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 Therm 660EF/660EFO Remote Controller

The Bosch Therm 660EF/660EFO Wired Remote Controller, part number BRC01US is specifically designed for the Bosch Therm 660EF/660EFO units.  The wired remote gets wired to the Bosch 660EF/660EFO unit using 18 ga wire and can be installed up to 300' maximum away from the heater.

The wired remote should be installed in a location that is accessed easy from the main point of hot water use such as on the bathroom wall.  The default setting for the 660EF/660EFO is 120° F.  For most residential applications, the recommended setting is 120° F. 125° water is scalding and is very dangerous.

The Bosch Therm 660EF/660EFO gas tankless water heaters come with wired, marked connectors in the unit by the main control board.  The wired connectors are marked, 120°, 130°, 140° and 160°.  You must have the remote controller to achieve the 160° temperature. 

The remote control comes with many special options.  The remote control will give error codes on the display in the event of a problem (refer to the service manual or contact Bosch Technical Support for error codes and troubleshooting).  The upper limit of the hot water supply temperature can be changed to 100°F, 105°F, 110°F, 115°F, 120°F, 125°F, 130°F, 135°F, 140°F and up to 160 with the remote control.  There is also a unique flow meter alarm setting on the remote control.

The flow meter alarm setting can be used to set a desired amount of gallons of water maximum that is normally used.  As an example:  say your bath tub holds 50 gallons of hot water.  You can press and hold the flow meter alarm until it starts flashing and then set the remote to a maximum of 42 gallons of water.  So when you go and fill the bathtub with hot water and once the remote senses it has flowed 42 gallons of water an alarm will sound and then you would have to physically go and shut the water off at the source.  The alarm will stop after 10 seconds.

Bosch Therm 660EF / 660EFO Tankless Water Heater Sale

For a limited time the Bosch Therm 660EF indoor tankless water heaters and Bosch Therm 660EFO outdoor tankless water heaters are on sale for a special low price. The Bosch 660EF/EFO heaters are 140,000 BTU direct vent tankless water heaters and they are available in both natural gas and propane models. They require 120V power for the fan forced exhaust.

The Bosch Therm 660EF indoor tankless water heaters require 3" single-wall stainless steel vent pipe and are designed to be vented either through the roof or out the side wall.

The following four models are available for same-day shipping:

• Bosch Therm 660EF-NG (Natural Gas)
• Bosch Therm 660EF-LP (Liquid Propane)
• Bosch Therm 660EFO-NG (Natural Gas)
• Bosch Therm 660EFO-LP (Liquid Propane)

Check out our special discounted pricing as these heaters are available at this reduced pricing while supplies last.

Also consider purchasing the following:

• Webstone EXP2 Isolation Valve Kit 44443PR
• Bosch Therm 660EF Remote Control
• 3" Stainless Steel Venting

Bosch Therm 520PN & 520HN vs Bosch Therm 660EF

This blog entry compares the Bosch Therm series 520PN & 520HN models to the Bosch Therm 660EF heater.  The Bosch Therm 520PN & 520HN gas tankless water heaters are 117,000 BTUs as the Bosch Therm 660EF is 140,000 BTUs.  These tankless water heaters are designed for 1 major application at a time such as 1 shower at a time or maybe 2 small sinks at once. They all are available in natural gas or propane models.

The Bosch Therm 520 PN, 520HN and the 660EF all take thier combustion air from the space where they are installed in.  You will want to make sure you refer to the installation manual for these units and make sure you have enough combustion air for the area where these are to be installed.  You can always consult a HVAC technician to calculate and make sure you have enough air supply.  These units should NEVER be installed in a bathroom or bedroom where the door is normally kept closed as the heaters while running would deplete the oxygen from the room causing illness and death.  This statement is on the front of the heaters and also noted in the installation manual.  The National Fuel Gas Code states this also but the installer would also want to go by local code.

The Bosch Therm 520PN has a standing pilot light and is a naturally drafting unit as the P stands for standing pilot and the N stands for naturally drafting.  The Bosch Therm 520HN has a hydro generator ignition and is a naturally drafting unit as the H stands for Hydro generated and the N stands for naturally drafting.  The Bosch Therm 660EF requires power and plugs into 120V outlet.  The 660EF has electronic ignition and is fan assisted which makes it a direct vent unit and the E stands for electronic ignition and the F stands for fan assisted.

