32, there is no recirculation of hot water through the tankless water heater and therefore, does not affect the heat exchanger warranty. Direct recirculation through the tankless water heater is permissible, however, the heat exchanger warranty is reduced; contact Bosch Thermotechnology for further installation requirements. The following drawing is provided to outline one possible recirculation design using the water heater in conjunction with an Ariston mini tank water heater. This schematic is for illustration only and must not be used for actual installation without appropriate engineering and technical advice from a properly licensed professional in the locality where the installation is made.

5		GWH
		2700
		ES
	2	4
1
		3

Fig. 31 Plumbing Connections (with shutoff valves) and Pressure Relief Valve

1Water filter

6720608158-77.1AL

Ariston Minitank

Fig. 32 Recirculation application

1Full port isolation valve

2 Circulator (pump)

3 Check valve

4PRV

5Expansion tank

The use of a small electric mini-tank water heater (4-6 gallon size) should be used for this application and designed so the pump will circulate the water through the mini-tank and the building's hot water return loop only. Timed or thermostatically controlled operation of the pump is commonly done. Contact Bosch Thermotechnology if further information is needed.

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