Field Controls SWG Stainless Series Manual page 3

8. Air fl ow adjustment MUST be made to ensure appliance effi ciency. This should be done at the appliance
exhaust outlet with a velocity meter, draft gauge, or by "match test procedure". A match test is in accordance
with National Fuel Gas Code ANSI Z223.1, Section 8.6.
9. On oil-fi red and gas-fi red heating appliances not equipped with a draft hood, a barometric draft control MUST
be installed to regulate proper air fl ow and fl uctuations in the system's air fl ow during operation. Fluctuations
may come from wind loads on the outlet of the power venter, house de-pressurization during windy days,
and the diff erent house ventilation requirements between summer and winter operation. For gas appliances,
use a Field Controls Type MG-1 Barometric Draft Control. For oil appliances, use a Field Controls Type M or RC
Barometric Draft Control. Gas-fi red draft induced systems should have a single-acting barometric draft control
installed.
INSTALLATION OF SWG POWER VENTER
Table 1
OIL GAS
MAX* MAX**
OIL GPH BTU/HR
INPUT INPUT
N/A 70,000
1.10 170,000
1.85 290,000
2.65 416,000
3.60 566,000
4.75 740,000
*Rating at 100 psi. Sizing based on appliance maximum input rate not actual fi ring rate.
**Do not exceed maximum BTU/HR input rating or maximum oil GPH input. For multiple venting system applications, add the input for
each appliance. Category I gas-fi red draft induced systems require an SWG-4HD or larger. Category III gas-fi red draft induced systems
require an SWG-5 or larger.
PROCEDURE FOR CALCULATING TOTAL EQUIVALENT PIPE LENGTH IN FEET
1. Calculate the total equivalent feet for each type of fi tting used in the venting system from Table 2.
2. Calculate the total amount of feet for the straight lengths of vent pipe.
3. Add the equivalent feet for the fi tting with the total amount of feet of straight lengths. This will
approximate the total equivalent feet of the vent system.
UNIT SIZING CHART
MAXIMUM EQUIVALENT FEET OF VENT PIPE
AT MAX BTU/HR AT 60% OF MAX BTU/HR
INPUT
21
50
---
---
35
65
16
51
95
28
68
100
28
61
90
26
51
70
page 3 of 12
VENTING WITH
INPUT VENT PIPE SIZE
80
100
---
23
100
100
44
100
100
78
100
100
78
100
100
72
100
100
MODEL
3"
4" SWG–3
---
3"
SWG–4HD
4"
SWG–4s
5"
4"
SWG–5
5"
SWG–5s
6"
5"
SWG–6
6"
SWG–6s
7"
6"
7" SWG–7
8"
7"
8" SWG–8
9"
P/N 46139100 Rev P 08/19