Bosch Appliances GWH 260 PN/HN2, GWH 425 PN/HN4GWH 4254 manual Descaling procedure

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Applications manual

 

 

6 Maintenance Drawings

Bosch appliances are designed to last for many years. In order to keep the heater operating properly, periodic maintenance is required. Please consult the installation manual for maintenance intervals. A descaling procedure drawing is included to assist in clearing the water heater of mineral deposits that may build up over time.

6.1 Descaling procedure

This procedure should only be done if there is evidence of scale build-up such as a reduced hot water flow rate or if the water is known to have high levels of minerals such as calcium.

1.Disconnect electrical supply from the water heater.

2.Shut off the water supply to the water heater using (installer supplied) isolation valve.

3.Open hot water taps to drain and relieve pressure from the plumbing system.

4.Drain water from the unit’s heat exchanger by disconnecting inlet and outlet water connections.

5.Connect the line (A) from the outlet of the circulating pump (installer supplied) to the inlet water fitting on the water heater.

6. Using another line (B), connect to the water outlet fitting on the water heater. Route the other end of this line into a descaling reser- voir.

7.Using a 3rd line (C) from the descaling reservoir, connect to the inlet side of circulating pump. Verify there is a filter on the end of the line in the descaling reservoir.

8.Make sure all connections are “hand tight.”

9.Fill tank with descaling solution so lines inside are submersed. We recommend a straight white vinegar. If using a commercial descalant, refer to manufacturer’s instructions for proper dilution ratio.

11.Operate the circulating pump.

12.Make sure there are no leaks and the solution is flowing from the descaling reservoir through the heat exchanger and returning to the reservoir.

13.Run solution through the heat exchanger until the solution returning to the descaling reservoir comes out clear. (Changing to a fresh solution may be necessary during this process)

14.Disconnect all lines and drain all solution from heat exchanger. Properly discard of solution.

15.Position a container below the hot water outlet and connect cold water supply. Open cold water supply isolation valve and flush heat exchanger with clean water.

16.Shut cold water isolation valve and reconnect hot water supply to the water heater.

17.Reconnect electrical supply to unit, open water isolation valves, and return the unit to service.

Application manual 11.2007

Bosch Water Heating

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Contents Applications manual Table of Contents Introduction Sizing by Chart Sizing tankless water heatersDefinitions Rule of thumb sizingGas Appliance Sizing Chart Features GWH 715 ES Installation SpecificationsApplications manual GWH 715 ES Installation Clearances Installation guidelinesGWH C 800 ES Technical Specifications GWH C 800 ES Installation SpecificationsGWH C 800 ES Installation Clearances Description Min Distances Outdoor Installation for GWH 715 ESGWH C 800 ES GWH 345 ESR Technical Specifications GWH 345 ESR Installation SpecificationsGWH 450 ESR Installation Clearances GWH 450 ESR Installation Specifications GWH 450 ESR Technical SpecificationsGWH 425 EF Technical Specifications GWH 425 EF Installation SpecificationsGWH 425 EF Installation Clearances GWH 425 HN Installation Specifications GWH 425 HN Installation ClearancesGWH 425 HN Technical Specifications Establish a one-foot rise before any elbowsGWH 425 PN Technical Specifications GWH 425 PN Installation SpecificationsGWH 425 PN Installation Clearances GWH 260 PN Technical Specifications GWH 260 PN Installation ClearancesGWH 260 PN Installation Specifications Electrical requirements Maximum flow rate at given temperature riseTechnical Specifications Powerstream Pro RP1P, RP2P, RP3P, RP7P, RP9P,RP12PT Ariston Pro GL2.5Ti, GL4Ti, GL8Ti Introduction Point-of-use applicationsPotable water Temperature and pressure Service valveRelief valve SinkService valve Sink Flow direction Temperature and pressure relief valve Sink Service valves Low flow Flow direction ShowerService Sink valves Powerstream Pro RP17PT or RP27PTPowerstream Pro whole house applications Standard tub fixtureHotCold Symbols Bosch ProTankless gas water heaterHot Cold Parallel unit applications Pressure relief valves Bosch GWH 715 ES Bosch GWH C 800 ESCascading unit applications GWH 715 ES and GWH C 800 ES cascadingPressure Bosch GWH 345 ESR Bosch GWH 450 ESR Single unit tank loading application plumbing diagramCold water Feed DHW Single Unit Tank Loading Electrical Diagram ESR control BoardRadiant space heating and DHW plumbing diagram Cold waterFeed External storage tankRadiant Space Heating and DHW Electrical Diagram Radiant space heating and DHW electrical diagramBosch GWH 345 ESR, Bosch GWH 450 ESR Fan coil space heating and DHW plumbing diagramFan Coil Cold water Fan Coil Space Heating and DHW Electrical Diagram Fan Coil space heating and DHW electrical diagramDrawing # BB OL RevA 10/07 Baseboard Space Heating and DHW Electrical Diagram Drawing # Bbaol RevA 10/07 Pkps Insulate piping Cold water feed Terminal box Baseboard Radiant Panel Back Flow preventerDrawing # EID Bbol CN revA 10/07 Descaling procedure Circulating pump Flow direction Filter Service valves Applications manual Applications manual Applications manual Applications manual BBT North America Corporation