V48A,F,J; V88A,J DIAPHRAGM GAS VALVES
Transformer AT72D: (40 VA) for all V88 models.
126590 Adjustable Bleed Valve Assembly: Consists of
adjustable bleed valve with sleeve and compression nut for
connecting to 1/4 in. tubing; see Fig. 8.
Bleed Orifice: Fixed (see Table 2 for appropriate size):
124674 Orifice: 0.011 in. (0.28 mm) diameter.
122160 Orifice: 0.018 in. (0.46 mm) diameter.
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 Btu/h (Btu per hour) or in cf/h (cubic feet per
2. Call the gas utility for information on (a) the specific
gravity (sp gr) and (b) Btu per cubic feet (Btu/cu ft) for
type of gas used.
3. Find the capacity in cf/h. If the capacity is listed in Btu/h,
convert to cf/h by the following formula.
Capacity in cf/h = Btu/h (from burner nameplate)
4. For gases with specific gravities other than 0.64,
multiply the burner cf/h by the conversion factor in Table
5. Use the corrected burner capacity in cf/h when
determining the gas valve size in Fig. 2.
6. Determine the maximum pressure drop across the
valve, and draw a horizontal line at this pressure in Fig.
Table 4. Conversion Factors.
Type of Gas
7. Draw a vertical line in Fig. 2 at the capacity (cf/h) previ-
ously determined. Use the corrected capacity for a gas
with a specific gravity other than 0.64.
8. Use the valve size at the intersection of the horizontal
and vertical lines. If the intersection is between valve
sizes, use the next higher valve size to the right.
To Size Two Identical Valves Piped in Series
1. Find the cf/h for the type of gas used.
2. Consider both valves as one unit. Determine the total
maximum pressure drop across the unit.
3. Find the pressure drop across the first valve by
assuming it to be 45 percent of the total pressure drop.
4. Find the valve size from Fig. 2.
Btu/cu ft (from gas utility)
Divide cfh by:
5. The second valve will be the same size as the first
When Installing This Product...
1. Read these instructions carefully. Failure to follow them
could damage the product or cause a hazardous
2. Check the ratings given in the instructions and on the
product to make sure the product is suitable for your
3. Installer must be a trained, experienced, flame
safeguard control technician.
4. After installation is complete, check out product
operation as provided in these instructions.
Explosion or Electrical Shock Hazard.
Can cause severe injury, death or property
1. Turn off gas supply before starting installation.
2. Disconnect power supply before beginning
installation to prevent electrical shock and
3. Do not remove seal over valve inlet or outlet until
ready to connect piping.
4. Do not bend tubing at the valve after the
compression nut is tightened because this may
result in gas leakage at the connection.
5. Install valve in a horizontal pipe line in any upright
position with the gas flow in the direction indicated
by the arrow on the casting.
Prepare Piping and Install Valve (Fig. 3)
1. Use new, properly reamed pipe free from chips.
2. Do not thread pipe too far. Valve distortion or
malfunction may result from excess pipe in valve.
3. Apply good quality pipe dope, putting a moderate
amount on the male threads only. If pipe dope lodges on
the valve seat, it will prevent proper closure. If using
liquefied petroleum (LP) gas, use pipe dope resistant to
action of LP gas.
4. Install valve in a horizontal pipe line in an upright
position with the gas flow in the direction indicated by
the arrow on the casting.
5. Apply a parallel jaw wrench only to the flat next to the
pipe being inserted. A wrench applied to the valve body
itself or to the end farthest from the pipe being inserted
may distort the casting, causing a malfunction.
6. The gas flow MUST be in the same direction as the
arrow on the bottom of the valve body.