Instruction Manual

Note
The main poppet will not open if valve
outlet piping is not closed off so that
the outlet pressure can approach
tank pressure.
Once the main poppet opens, a flow greater than
the valve’s excess flow spring rating or a sufficient surge
in flow forces the main poppet closed against the excess
flow spring (view #4). The pilot valve allows a small
amount of product to bleed, but much less than view #2
where the rapid equalization portion of the stem is placed
in the pilot opening. When the operating lever is moved to
the closed position, the valve closes completely and seals
tightly (view #1).
Installation
Mounting and Piping
The internal valves can be installed in either a half or full
coupling. Excess ow spring closing ow rates vary in half and
full couplings, refer to the Specication section.
1. The pressure/temperature limits in this Instruction Manual and any applicable standard or code limitation should not be exceeded.
2. Product has passed Fisher
®
testing for leakage down to -40ºF / -40ºC.
Kalrez
®
is a mark owned by E.I. du Pont de Nemours and Co.
Types C471, C477 and C486
2
Specications (continued)
Body Size and End Connection Styles
Types C471 and C477
Inlet: 2 or 3-inch MNPT / DN 50 or 80
Outlet: 2 or 3-inch FNPT / DN 50 or 80
Type C486
Inlet: 3-inch CL300 RF Flange / DN 80
Outlet: 3-inch FNPT / DN 80
Number of Outlets
Type C471: 2 (side and straight through)
Types C477 and C486: 1 (straight through)
Excess Flow Springs
Type C470 Half Coupling and Type C486 Flows:
2-inch Sizes / DN 50: 105, 150 and 250 GPM / 397, 567
and 946 L/min
3-inch Sizes / DN 80: 160, 265, 375 and 460 GPM / 605,
1003, 1419 and 1741 L/min
Type C470 Full Coupling Flows:
2-inch Sizes / DN 50: 60, 80 and 130 GPM /
227, 302 and 492 L/min
3-inch Sizes / DN 80: 120, 230, 320 and 380 GPM / 454,
870, 1211 and 1438 L/min
Maximum Allowable Inlet Pressure
(1)
400 psig / 27.6 bar WOG
Temperature Capabilities
(1)(2)
-20 to 150°F / -29 to 66°C
Approximate Weights
2-inch Sizes / DN 50:
Type C471: 11 pounds / 5.0 kg
Type C477: 9 pounds / 4.1 kg
3-inch Sizes / DN 80:
Type C471: 21 pounds / 10 kg
Type C477: 16 pounds / 7.3 kg
Type C486: 20 pounds / 9.1 kg
Construction Materials
Ductile Iron: Body (Types C471 and C477)
Stainless steel: Stem Assembly, Excess Flow Spring,
Spring Seat, Closing Spring, Disc Holder, Disc Retainer,
Screw, O-ring Seat, O-ring Retainer, Cotter Pin, Spring,
Shaft, Screen, Travel Stop, Screen Cap, Bolt, Gasket
and Lock Washer
Steel: Body (Type C486), Cap Screw and
Operating Lever
Plated steel: Nut, Washer, Bonnet Nut, Guide Bracket
and Cap Screw
Polyurethane (PU): Rod Wiper
Polytetrauoroethylene (PTFE): Bushing, Packing
Adaptor and Packing Ring
Nitrile (NBR) (Standard Construction): Main Disc,
Bleed Disc and O-ring
Other Disc Material Available from Factory: PTFE,
Fluorocarbon (FKM), Neoprene (CR), Ethylene-
Propylene (EPDM) and Kalrez
®
Principle of Operation
Refer to the schematic drawing, Figure 2. In view #1, the
valve is held closed by both tank pressure and the valve’s
closing spring. There is no leakage past the resilient seats
in the poppet to the valve outlet.
The valve is opened by moving the operating lever to
approximately mid-point in its 70° travel (view #2). This
allows the cam to place the rapid equalization portion of the
valve stem in the pilot opening, permitting a larger amount
of product to bleed downstream than if the operating lever
were moved to the full open position.
When tank and downstream pressure are nearly equal
after a few seconds, the excess ow spring pushes open
the main poppet (view #3) and the operating lever can be
moved to the full open position.
If tank pressure is greater than the valve’s outlet pressure,
the main poppet will remain in the closed position. If valve
outlet piping is closed off by other valves, however, product
bleeding through the pilot will increase until it nearly equals
tank pressure and the main poppet opens.