Pentair MT125 - Direct Air Intake Exhaust Duct Using 7.62 CM (3 In) PVC Pipe (Indoor Installation)

MASTERTEMP 125 Pool and Spa Heater Installation and User’s Guide 460906 Rev. D 8/2020
32
Combustion PVC Air Intake 3 in. Pipe
(Vertical or Horizontal)
No. of 90° Elbows Maximum Length in M (ft)
0 (21.3 M) 70 ft.
1 (17.7 M) 58 ft.
2 (14.0 M) 46 ft.
3 (10.4 M) 34 ft.
4 (6.7 M) 22 ft.
15.24 cm (6 in) min.
30.4 cm (12 in) min.
91.44 cm (36 in) min.
30.4 cm (12 in) min.
7.62 cm (3 in)
PVC Pipe
7.62 cm (3 in) PVC Pipe
91.44 cm
(36 in) min.
NOTE:
Each 90-degree elbow reduces the maximum horizontal PVC air intake duct run by 30 cm (12 ft) and each 45-degree
elbow in the PVC air intake duct run reduces the maximum run by 15.3 cm (6 ft) See the Table 1 for the maximum lengths using 90-de-
gree elbows.
WARNING!
DO NOT USE PVC PIPE FOR FLUE EXHAUST VENT. FLUE EXHAUST VENT TEMPERATURES CAN BE IN EXCESS OF 400° F. FLUE
EXHAUST VENT MUST BE CATEGORY I or CATEGORY III METAL VENT.
Direct Air Intake Duct with 7.62 cm (3 in) PVC Pipe (Indoor Installation)
For indoor heater installations where combustion air supply might be insufcient, the MasterTemp 125 Heater is certied for
a direct air intake duct using 7.62 cm (3 in) PVC pipe. If outside air is drawn through 7.62 cm (3in) PVC duct directly into
the heater, PVC pipe can be installed in accordance with the following requirements: The air intake opening MUST be
installed at least 1ft. above the roof line or normal snow levels for free air ow. The Category I or III exhaust vent
termination cap must have at least 3ft.minimum vertical clearance from air intake duct (see Figure 26 below).
Figure 26
Section 1. Installation Instructions