The Bosch Therm 520PN and the Bosch Therm 520HN both use an exhaust vent of 5" diameter double wall type B-vent and should be vented vertically up through the roof for a minimum of 6' to the raincap.  There is a vertical vent kit called the H/P VVT Vertical Vent kit and has all the material for penatrating the roof.  If venting the 520PN or 520HN up through the roof is not an option then the heaters could be vented horizontally out the sidewall but MUST use the AQ4 Powervent kit.  The 660EF is a direct vent unit and requires to be vented verically or horizontally with 3" stainless steel sealed vent pipe.  The 660EF requires a 660EF adapter first on top of the heater to accomadate the venting.

There is also the Bosch Therm 660EFO Outdoor unit and it is just the same as the 660EF but is designed specifically for outdoor installations.  The 660EFO has a special top that it exhausts out of and also has the electronic ignition and is fan assisted.  The Bosch Therm 660EF/EFO heaters plug into a 120V outlet.

Gas Conversion of Pro Gas Tankless Water Heaters

Some of the Bosch Professional gas tankless water heaters can be converted from one gas type to the next, i.e. from Natural Gas (NG) - Liquid Propane (LPG) and also from LPG - NG.  The Gas Conversion Kit, part #8719002176 includes a jumper for placement on the control board, a set of instructions for calibrating the gas and air mix and also some stickers to be placed on the heater stating it has been converted. 

The tools required for the gas conversion are:

• Flat and Phillips Screwdrivers
• #40 torx driver
• Digital CO2 Gas Combustion Analyzer
• This procedure must be performed by a licensed gas technician

The Bosch Professional Non-condensing heaters such as the 940ES/940ESO/830ES/715ES/635ES and the Evolution 500 CAN be converted using the gas conversion kit.

All of the Bosch Therm condensing heaters such as the C1210ESC/C1210ES/C1050ES/C950ES/C800ES and Integra 500 CANNOT be converted as the units have a special plate built into the burner tray.  This extra plate in the burner tray was designed and instlled to give the heater the ability to be installed at higher elevations up to 8000'.

Also the Bosch Therm 660EF/660EFO/520PN/520HN/425HN/425EF/330PN CANNOT be converted as they are not designed at all for gas conversion.

Bosch Therm 660EF/660EFO Tankless Water Heaters

The new Bosch Therm 660 EF and Bosch 660 EFO are direct vent units.  These units take thier combustion air from the area they are installed in.  The 660EF/EFO are compact in design for space saving installations and are only 14" x 20 1/2" x 7".  The 660EF/EFO are designed and approved for reciculation and space heating applications.  The units have electronic ignition and come equipped with built in freeze protection.  The Bosch Therm 660EF vents either vertically or horizontally using 3" or 4" stainless steel venting #AL29-4C. 

The 660EF is manufactured in Japan and comes with a different vent connection than the 830ES, 940ES, etc.  The 660EF needs to be vented with single wall stainless steel venting and is designed to connect directly to "Bosch Vent".  However, a Z-Vent adapter (Part # 2SVSWB03) allows for the use of 3" Z-vent stainless venting to be used.  Global Pro Tankless Supply carries the adapter and all the Z-Vent stainless steel venting to install the Bosch Therm 660EF.  We are the exclusive distributor for the AQ5EF Side-wall Vent Kit for the Bosch 660EF tankless water heater.

The Bosch Therm 660EFO outdoor unit comes ready for installation and does not require any additional cap or venting.

Without the Z-Vent adapter (Part # 2SVSWB03), the customer would have to purchase different venting ("Bosch Vent") to use for the 660EF.

The Bosch Therm 660 EFO is our most compact outdoor model and is loaded with features you’d expect from Bosch, including freeze protection and built-in high temperature capability (160°F).

The Bosch Therm 660 EFO is a good replacement for the GWH425HNO and the 125BO as these units have been discontinued. 

The Bosch Therm 660EF and Bosch Therm 660EFO have an excellent warranty:

• 15 year limited warranty on heat exchanger; 3 year warranty if used in direct recirculating applications

• 15 year warranty on heat exchanger if used if recirculated through a storage tank such as the Ariston mini-tank

• 5 year warranty on all other parts