Bosch PROTANKLESS GWH 345/450 ESR - Manual (Page 18)

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18
Installation instructions
3.6.3 Condensate drain requirements
An external condensate drain must always be installed
except when using one 90° elbow and less than 3 feet
of horizontal pipe.
Note: condensate must be disposed of according to
local codes.
1. Install condensate drain as close to heater as
possible.
2. Use 3/8" ID high temperature silicone tube to
connect to condensate drain port. Do not use copper
piping for any portion of the condensate drain.
3. Form a condensate trap by means of a 3" loop
partially filled with water to form a gas trap. Add small
amount of mineral oil if the trap is drying out.
4. To increase the tube length, connect to end of the
high temperature silicone tubing with vinyl tubing,
PVC or CPVC pipe. Do not reduce the internal
diameter at any point.
Fig. 17 Required condensate drain installation
3.6.4 Room sealed installation (Twin pipe)
Although it is permitted to draw combustion air from
inside, the recommended method is to provide
combustion air through a 3" pipe from the outside. See
Chapter 3.5 for more direction on combustion air.
To reduce pressure differentials between the exhaust
and combustion air intake, it is required that both
terminators exit on the same wall or roof. See Fig. 18 for
an example horizontal twin pipe termination and Fig. 19
for the vertical twin pipe termination example. Use only
approved rain caps. For vertical air inlets use 2 90°
elbows with opening facing down and covered with a
screen.
Fig. 18 Horizontal twin pipe termination
Fig. 19 Vertical twin pipe termination
6 ft
2 ft