The replacement heat exchanger for the Bosch Protankless 715ES has a new part number of 87054064220. This part number has changed from the original part number of 8705406356. The heat exchanger part number 87054064220 is also the replacement for Bosch Therm 830ES, 940ES, 940ESO and the Bosch Evolution 500.
This replacement heat exchanger is also good for the retail heaters Bosch 2400ES/2700ES.