Installation instructions
Selecting inlet air restrictor
Note: Before installing the combustion air inlet accessory, the appropriate inlet air restrictor must be determined using Tables 6, 7 and 8.
Refer to Fig. 15 for mounting sequence.
BDetermine the total length of the straight sections of 3" stainless steel exhaust and enter that length in line 1.
BCount the number of 90° elbows used and enter that value in line 2.
BCount the number of 45° elbows used and enter that value in line 3.
BFor model GWH 345 ESR, enter a 1 in line 4 for model GWH 450 ESR enter a 1 in line 5.
BRepeat steps 1 through 4 for the 3" intake pipe and enter those values in the intake section.
BAdd the totals from the Exhaust table and the Intake table to determine the equivalent vent length. Use this value in Table 6 to determine which restrictor size to use.
Exhaust
1 | Straight section length | __ x 1 = | ____ |
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2 | 90° elbows (qty) | __ x 6 = | ____ |
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3 | 45° elbows (qty) | __ x 3 = | ____ |
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4 | GWH 345 ESR termination | __ x 15 = | ____ |
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5 | GWH 450 ESR termination | __ x 12 = | ____ |
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6 |
| Total: | ____ |
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Intake |
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1 | Straight section length | __ x .5 = | ____ |
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2 | 90° elbows (qty) | __ x 3 = | ____ |
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3 | 45° elbows (qty) | __ x 1.5 | ____ |
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4 | GWH 345 ESR termination | __ x 6 = | ____ |
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5 | GWH 450 ESR termination | __ x 3 = | ____ |
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6 |
| Total: | ____ |
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7 | Total equivalent vent length = | ____ | |
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Table 6 Determining equivalent vent length (see example in Table 7)
Example
Exhaust
•10 - 3' straight sections
•1 - 1' straight section
Total length 31'
•1 - 90° elbow
•1 - GWH 450 ESR termination.
Intake
•5 - 4' straight sections
•2 - 1' straight sections
Total length 22'
•2 - 90° elbows
•1 - GWH 450 ESR termination.
Example
Exhaust
Straight section length | 21 x 1 = | 21 | |
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90° elbows (qty) | 1 x 6 = | 6 | |
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45° elbows (qty) | 0 x 3 = | 0 | |
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GWH 345 ESR termination | 0 x 15 = | 0 | |
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GWH 450 ESR termination | 1 x 12 = | 12 | |
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| Total: | 39 | |
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Intake |
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Straight section length | 22 x .5 = | 11 | |
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90° elbows (qty) | 2 x 3 = | 6 | |
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45° elbows (qty) | 0 x 1.5 | = | 0 |
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GWH 345 ESR termination | 0 x 6 | = | 0 |
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GWH 450 ESR termination | 1 x 3 | = | 3 |
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| Total: | 20 | |
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Total equivalent vent length = | 59 | ||
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Table 7 Determining equivalent length example
Using table 8, the following restrictors would be required:
•GWH 450 ESR NG - restrictor 55
•GWH 450 ESR LP - restrictor 55.
16 | 6 720 607 909 |
