Filter
Top Products
V4943/V8943B,C,N; V4944/V8944B,C,L,N REGULATING DIAPHRAGM GAS VALVES
65-0214—08 4
Fig. 1. V4943/44 and V8943/44 dimensions in in. (mm).
Gas Valve Sizing
1. Check the burner nameplate for:
a. the type of gas used, and
b. the gas flow capacity. The capacity will be listed in
British thermal units per hour (Btuh) or in cubic feet
per hour (cfh).
2. Contact the local gas utility for information regarding:
a. the specific gravity (sp gr) and
b. the Btu per cubic foot (Btucf) for the type of gas used.
3. Find the capacity in cf/h. If the capacity is listed in Btu,
convert to cf/h using the following formula:
4. For gases with specific gravities other than 0.64, multiply
the burner cf/h using the proper conversion factor in
Table 4.
Table 4. Gas Conversion Factors.
5. Use the corrected burner capacity in cfh when determin-
ing the gas valve size in Figs. 2–9.
6. Determine the maximum pressure drop across the valve
and draw a vertical line at this pressure in Figs. 2–9.
7. At the point of intersection of the vertical line and the
curve, draw a horizontal line to intersect the flow
(capacity) scale. The point of intersection indicates the
capacity that can be obtained with the maximum
pressure drop.
8. If the capacity at the maximum pressure drop is
insufficient, use the capacity vs. pressure drop curve for
the next larger valve size and repeat steps 6 and 7.
Fig. 2. Capacity vs. pressure drop of Natural Gas
curves for 1 in. valve.
6-9/16 (167)
FOR 1, 1-1/4
OR
7-3/8 (187)
FOR 1-1/2, 2
SIDE VIEW
6 (152)
6
(152)
TOP VIEW
M23375
ATMOSPHERIC
PRESSURE
REFERENCE
PORT WITH
INTERNAL
VENT LIMITER
OUTLET
PRESSURE
TAP
INLET
PRESSURE
TAP
PRESSURE
REGULATOR
ADJUSTMENT
CAPS
Capacity in cfh = Btuh (burner nameplate)
Btu/cf (gas utility)
Type of Gas sp gr (average) Multiply cfh by
Manufactured 0.60 0.968
Mixed 0.70 1.046
LP-Propane 1.53 1.546
LP-Butane 1.98 1.759
M23376
1 INCH V4/8944B/N REGULATION AREA
0.1
1
10
100
FLOW NATURAL GAS (CFH)
PRESSURE DROP (IN. WC)
100
1000
10000
PO < 2.5 IN.
ANY PO
PO > 2 IN.