User Guide

page 3
INSTALLATION OF SWG POWER VENTER
UNIT SIZING CHART
OIL GAS MAXIMUM EQUIVALENT FEET OF VENT PIPE
MAX*
OIL GPH
INPUT
MAX**
BTU/HR
INPUT
AT MAX BTU/HR
INPUT
AT 60% OF MAX BTU/HR
INPUT
VENTING WITH
VENT PIPE SIZE
MODEL
N/A 70,000
21 80 3"
SWG–350 100 4"
--- --- ---
1.10 170,000
--- 23 3"
SWGII–4HD
SWG–4s
35 100 4"
65 100 5"
1.85 290,000
16 44 4"
SWGII–5
SWG–5s
51 100 5"
95 100 6"
2.65 416,000
28 78 5"
SWGII–6
SWG–6s
68 100 6"
100 100 7"
3.60 566,000
28 78 6"
SWG–761 100 7"
90 100 8"
4.75 740,000
26 72 7"
SWG–851 100 8"
70 100 9"
Air flow adjustment MUST be made to ensure appliance efficiency. This should be done at the appliance 8.
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.
On oil-fired and gas-fired heating appliances not equipped with a draft hood, a barometric draft control 9.
MUST be installed to regulate proper air flow and fluctuations in the system’s air flow during operation.
Fluctuations may come from wind loads on the outlet of the power venter, house de-pressurization during
windy days, and the different 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-fired draft induced systems should have a single-acting
barometric draft control installed.
Table 1
*Rating at 100 psi. Sizing based on appliance maximum input rate not actual firing 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-fired draft induced systems require an SWGII-4HD or larger. Category III gas-fired draft induced
systems require an SWGII-5 or larger.
PROCEDURE FOR CALCULATING TOTAL EQUIVALENT PIPE LENGTH IN FEET
Calculate the total equivalent feet for each type of fitting used in the venting system from Table 2.1.
Calculate the total amount of feet for the straight lengths of vent pipe.2.
Add the equivalent feet for the fitting with the total amount of feet of straight lengths. This will 3.
approximate the total equivalent feet of the vent system.