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 ProTankless 425PN Heat Exchanger

The Bosch ProTankless 425PN Heat Exchanger Part 8705406386 (87054063860, 8-705-406-386-0) is the current replacement heat exchanger for allBosch ProTankless 425PN tankless water heaters.

Please note that the original heat exhanger for all Bosch ProTankless 425PN tankless water heaters was 8705406275 (87054062750, 8-705-406-275-0). This part is now obsolete and has been replaced by the 8705406386 heat exchanger.

Bosch Therm 520HN NG & LP Tankless Water Heater

The new Bosch Therm 520HN comes set for either NG (Natural Gas) or LP (Liquid Propane).  The 520HN has a hydro ignition and is a naturally drafting heater and requires no power to operate.  This unit is basically for 1 major application at a time such as 1 shower at a time.  The Bosch 520 HN Needs to be vented vertically with a 5" B-vent up through the roof for a minimum of 6' to the raincap.  If the heater has to be vented out the sidewall then you must use the AQ4 Powervent kit and this kit would require 110V power.  The gas connection at the bottom of the heater is a standard 3/4" connection.

The new Bosch Therm 520HN is a direct replacement for many of the older model heaters.  Below is a list of the units that the 520HN would replace.  Please keep in mind to always be aware of gas line sizing and the length of the gas line run.

The Bosch Therm 520HN could replace:

Bosch 1600P or 1600H: (If either one of these units was vented horizontally out the sidewall with the AQ4 powervent kit then that same AQ4 powervent kit can be used for the new Bosch Therm 520HN)

Bosch Aquastar 125B, 125X, 125HX, 425PN or the 425HN: (If any of these units was vented horizontally out the sidewall with the AQ1 powervent kit then that AQ1 powervent kit WILL NOT work for the new Bosch Therm 520HN.  You would need to install the new AQ4 powervent kit for the new Bosch Therm 520HN)

ELM Le Blanc 170VP or 125VP:  (If either one of these units was vented horizontally out the sidewall with the AQ1 powervent kit then that AQ1 powervent kit WILL NOT work for the new Bosch Therm 520HN.  You would need to install the new AQ4 powervent kit for the new Bosch Therm 520HN)

The Bosch Therm 520HN is a direct replacement for the older tankless water heaters listed above but you still always want to make sure and refer to the installation manual and follow the gas line sizing chart and venting requirements.  Please also refer to local code for all other restrictions and approvals.

Bosch Therm 520PN NG & LP Tankless Water Heater

The new Bosch Therm 520PN comes set for either NG (Natural Gas) or LP (Liquid Propane).  The 520PN has a standing pilot and is a naturally drafting heater and requires no power to operate.  This unit is basically for 1 major application at a time such as 1 shower at a time.  The Bosch 520 PN Needs to be vented vertically with a 5" B-vent up through the roof for a minimum of 6' to the raincap.  If the heater has to be vented out the sidewall then you must use the AQ4 Powervent kit and this kit would require 110V power.  The gas connection at the bottom of the heater is a standard 3/4" connection.

The new Bosch Therm 520PN is a direct replacement for many of the older model heaters.  Below is a list of the units that the 520PN would replace.  Please keep in mind to always be aware of gas line sizing and the length of the gas line run.

The Bosch Therm 520PN could replace:

Bosch 1600P or 1600H: (If either one of these units was vented horizontally out the sidewall with the AQ4 powervent kit then that same AQ4 powervent kit can be used for the new Bosch Therm 520PN)

Bosch Aquastar 125B, 125X, 125HX, 425PN or the 425HN: (If any of these units was vented horizontally out the sidewall with the AQ1 powervent kit then that AQ1 powervent kit WILL NOT work for the new Bosch Therm 520PN.  You would need to install the new AQ4 powervent kit for the new Bosch Therm 520PN)

ELM Le Blanc 170VP or 125VP:  (If either one of these units was vented horizontally out the sidewall with the AQ1 powervent kit then that AQ1 powervent kit WILL NOT work for the new Bosch Therm 520PN.  You would need to install the new AQ4 powervent kit for the new Bosch Therm 520PN)

The Bosch Therm 520PN is a direct replacement for the older tankless water heaters listed above but you still always want to make sure and refer to the installation manual and follow the gas line sizing chart and venting requirements.  Please also refer to local code for all other restrictions and approvals.

Bosch Therm Tankless Product Number Changes

Recently Bosch has changed their naming strategy for the Bosch Therm line up of Tankless Water Heaters. Previously, the Bosch part numbers reflected the flow rate at a 45 degree F temperature rise; now the part numbers reflect the flow rate at a 35 degree F temperature rise.

So, for example, the legacy Bosch Pro 920ES is now the Bosch Therm  C 1210ES. This means that this heater can produce 9.2 GPM of hot water at a 45 degree F rise and 12.1 GPM at a 35 degree F rise.

This naming change was done, so it seems, to align Bosch with an emerging industry de facto standard of showing the flow rate at a 35 degree F temperature rise. In reality, showing the flow rate at a 45 degree F temperature rise made more sense as a 45 degree F temperature rise is more realistic average across the US. However, with other manufacturers advertising their heaters 35 degree F flow rate, it appeared that their tankless water heaters had a higher flow rate (which was of course not true).

So, now Bosch's published flow rates allow for easier comparisons to those of other manufacturer's heaters.

Bosch did make some upgrades to the new models, so actually the newer heaters have more capabilities than their older legacy heaters. More about those details in later blog entries...

Here is a brief listing of the name changes:

• Old: Bosch Pro 920ES  |  New: Bosch Therm C 1210ES
• Old: Bosch Pro 920ESC  |  New: Bosch Therm C 1210ESC
• Old: Bosch Pro 800ES  |  New: Bosch Therm C 1050ES
• Old: Bosch Pro 715ES  |  New: Bosch Therm 940ES & Bosch Therm 940ESO
• Old: Bosch Pro 425HN  |  New: Bosch Therm 520HN
• Old: Bosch Pro 425PN  |  New: Bosch Therm 520PN
• Old: Bosch Pro 260PN  |  New: Bosch Therm 330PN

The part numbers for the Bosch Electric whole-house and point-of-use tankless water heaters did not change, nor did the Ariston Pro Ti names change.

Call us for pricing on any of the new Bosch Therm Tankless Water Heaters at 866.289.4652.

Global ProTankless Supply