Rheem 136-1826 User Manual
Page 9
COMBUSTIBLE CONSTRUCTION CLEARANCES
The water heater should be positioned to provide the minimum clearances from combustible surfaces and to
provide sufficient space for servicing the unit as follows.
MINIMUM CLEARANCES:
PROTECTED SURFACES
Clearances to surfaces installed
in rooms which are large (2) in
comparison with size of heater.
Rear
12"
9
6
4
6
4
4
4
4
Left Side
12"
9
6
4
6
4
4
4
4
136
Right Side
6"
5
3
3
6
2
3
3
3
Indoor Top
42"
42
42
42
42
42
42
42
42
Rear
12"
9
6
4
6
4
4
4
4
Left Side
12"
9
6
4
6
4
4
4
4
181-399 Right Side
12"
9
6
4
6
4
4
4
4
Indoor Top
39"
39
39
39
39
39
39
39
39
Outdoor Top(1)
Rear
12
9
6
4
6
4
4
4
4
Left Side
18
12
9
6
6
6
6
6
6
512-825 Right Side
6
5
3
3
6
2
3
3
3
Indoor Top
36
36
36
36
36
36
36
36
36
Outdoor Top
(1)
Rear
24
16
12
8
8
8
8
8
8
Left Side
24
16
12
8
8
8
8
8
8
926-1826 Right Side
24
16
12
8
8
8
8
8
8
Indoor Top
24
24
24
24
24
24
24
24
24
Outdoor Top
(1)
(1) Unobstructed.
(2) Large rooms are defined as having a volume at least 16 times the total volume of the heater.
(3) Installation clearances for heaters in rooms not large in comparison with the heater size shall be as listed
under combustible surfaces and shall not be reduced by the protection methods.
SERVICING CLEARANCES:
24" in front of heater for removal of burner tray.
18" on side opposite water connection for deliming of Heat Exchanger on
Models 181-1826 only.
Combustible Surfaces
(a) 3 1/2-in. thick masonry wall with- out ventilated air space
(b) 1/2-in. insulation board over 1-in. glass fiber or mineral wool batts
(c) 0.024 sheet metal over 1-in. glass fiber or mineral wool batts reinforced with wire on rear face with ventilated air space
(d) 3 1/2-in. thick masonry wall with venti-
lated air space
(e) 0.024 sheet metal with ventilated air
space
(f) 1/2-in. thick insulation board with ventilated air space
(g) 0.024 sheet metal with ventilated air space over 0.024 metal with ventilated air space
(h) 1-in. glass fiber or mineral wool batts sandwiched between two sheets 0.024 sheet metal with ventilated air space
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