Calculating Equivalent Feet - Lochinvar POWER VENTED GAS HEATERS Installation And Operating Manual

Calculating Equivalent Feet

WATER HEATER
HEATER INPUT
MODEL (Btu/hr)
40 & 50 gal. 40,000
60 gal. 42,000
40 & 50 gal. 50,000
40 & 50 gal. 40,000
60 gal. 42,000
40 & 50 gal. 50,000
50 gal. (short) 62,000
50 gal. (tall) 65,000
75 gal. 72,000
40 & 50 gal. 40,000
60 gal. 42,000
40 & 50 gal. 50,000
50 gal. (short) 62,000
50 gal. (tall) 65,000
75 gal. 72,000
Equivalent lengths of straight pipe for various elbows using Schedule 40 PVC, CPVC and polypropylene.
Size
2" (50mm)
3" (76mm) 90° elbow
4" (102mm)
2" (50mm)
3" (76mm) 45° elbow
4" (102mm)
COVER PLATE
(OPTIONAL)
TERMINATION
ELBOW
RODENT
SCREEN
(INSTALL INTO
ELBOW)
12" (305mm) MIN. OR
Example for calculating equivalent feet.
ABOVE ANTICIPATED
Section "A"
SNOW LEVEL.
90° elbow
Section B
45° elbow
Section C
45° elbow
Section D
Total Equivalent 34.0 ft.
GROUND LEVEL
Based on this example use the (fully open) rodent
screen for vent length greater than 20 equivalent ft.
(6.1 equivalent metres) (see Figures 32 & 33).
32
VENT SIZE PRESSURE
(Inside SWITCH
Diam) SETTING
- 0.27 in. w.c.
2" (50mm) - 0.27 in. w.c.
- 0.37 in. w.c
- 0.27 in. w.c.
3" (76mm) - 0.27 in. w.c.
- 0.37 in. w.c.
- 0.99 in. w.c.
3" (76mm) - 0.99 in. w.c.
- 0.99 in. w.c.
- 0.27 in. w.c.
4" (102mm) - 0.27 in. w.c.
- 0.37 in. w.c.
- 0.99 in. w.c.
- 0.99 in. w.c.
4" (102mm)
- 0.99 in. w.c.
Short Sweep/
Type
Short Radius
8 ft. (2.44m)
4 ft. (1.22m)
Note: The vent pipe must be supported every 4 ft. (1.2M). To prevent vibration and sagging, it is recommended
to use isolation pads when attaching straps to fl oor joists, walls or ceilings. PVC and CPVC vent pipe should be
sloped upwards away from the blower assembly at a pitch of 1/8 in. (3mm) rise per 4 ft. (1.2M). Polypropylene
vent systems require a 1/4" (6mm) per 1 ft. (0.3M) upward slope to ensure proper drainage.
0.5 ft. (0.15m)
8.0 ft. (2.44m)
1.0 ft. (0.31m)
4.0 ft. (1.22m)
1.5 ft. (0.46m)
4.0 ft. (1.22m)
15.0 ft. (4.57m)
(10.37m)
MAXIMUM EQUIVALENT
VENT LENGTH
50 ft. (15.2m) +
termination elbow
125 ft. (38.1m) +
termination elbow
50 ft. (15.2m) +
termination elbow
180 ft. (54.9m) +
termination elbow
125 ft. (38.1m) +
termination elbow
Long Sweep/ Notes:
Long Radius 1. Use long radius elbows where
5 ft. (1.52m)
2. Venting systems may use a maximum
2.5 ft. (0.76m)
3. Use proper screen termination (see
Table 2
STRAP
Figure 34
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MINIMUM EQUIVALENT
VENT LENGTH
7 ft. (2.1m) +
termination elbow
7 ft. (2.1m) +
termination elbow
7 ft. (2.1m) +
termination elbow
125 ft. (38.1m) +
termination elbow
50 ft. (15.2m) +
termination elbow
possible. Minimum distance between
90º elbows should be 6" (150mm)
wherever possible.
of fi ve (5) 90° elbows.
Figures 32 & 33).
45° SHORT
ELBOW
90° SHORT
ELBOW