Installation Guide

30
WATER
HEATER
MODEL
HEATER
INPUT
(Btu/hr)
VENT
SIZE
(Inside
Diam.)
PRESSURE
SWITCH
SETTINGS (“ w.c.)
2 PIPE MAX.
EQUIV. VENT
LENGTH
2 PIPE
MIN. EQUIV.
VENT LENGTH
CONC. VENT
MAX. EQUIV.
VENT LENGTH
CONC. VENT
MIN. EQUIV.
VENT LENGTH
N.O. N.C.
40 gal. 40,000
2”
-0.32 -2.12
50’ + term. elbow
and screen*
7’ + term. elbow
and screen*
50’ + term. elbow
and screen*
7’ + term. elbow
and screen*
50 gal 45,000
40 gal. 40,000
3”
-0.32 -2.12
125’ + term. elbow
and screen*
7’ + term. elbow
and screen*
100’ + term. elbow
and screen*
7’ + term. elbow
and screen*
50 gal 45,000
50 gal.
3”
50’ + term. elbow
and screen*
58,000
(L.P.)
-1.25 -1.42
30’ + term. elbow
and screen*
62,000
-1.35 -1.66
75 gal.
76,000
-1.25 -1.42
40 gal. 40,000
4”
-0.32 -2.12
180’ + term. elbow
and screen*
50’ + term. elbow
and screen*
N/A N/A
50 gal 45,000
50 gal.
125’ + term. elbow
and screen*
58,000
(L.P.)
-1.25 -1.42
62,000
-1.35 -1.66
75 gal.
76,000
-1.25 -1.42
* see Figure 36 and Figure 37
Equivalent lengths of straight pipe for various elbows using Schedule 40 PVC, CPVC, ABS, and polypropylene.
Vent
Pipe
Size
Elbow
Type
Short
Sweep/
Radius
Long
Sweep/
Radius
Notes:
1. Vent lengths shown do not include vent termination elbow.
2. A horizontal vent must have a 45° or 90° vent termination elbow to direct the vent pipe
downward unless otherwise specified by local requirements.
3. A vertical vent must have a 90° elbow to direct the vent pipe horizontally followed by a
vent termination 45° elbow to direct the vent pipe downward unless otherwise specified
by local requirements.
4. If additional elbows are used in the vent system the allowable vent lengths are reduced.
5. Two 45° elbows are considered the equivalent of one 90° elbow.
6. The equivalent length of the sound suppressor is 15’ .
2”
3"
4"
90° 8’ 5’
2”
3"
4"
45° 4’ 2.5’
Table 4.
Use the appropriate vent termination screen as shown in Figure 36 & Figure 37. Install the vent termination screen in
both the air intake pipe and the exhaust pipe.