MN801GAS 060520
– 8 –
2. Prepare site • assemble burner • mount burner
(continued)
Table 2
Minimum combustion chamber dimensions
Combustion chambers should be sized as recommended in
Table 2A and 2B. They should be constructed of refractory
materials with the capacity to withstand 2600°F or higher.
It is difficult to include all possible chamber constructions in this
manual. Therefore, you should use the information presented
in this manual combined with commonly practiced techniques
when determining chamber design. If certain conditions are in
question, consult the factory.
Using chamber linings
1.
When using refractory liners or lightweight chambers, use insulating-
type refractory rated 2600°F minimum, or as specified by the appliance
manufacturer.
2.
You must install a target wall liner if flame length is close to the length
of the chamber.
3.
Use a floor liner when possible. The floor liner will improve firing in most
applications. Extend floor liner 3 to 4 inches up the side walls.
4.
Target wall liners — Extend target wall liners at least 3 to 4 inches above
the center of the flame corbel the top 1½ to 2½ inches deep.
5.
Use preformed chamber liners when available. Lining the floor and tar-
get wall water-backed combustion chambers with lightweight insulating
refractory will accomplish the same.
6.
When converting coal-fired units, install a combustion chamber in the
ashpit area, or fill the ashpit with sand up to 2 inches above the “mud
ring” of the boiler (firing through the door). Install a lightweight refractory
liner on the target wall.
Air tube insertion length (UTL)
1.
Insertion air tube length (UTL) is the distance from mounting
flange to end of air tube. Verify that the end of the air tube will be
flush with, or no more than ¼ inch short of, the inside of the appli-
ance combustion chamber front wall when the burner is mounted.
NOTE: Mounting flange spacer is available for appliances with a UTL <4"
(consult factory for part #).
TABLE 2A 801GAS
MINIMUM DIMENSIONS RECOMMENDED IN REFRACTORY
COMBUSTION CHAMBERS–(Inches)
1
Gas
MBH
2
Length
L
3
Width
W
4
Dimens.
C
5
Suggested
Height
H
6
Minimum
Dia.
Vertical
Cyl.
11.4
12.0
12.6
13.2
13.2
14.4
15.0
15.6
16.2
16.8
17.4
33
34
35
36
38
39
40
41
43
44
46
15
16
16
17
17
18
18
19
19
20
20
7.5
8.0
8.0
8.5
8.5
9.0
9.0
9.5
9.5
10.0
10.0
15
16
16
17
17
18
18
19
19
20
20
31
32
33
34
36
37
38
39
41
42
44
TABLE 2B 801GAS
MINIMUM DIMENSIONS RECOMMENDED BOILERS FIRED
WITHOUT COMBUSTION CHAMBERS–(Inches)
1
Gaz
MBH
2
L
With
Target
3
L
Withou
Target
4
Width
W
5
Dimens.
C
6
Dimens.
D
11.4
12.0
12.6
13.2
13.8
14.4
15.0
15.6
16.2
16.8
17.4
33
34
35
36
38
39
40
41
43
44
46
38
39
40
41
43
44
46
47
49
50
52
17
18
18
19
19
20
20
21
21
22
22
7.5
8.0
8.0
8.5
8.5
9.0
9.0
9.5
9.5
10.0
10.0
9.5
10.0
10.0
10.5
10.5
11.0
11.0
11.5
11.5
12.0
12.0
