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
