Bosch External Water Filter

The Bosch external water filter part number 8703305356 replaces the existing smaller internal water filter screen inside certain Bosch tankless water heaters.  The external water filter allows for easy access to clean the inlet screen periodically.  Without the external water filter it is very difficult to get at the inlet screen inside the heater.  The Bosch external water filter is designed to be used for Bosch models 250SX/2400E/2400ES/2700ES.  The Bosch Integra 500/Evolution 500/2400ES/2700ES came with the external water filter.

The Bosch external water filter was also good for the older model Bosch heaters such as the older 635ES/635ESO/830ES/940ES/940ESO/C800ES/Therm C950ES/Therm C1050ES and C1210ES/C1210ESC

All of the newer model Bosch tankless water heaters 830ES/940ES/Greentherm C950ES/Greentherm C1050ES/ C1210ES/C1210ESC have the built in inlet filter screen.  See image below as it shows the inlet filter screen where the cold water connection is.

Procedure for Programming The Wireless Remote TSTAT2

The Bosch Wireless Remote Control (TSTAT2) is used to remotely control the temperature of the Bosch Therm tankless water heater. The TSTAT2 does NOT have the ability to remotely reset the Bosch Therm hot water heater. Below is a more in depth procedure for installing the remote control.

The Bosch Wireless Remote Control (TSTAT2) is designed to work with the following Bosch Therm Tankless Water Heaters: C 1210 ESC, C 1210 ES, C 920 ESC, C 920 ES, C 1050 ES, C 800 ES, Integra 500, C 950 ES, 940ES, 940ESO, 715 ES, Evolution 500 and 830ES as well as the Bosch AquaStar 2700ES and 2400ES heaters.

TSTAT2 Remote Control Installation:

On the "heater" control panel, press and hold Program key while
pressing the ON/OFF button to ON.  Release program key when LCD
displays “188”.  LCD shows “P2”. If not, repeat previous step.

1. Press the + button on the heater to select "P3".  Press and hold Program 
key again for 1 sec.  LCD shows one number and one rotating digit. If not, 
repeat previous step.

The number represents the remote control which is to be registered, the
first remote control will be registered with number “0”, the second with
number “1” and so on.  The rotating digit shows that the electronics is 
expecting a registration and waiting for response from wireless remote.  
If the LCD fails to show a number and rotating digit after repeated attempts, 
double check the wire connections made in section 5.1.

2.  Hold wireless remote control in front of the control panel on the heater and
simultaneously press remote control buttons until the temperature indication 
is shown on the remote control LCD.

3.   Press ON / OFF button on the front of the heater to OFF position and then
back ON.

4.  Press buttons + or - on the remote to reach desired temperature.

New remote control is programmed.

To program a 2nd or 3rd remote to the same heater, follow the steps above and 
then after the remote is programmed you will be able to use the first or 2nd or 
3rd remote to raise or lower the temperature on the heater.  Please remember
the remotes cannot be used to reset the heater if an error code should appear.

Service Bulletins for Older Bosch Aquastar Gas Tankless Water Heaters

Bosch has a series of service bulletins for the older retail model Bosch Aquastar and also the compact models such as the 1600P & 1600H.  These service bulletins can be very helpful with installation questions and when having issues with the Bosch tankless water heater.

Service bulletins can help with fixing an issue or with servicing your Bosch tankless water heater.  Please keep in mind and be safe when working on a gas appliance.  You can also contact Bosch directly or have you service agent contact Bosch technical support at 800-642-3111.

Link to:
G3 Service Bulletins for GWH 2700 ES and GWH 2400 ES

CT Service Bulletins for GWH 1000 P, 1600 P, 1600 H

G2 Service Bulletins for GWH 2400 ES/ESO, 250SX/SXO

AquaStar 38B, 125 Series Gas Tankless

AquaStar VP Series Service Bulletins

 AquaStar 240FX Service Bulletins 

Bosch Aquastar 250SX/250SXO Water Valve with Engine

The Bosch Aquastar model 250SX/250SXO water valve with engine part number 8708505018 (old part number 8708505016) is the replacement watervalve for all Bosch Aquastar model 250SX/250SXO tankless water heaters.

This is also the replacement water valve for the Bosch Aquastar 2400E tankless water heater.

Bosch AquaStar 2400E / 2400EO / 250SX / 250SXO Heat Exchanger

The Bosch AquaStar 2400E / 2400EO / 250SX / 250SXO Heat Exchanger Part 8705406285 is the replacement heat exchanger for all Bosch AquaStar 2400E, 2400EO, 250SX and 250SXO tankless water heaters.

This part is also the replacement Heat Exchanger for the Bosch ProTankless 635ES and 635ESO tankless water heaters.