Replacement Heat Exchangers Now on Global Protankless Supply

Global Protankless Supply is now carrying the replacement heat exchangers for all the Bosch gas tankless water heaters.  The heat exchangers are made of high quality copper. Below is a list of all the heat exchangers and their current part numbers.  Older part numbers are also listed as part numbers have changed over the years.

Bosch Therm C1210ES / C1210ESC Heat Exchanger Part 8705406419 (87054064190 or 8-705-406-419-0).  This part is also the replacement Heat Exchanger for the older Bosch ProTankless 920ES and 920ESC condensing tankless water heaters.

Bosch Greentherm C1050ES-LP / C950ES-LP (Liquid Propane) Heat Exchanger Part 8738704026 (87387040260 or 8-738-704-026-0).

Bosch Greentherm C1050ES-NG / C950ES-NG (Natural Gas) Heat Exchanger Part 8738704117 (87387041170 or 8-738-704-117-0).

Bosch Therm C1050ES-LP / C950ES-LP (Liquid Propane) Heat Exchanger Part 8705406421 (87054064210 or 8-705-406-421-0).

Bosch Therm C1050ES-NG / C950ES-NG (Natural Gas) Heat Exchanger Part 8738721270 (87387212700 or 8-738-721-270-0).

Bosch Therm 940ES / 830ES Heat Exchanger Part 8738701985 (87387019850 or 8-738-701-985-0). This part is also the replacement Heat Exchanger for the Therm 940ESO, Bosch ProTankless 715ES, Bosch AquaStar 2700ES and 2400ES and the Bosch Evolution 500.  Older part numbers were 8705406422, 87054064220, 8-705-406-422-0, 8705406356, 87054063560, 8-705-406-356-0.

Bosch ProTankless 635ES / 635ESO Heat Exchanger Part 8705406285 (87054062850 or 8-705-406-285-0).  This part is also the replacement Heat Exchanger for the Bosch AquaStar 2400E, 2400EO, 250SX and 250SXO tankless water heaters.

Bosch Therm 520 Heat Exchanger Part 8705406386 (87054063860 or 8-705-406-386-0).  The Bosch Therm 520 Heat Exchanger Part 8705406386 is the replacement heat exchanger for all Bosch Therm 520PN and 520HN tankless water heaters and for all Bosch ProTankless 425PN and certain Bosch ProTankless 425HN (with serial numbers starting 686 and higher) tankless water heaters. It is also the replacement heat exchanger for all Bosch AquaStar 1600P and 1600H tankless water heaters. This heat exchanger replaces the obsolete 8705406275 (87054062750, 8-705-406-275-0) heat exchanger.

Bosch ProTankless 425 Heat Exchanger Part 8705406380 (87054063800 or 8-705-406-380-0).  The Bosch 425 Heat Exchanger is the replacement heat exchanger for the following Bosch ProTankless water heaters: 425EF, 425HN (with serial numbers starting 685 and lower) and 425HNO and the following Bosch AquaStar tankless water heaters: 125B, 125BO, 125BL, 125X, 125HX, 125FX.  This heat exchanger will also work with the following Bosch WR400 series tankless water heaters: WR400-1KV1P23S3100, W400KD5 P23S3100T2, WR400-3K V1B23S3100, WR400-7K V1G23S3195, WR430-3K VM1E23S3190 and WR430-3K VM1E23S3195.  Older part numbers were 8705406235, 87054062350, 8-705-406-235-0.

Bosch Universal Hydro Generator

The Bosch universal Hydro Generator, part number 8707406104 (87074061040 or 8-707-406-104-0) is designed to work with all newer Bosch Therm 520HN heaters as well as all older model hydro generated units.  The universal hydrogenerator comes with miscellaneous water pipes, gaskets and bushings to adapt to the older units. The hydro generator works with water flow and has a small wheel that spins when the water starts to flow. The small wheel inside has a magnet on it that when spinning produces a certain amount of mili volts that is transferred through a couple wires to the ignition unit and that in turn lets the ignition unit light the pilot and then the main burner.  There is no need for any electrical power to operate the heater.

The older units that would require the universal hydro generator are the Bosch model 125HX, 425HN, 425HNO, 1600H and the Bosch WR400 series heater WR400-7K V1G23S3195.  The new universal Hydro Generator part replaces all older hydrogenerators such as 8707406043 (87074060430 or 8-707-406-043-0), 8707426026 (87074260260 or 8-707-426-026-0), 8707406059 (87074060590 or 8-707-406-059-0), 8707406069 (87074060690 or 8-707-406-069-0), 8707406095 (87074060950 or 8-707-406-095-0) and 8707406071 (87074060710 or 8-707-406-071-0).

PCB Control Boards for Powerstream Pro & Bosch Tronic 5000 Electric Tankless

The PCB control board (Printed Circuit Board) is a thermostatically controlled circuit board that allows the whole house electric tankless water heater, models WH17, WH27 & WH36, to be manually controlled by a temperature dial that would range in temperature from 86-131 degrees. The PCB in conjunction with a flow transducer enables the PCB to turn on additional elements in the heater as necessary depending on the amount of gallons per minute (gpm) flowing through the heater.

The PCB would recognize many factors in the function of the heater to maintain a steady temperature and all of this is determined on where the temperature knob is set to, the gpm flowing through the heater, and the temperature of the incoming ground water.

