Bosch 2700ES / 2400ES Condensation and Rain Strategies

The Bosch 2700ES / 2400ES tankless water heaters do NOT come with built-in condensation drains.

The Bosch 2700ES / 2400ES Installation Manuals states that the Bosch 2700ES / 2400ES tankless water heaters requires the installation of an external condensate drain for:

• ALL vertically terminating vent installations;
• All Horizontal terminating vent installations where the total vent length is greater than 10 feet; or
• Vent installations where any section of the exhaust vent pipe passes through an unconditioned space

Bosch recommends to install the condensate drain as close to the heater as possible.

There are three 3" Z-Flex Z-Vent condensation drain parts that you can choose from:

• 3" Vertical Condensation Drain Tee (2SVEVWCF03)
• 3" Horizontal Condensation Drain Pipe (2SVEDWCF03)
• 3" Vertical Condensation Drainpipe (2SVEVDP03)

Each of these will require a Condensate Drain Kit (2SVEDTK24).

The 3" Vertical Condensation Drain Tee (2SVEVWCF03) acts as a 90 degree elbow and is the best choice for catching condensation and rain as it has a large reservoir.

Not all horizontal installations have an opportunity to use the 3" Vertical Condensation Drain Tee and they should therefore use the 3" Horizontal Condensation Drain Pipe (2SVEDWCF03) to replace a straight section of pipe.

The 3" Vertical Condensation Drainpipe (2SVEVDP03) has the least capacity for removing condensation and rain. It should be used as a last resort and only when 3" venting goes literally straight up from the heater. It is preferable to offset the Bosch 2400E from the vertical vent pipe and use the 3" Vertical Condensation Drain Tee (as a 90 degree elbow) along with an actual 90 degree elbow.

If you must go straight up from the Bosch 2700ES / 2400ES / 2400E heaters, we recommend that you use the 3" to 4" Increaser (2SVSI0304) and then run 4" Z-Flex Z-Vent venting. This will allow you to use the larger 4" Vertical Condensation Drainpipe (2SVEVDP04). This 4" drainpipe has a much higher capacity for removing condensation and rain than does the 3" drainpipe.

Steve