Bock Water heaters OT300-A Installation And Operation Instruction Manual page 12

SECTION IV: INSTALLATION (cont.)
VENT & COMBUSTION AIR INTAKE (cont.)
Installations in Canada must conform to the requirements of CSA B149 code. Plastic
vent systems must be assembled with pipe, fittings, cements, and primers listed to ULC
S636. Components of this listed system shall not be interchanged with other vent
systems or unlisted pipe/fittings. In Canada, the primer and cement must be of the
same manufacturer as the vent system; do not mix primers and cements from one
manufacturer with a vent system from a different manufacturer. The supplied plastic
pipe/fittings are certified as part of the water heater.
Minimum and Maximum System Lengths
The water heater should be located such that plastic vent pipe lengths and the number of
connection fittings are minimized. Minimum and maximum equivalent pipe lengths for
the vent and combustion air intake systems are given in Tables 4 and 5. Either 4 in. or 6
in. plastic piping may be used. The water heater is provided with fittings that readily
adapt to 4 in. plastic pipe. DO NOT use less than 4 in. diameter plastic pipe and DO NOT
use unequal sizes except as shown to increase from 4 in. to 6 in. diameter at the point of
connection to the water heater. Figure 4 shows the proper connections to increase from 4"
to 6" plastic pipe.
Figure 4: Adapting Air Intake and Exhaust Vent for 6" Piping (optional)
NOTE: The equivalent straight pipe length of a 90°, 1/4 standard bend elbow and
a 45°, 1/8 standard bend elbow is 5 feet and 2.5 feet, respectively. DO NOT use
short bend elbows.
NOTE: An elbow used as an exhaust vent termination fitting must be included
when determining the total number of elbows.
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NOTICE