Bosch Therm External Water Filter

The Bosch External Water Filter (8703305356) replaces the internal water filter that comes with the heater. Having the water filter external means it is located under the Bosch Therm tankless water heater and is therefore easy to access and clean out. Odds are that if you do not install the external water filter then the internal water filter will not get regularly cleaned out as you would have to open the cover and remove the control board to get to the internal water filter, which is not very convenient.  It is recommended to clean the filter screen at least once a year for periodic maintenance.

The Bosch Therm External Water Filter is designed to work with the following Bosch Therm Tankless Water Heaters: C 1210 ESC, GWH C 920 ESC, C 1210 ES, GWH C 920 ES, C 1050 ES, GWH C 800 ES, C 950 ES, 940ES, 940ESO, GWH 715 ES, and 830ES.

This accessory is not included with these heaters and is highly recommended.

The Bosch External Water Filter is included with the Bosch Integra 500 and Bosch Evolution 500 water heaters.

The Bosch External Water Filter is NOT compatible with the new Bosch Greentherm C950ES and Greentherm C1050ES tankless water heaters.

Replacement filter screens part 8700507059 are available for the Bosch External water filter.  Please call us at 866-289-4652

Descaling Powerstream Pro RP17PT & RP27PT

The Bosch Pro electric tankless water heaters, Powerstream Pro models RP17PT and RP27PT are high kilowatt electric tankless heaters that heat water on demand as the water passes through them. The modules inside consist of coiled elements that heat the water. The heating elements produce extreme heat inside the modules to heat the water on demand.

The heat that is produced by the heating elements in the modules sometimes counteracts with the mineral deposits in the water. If there is a high mineral content due to a hard water area then these mineral deposits known as "scale deposits" will over time attach themselves to the heating coils inside the modules.

All Bosch Powerstream Pro electric tankless water heaters should never be descaled with any type of solution such as vinegar, muriatic acid, etc. The use of descalants flushed through the heater does not have much effect on the mineral deposits attached to the elements. Another point of trying to flush descalant through an electric tankless heater is that it will loosen some of the mineral deposits in the heater and will have a damaging effect on the flow transducer and other parts inside the tankless heater that detects the flow of water and will interrupt the signal to the circuit board itself.

The best protection against mineral deposits (scale) forming on the coils in the electric tankless heater is to check the quality of the water in your area before installing and if the water has a high mineral content then it is recommended to install a water softener or scale stopper system. The water softener or scale stopper will filter out almost all of the minerals and treat the water so the electric tankless water heater will have a longer life with less minerals building up inside.