Replacement Parts

87
|
HYDRONIC SOLUTIONS CATALOG
CBV BALANCING WHEEL
CBV FLOW MEASUREMENT | SUBMITTAL
Job:
Representative:
Engineer:
Contractor:
Order no: Date:
Submitted by: Date:
Approved by: Date:
1 Measure the dierential pressure (  p) across ports a & b
(fig. 1) of the ARMflo cbv.
2
Using the cbv Rule, turn the wheel of the slide rule
(fig. 2) until the measured pressure drop appears in
window. For example, for the slide rule shown in fig. 2,
the wheel is turned reveal 3.00 in the window.
3
Read the flow for the particular size of valve installed.
In this case, the reading
for a O" valve would be
5.96 USgpm.
4
The flow calculation for
other valve sizes appear
on either side of the
center rivet.
5
In the event that the calculated flow is not within the
desired range, turning the handle clockwise will decrease
the flow and turning the handle anticlockwise will increase
the flow.
Alternatively, or if a more precise flow rate calculation is
required, use the flow rate formula and corresponding Cv
value for the cbv model measured.
Flow rate = 0.66 Cv
Flow rate : USgpm
 P: Dierential pressure (ft of h
2
o)
D: Density of liquid (lb/ft
3
)
D/62.4: 1 for water at 60°f (16°c)
0.66: Conversion constant
Cv : cbv flow co-ecient
ARMflo Circuit Balancing Valves (cbv)
include an integral venturi for dieren-
tial pressure to flow rate correlation.
Compared to traditional variable orifice
valves, the handle turns position is not
required for flow rate calculation.
The venturi design also results in higher
flow measurement accuracy (especially
when throttled), correctly indicates
valve plugging conditions, and enables
faster and move accurate flow mea-
surement, CBV adjustment, system
balancing and troubleshooting.
Accurate balancing contributes to
greater occupant comfort, system
eciency and life expectancy.
½"-2" circuit balancing valves
CBV size (inches)
CBV size (inches)
CBV Rule
Armstrong Circuit Balancing Valves include an integral fixed orifice
venturi for dierential pressure to flowrate correlation.
Compared to traditional variable orifice valves, the handle
turns position is not required for flow rate calculation.
This design enables faster and more accurate flow
measurement, cbv adjustment, system balancing and
troubleshooting.
Accurate balancing contributes to greater
occupant comfort, system eciency and
life expectancy.
Flow Rate = 0.66C
V
∆P/(d/62.4)
instructions (For balancing purposes only)
Use Armstrong performance curves for valve pressure drop determination
and size selection.
1. Measure the dierential pressure across ports a & b of the cbv.
2.
Slide the wheel to the nearest corresponding value in the ∆ p(ft) window.
3. Read the flow rate conversions (feet to USgpm) in the red USgpm
window for the cbv model measured.
Alternatively, or if a more precise flow rate calculation is
required, use the flow rate formula and corresponding
Cv value for the cbv model measured.
flow rate: USgpm
∆P: dierential pressure (ft)
d: density of liquid (lb/ft
3
)
d/62.4: 1 for water at 60˚f (16˚c)
0.66: conversion constant
Cv: cbv flow co-ecient
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Valve handwheel setting
instructions
1. Place hairline over valve setting opposite cbv size.
2. Read flow rate (gpm) opposite meter gauge reading.
USgpm
size
Cv
USgpm
size
Cv
Flow Rate for O"
cbv = 5.96 USgpm
Flow Rate for other
sizes between ½"
and 2" sizes
Δp = 3.0 ft
 P/(d/62.4)
fig. 1
fig. 2
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