Bosch Therm C 1210 ES Installation And Operating Instructions Manual page 27

WARNING:
▶ Do not install condensate drain tubing in areas where it may
freeze.
The condensate must be disposed of in accordance with local
codes.
See chapter 4.11 "Filling the condensate trap".
Use materials approved by the authority having jurisdiction. In
the absence of other authority, PVC, and CPVC pipe must
comply with ASTM D1785, F441 orD2665. Cement and
primer must comply with ASTM D2564 or F493. For Canada,
use CSA or ULC certified PVC or CPVC pipe, fittings and
cement, see table 5.
Appliance condensate drain installation
The appliance comes equipped with an internal condensate
drain and siphon. This drains condensation formed in the
secondary heat exchanger. Piping must be installed under the
condensate drain outlet on the water heater and piped for
disposal in accordance with local codes.
Fig. 20 Appliance drain installation
[1] Leave minimum ¼" air gap
[2] Trap required
[3] 1 ½" x ½" PVC reducer
C 1210ES/ESC – 6 720 644 887 (2022/04)
External condensate drain installation
If an external condensate drain (installer supplied) must be
installed (chapter 4.3.2), the following is recommended:
• 1. Install condensate drain on a horizontal section of the
exhaust pipe as close to the heater as possible.
• 2. The condensate must be disposed of according to local
codes.
• 3. To install condensate drain in vent system, use PVC 3" X
3" X 1.5" tee (part# 196278) and reduce for drain
connection
Fig. 21 External condensate drain installation
[1] Condensate drain
[2] Dispose of condensate in accordance with local codes
[LA] Minimum 4"
4.3.6 Freeze prevention
In cold climates, components of a tankless water heater can
freeze and burst from negative draft. A leading cause of
negative draft is combustion appliances in the building not
being supplied with sufficient combustion air. A wood stove or
furnace can pull its combustion air from the water heater's vent
pipe, allowing the cold incoming air to freeze the cold water in
the heat exchanger. Supplying more combustion air for all
combustion appliances is the solution. A HVAC specialist
should be consulted to design solutions for providing more
combustion air.
Listed below is an additional measure designed to further limit
backdraft in extreme conditions assuming all other possible
causes have been addressed.
Backdraft reducer
The Heat Fab backdraft reducer (9301BFP) is the preferred
option for limiting backdraft (see fig. 22).
Installation instructions
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