Pentair ETi 400 Installation And User Manual page 29

Direct Air Intake Duct with 4-inch or 6-inch PVC Pipe (Indoor Installation)
For indoor heater installations, the heater is tested for a direct air intake duct using 4 in or 6 in PVC pipe. If outside air is
drawn through 4 in or 6 in PVC duct directly into the heater, vent pipe can be installed in accordance with the following
requirements, see Table 4 below.
The air intake opening MUST be installed at least 1 ft. above the roof line or normal snow levels for free air flow. The
Category IV exhaust vent termination cap must have at least 3 ft. (1 m) minimum vertical clearance from air intake duct,
see Figure 22.
Combustion Air Intake (Vertical or Horizontal) Duct Requirements*
* Combustion Air Intake (Vertical or Horizontal)
Maximum length in Feet (m)
No. of 90° Elbows 4-in (10 cm) pipe 6-in (15 cm) pipe
0 120 ft. (36.6 m)
1 108 ft. (33 m)
2 96 ft. (29.3 m)
3 84 ft. (26 m)
4 72 ft. (22 m)
Table 4.
Flue Exhaust Vent Cap
provided with heater
Flue Exhaust Side
Wall Vent Cap
provided with heater
Figure 22.
Rev. C 4/2017
300 ft. (91.4 m)
288 ft. (87.7 m)
276 ft. (84.1 m)
264 ft. (80.4 m)
252 ft. (76.8 m)
4" or 6" PVC Pipe
Direct Air Intake kit
(P/N 475971)
ETi 400 High Efficiency Pool and Spa Heater Installation and User's Guide
Section 2: Installation Instructions
CAUTION
Do NOT combine exhaust vent pipes to a
common exhaust vent in multiple unit
installations. Run separate vent pipes.
4" or 6" PVC Pipe
29
provided with heater