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8. Draw a horizontal line on Diagram A or B that passes through the point located in step 5. The
position of the point along this line relative to the left and right borders of the region it falls into
indicates the relative position that the balance weight of the VRV should be adjusted to. If the
point falls near the leftward border of a region, then the VRV balance weight should be adjusted to
it's minimum position. This corresponds to turning the balance weight screw as far counter-
clockwise as possible.
EXAMPLE:
An oil fired appliance firing at 1.0 gph where the CAS unit needs to be placed 30
equivalent feet from the intake hood.
From Diagram A or B, the point at 1.0 gph on the "Oil Firing Rate" scale and 30
equivalent feet falls in the "4 inch Duct, Hood, and Orifice Ring" region. The point
is in between the left and right boundary of the region. The left boundary is the
edge of the graph, the right boundary is the diagonal line that says "4 inch Duct,
Hood & Orifice Ring." Therefore, place the Orifice Ring into the inlet on the CAS
so that it sits on the ledge above the fan. It does not matter which way the Orifice
Ring is turned as long as it is pushed down against the ledge completely. Use 4"
diameter pipe to connect the vent hood and the CAS unit. Install a VRV and the
included 4x6 Increaser on top of the CAS unit and adjust the balance weight to
3/4 of the distance of it's full adjustment range from it's minimum setting. The
minimum setting is with the balance weight turned all of the way counter-
clockwise.
Total Input of
Appliance
Maximum Equivalent Feet of Installation
4” Duct And Hood
W/Restrictor
4” Duct And 4”
Intake Air Hood
6” Duct And 6”
Intake Air Hood
CAS-3
Oil (gph)
HI
LOW
HI
LOW
HI
LOW
0.50 300
300
300
300
300
300
0.75 300
300
300
300
300
300
0.90 300
220
300
220
300
300
1.00 174
108
232
118
300
300
1.25 99
48
152
63
300
300
1.35 52
14
102
32
300
300
1.55 20
NA
68
13
300
239
1.75 NA
NA
45
NA
300
150
2.00 NA
NA
16
NA
300
53
2.50 NA
NA
NA
NA
193
8
2.75 NA
NA
NA
NA
109
NA
3.25 NA
NA
NA
NA
56
NA
Table 1