To obtain the maximum heating potential of the Bosch Tronic 5000 electric tankless water heater it must be wired correctly and have the full required voltage to the unit. The Bosch Tronic 5000 WH17 would require 2 independent double pole 40 amp breakers wired with 8 gauge wire and could draw a maximum of 80 amps at full flow through the heater. The WH17 would require the home to be supplied with a minimum of a 150 amp service. The Bosch Tronic 5000 WH27 would require 3 independent double pole 40 amp breakers wired with 8 gauge wire and could draw a maximum of 120 amps at full flow through the heater. The WH27 would require the home to be supplied with a minimum of a 200 amp service.  The Bosch Tronic 5000 WH36 would require 3 independent double pole 60 amp breakers wired with 6 gauge wire and could draw a maximum of 180 amps at full flow through the heater. The WH36 would require the home to be supplied with a minimum of a 300 amp service.

The maximum inlet water temperature allowed into the electric tankless is 86 degrees Fahrenheit.

The Bosch Tronic 5000 WH17, WH27 & WH36 have had many upgrades and engineering improvements over the years. In January 2007 the WH17(RP17PT) & WH27(RP27PT) went from having copper canisters that contain the heating elements to an upgraded Polymer module. The PCB control board was also upgraded to maintain a more steady temperature that works with the heating elements in the polymer modules.

Below are the designated PCB control board part numbers for the units before and after 2007.

Before 2007 with serial #60A 00000 or lower:
Powerstream Pro RP17PT PCB with copper can units, part #93-793777
Powerstream Pro RP27PT PCB with copper can units, part #93-793778

After 2007 with serial number between #60A 80000 - 107:
Powerstream Pro RP17PT PCB with polymer units, part #93-793843
Powerstream Pro RP27PT PCB with polymer units, part #93-793844

Newest Bosch Tronic 5000 units with serial number after 108:
Bosch Tronic 5000 WH17 PCB with polymer units, part #8738701732
Bosch Tronic 5000 WH27 PCB with polymer units, part #8738701738

Bosch Tronic 5000 WH36 PCB with polymer units, part #8738701744

Bosch Tankless Water Heaters with New Built-In External Water Filters

Bosch Thermotechnology is always improving the gas-fired tankless water heaters and has recently improved all the sealed combustion tankless water heaters and have added a new hydraulic block on the bottom of all the units that incorporates a new built in external water filter.

The Bosch Greentherm C950ES and Bosch Greentherm C1050ES condensing heaters were designed with the new hydraulic block and external water filter built in.  The Bosch Therm C1210ES/ESC, Bosch 940ES and the Bosch 830ES have recently had the new hydraulic block and external water filter added.  After Serial number beginning with "301" will have the built in external water filter.

Built-in External Water Filter

All of the older Bosch "Therm" models before serial number 301 had the external water filter, part #8703035356 and was sold as an accessory.

Please contact Global Protankless Supply with any questions at 866-289-4652.

Backdraft Reducer #9301BFP for Bosch Tankless Water Heaters

The Heat Fab backdraft reducer (9301BFP) is the preferred option for limiting backdraft for the Bosch Condensing tankless water heaters (see fig. 22).

Note: The following solution is available only for 3" diameter venting.

In cold climates, components of a tankless water heater can freeze and burst from negative draft. A leading cause of negative draft is combustion appliances in the building not being supplied with sufficient combustion air. A wood stove or furnace can pull its combustion air from the water heater‘s vent pipe, allowing the cold incoming air to freeze the cold water in the heat exchanger. The best prevention for this risk is two pipe venting which draws the appliance combustion air from outside creating a positive pressure inside the unit.

For this solution to be effective, the internal flapper must be 100% closed when the water heater is not running. Refer to Figures 24 and 25 for preferred installation positions in the vent system.

Installation considerations:
• Install damper per the supplied manufacturer‘s instructions.
• The damper is only to be used in the exhaust vent piping.
• Ensure directional arrow on damper label faces in the same direction as exhaust flow.
• If installed horizontally, the axis must be horizontal or slightly pitched up towards termination to ensure damper closes 100% when heater is not running.
• To allow accessibility, damper must not be installed in an enclosed section of vent pipe.
• Do not install damper in unconditioned spaces (e.g. attics) Condensation can build up while the heater is running which can later freeze and potentially block the flapper.

The Bosch C1210ES/ESC, C1050ES & C950ES are all approved to use the Backdraft Reducer. 

Phasing out of Bosch Therm 940ESO Outdoor Unit

Bosch is phasing out the Therm 940ESO model tankless water heater in Natural Gas, Part Number 7738000001 and Liquid Propane, Part Number 7738000002.

Bosch will continue to still make the Bosch Therm 940ES NG & LP tankless water heaters. The Bosch Therm Outdoor Kit (BTOK) will be sold as an accessory for outdoor installations.

The Phase out of the Bosch Therm 940ESO outdoor unit will be immediate. Please see the list below for model numbers, color changes by manufacturing date and BTOK model numbers.

Bosch Therm 940ES NG - #7703311076
Bosch Therm 940ES LP - #7703411073
(Gray Models, FD prior to FD420 - White Models, on or after FD420)

BTOK Outdoor Kit - Gray #7709003913
BTOK Outdoor Kit - White #7736502448

Please call Global Protankless Supply at 866-289-4652 for further questions or ordering.

Bosch Greenstar Intelligent Cascade Module (ICM) #7719003528

Bosch is always working on new ways to improve their products and has recently came out with an Intelligent Cascading Module (ICM) part #7719003528 for the Bosch Greenstar gas-fired wall-hung boilers.  The ICM modules are designed to control cascade systems.  A cascade system is a heating system where several smaller boilers are connected in parallel to achieve higher output.  The Bosch ICM modules are only suitable for controlling Bosch Greenstar boilers with BUS-enabled Heatronic 3 systems.

One Bosch ICM module can control up to 4 Greenstar boilers.  By conecting up to 4 ICM modules, up to 16 boilers can be linked to form a single cascade.  Depending on the heating system controls used, a cascade system with up to 4 or up to 16 boilers can be created.  The maximum number of boilers that can be connected and the number of ICM modules required for the different systems are shown in the table below.