S256~7~8~9 Instruction Manual

Types S256 — S259

Instruction Manual Type S256, S257, S258, & S259 Gas Regulators Form 5137, June 1980

WARNING Fisher regulators must be installed, operated, and maintained in accordance with ferderal, state, and local codes, rules regulations, and Fisher instructions.

If the regulator vents gas or a leak develops in the system, service to the unit may be required. Failure to correct trouble could result in a hazardous condition.

Call a gas servicman to service the unit. Only a qualified person must install or service the regulator.

Figure 1. Typical S256 Series Gas Regulator

INSTALLATION WARNING

INTRODUCTION Scope of Manual This instruction manual provides instructions and a parts list of Types S256, S257, S258, S259 gas service regulators.

Personal injury or system damage may result if this regulator is installed, without appropriate overpressure protection, where service conditions could exceed the limits shown in tables 1, 2, and 3 for a given construction.

Regulator installations should be adequately protected from physical damage.

Description These regulators are typically used at homes to reduce intermediate gas distribution pressures down to a reduced pressure range of 4-1/2” to 20” W.C. (5 springs). All units have a low pressure shutoff mechanism that minimizes the possiblity of gas escaping through unlighted pilots or open buners. Type S257 and S259 have meter bar body construction, and Type S256 and S257 have an internal relief valve.

Specifications Table 1 lists the specifications for the regulators. The following information is stamped on the regulator at the factory: type number, seat ring size, spring range, and date of manufacture.

©Fisher Controls Company, 1980

All vents should be kept open to permit free flow of gas to the atmosphere. Protect openings against entrance of rain, snow, insects, or any foreign material that may plug the vent or vent line. On outdoor installations, point the spring case vent downward to allow condensate to drain. This minimizes the possibility of freezing and of water or other foreign materials entering the vent and interfering with proper operation.

Under enclosed conditions of indoors, escaping gas may accumulate and be an explosion hazard. In these cases, the vent should be piped away fom the regulator to the outdoors.

Types S256 — S259 Table 1. Specifications

BODY SIZES AND END CONNECTION

NPT screwed inlet and outlet 3/4, 3/4 x 1 inchn 1 inch n 3/4 x 3/4 x 3/4 x 3/4, 3/4 x 1 x 1 x 1 inch n 1 x 1 x 1 x 1 inch

MAXIMUM ALLOWABLE INLET PRESSURES

See table 2

MAXIMUM EMERGENCY OUTLET PRESSURE

15 psig (Spring case pressure)

MAXIMUM ALLOWABLE OUTLET PRESSURE

3 psi above outlet setting

OUTLET PRESSURE RANGE

4-1/2" to 20" W.C. (11.2 to 49.8 millibar)

SEAT RING DIAMETERS

3/16", 1/4", and 5/16 inches

TEMPERATURE CAPABILITIES

-20° to +170° F (-29° to 77° C)

PRESSURE REGISTRATION

Internal

APPROXIMATE WEIGHT

2 pounds (.9 kg)

Before installing the regulator, check for damage which might have occurred in shipment. Also check for dirt or foreign matter which may have accumulated in the regulator body or in the pipeline. Apply pipe compound to the male threads of the pipeline and install the regulator so that flow is in the direction of the arrow cast on the body. The meter bar body is designed to mount atop a gas meter, see figure 2. Apply pipe compound to the male threads of the pipeline and install the regulator so that flow is in the direction indicated by the arrow cast on the body.

The spring case can be rotated to any of the positions shown in figure 3 by removing the casing screws and placing the vent in the desired position.

Do not install the regulator in a location where there can be excessive water accumulation, such as directly beneath a down spout or in an undrained pit. Replace the regulator if water gets into the spring case or the lower casing of the regulator.

Figure 2. S257 or S259 Meter Bar Installation

It is advisable that the downstream piping be the same size as the regulator outlet for a minumum distance of 18” or to the meter inlet.

Series 250 regulators have either a 1/4” or 3/4” FNPT spring case vent. It is screened to prevent insects or foreign material from entering. On indoor installations, the vent should be piped to the outside of the building. Remove the retaining ring and screen from the regulator vent connections and connect vent piping from that connection to the outdoors.

Vent piping should be of as large a diameter as practicable, be as short as possible, and have a minimum number of bends and elbows. Install a weather and insect resistant vent assembly on the outside end of the pipe, such as Fisher Type Y602 series. The same installation precautions apply to vent assemblies as the integral regulator vents covered above.

A program of regulator inspection of the vent opening should be established to see that it has not become plugged by

2

Figure 3. Various Vent Positions of S256 Series foreign material. On some installations, such as in areas of heavy snow fall, it may be necessary to install the regulator beneath a protective hood. If other protection is provided from the elements, the vent should be pointing or sloping down sufficiently to allow any condensate to drain. Also check the regulator periodically for external or internal corrosion.

Types S256 — S259 Table 2. Inlet Pressure SEAT RING SIZE Inches

mm

3/16 1/4 5/16

OPTIMUM INLET PRESSURE*

MAXIMUM INLET PRESSURE

3/4" Body

3/4" Body

1" Body Psig

Bar

Psig

Bar

1" Body

Psig

Bar

Psig

Bar

4.8

40

2.8

60

4.1

60

4.1

60

4.1

6.4

30

2.1

40

2.8

40

2.8

40

2.8

7.9

30

2.1

30

2.1

30

2.1

30

2.1

*Do not exceed these pressures if high capacity relief (3/4" vent) is required on S256 and S257

Table 3. Spring Chart SPRING RANGE

3. Slowly open the downstream shutoff valve.

PART NUMBER

COLOR CODE

11.2 - 13.7 12.4 - 18.7 17.4 - 29.9

1J3174 2712 1J7890 2702 1C6005 2702

Green Yellow Red

27.4 - 34.9 27.4 - 49.8

0N0394 2702 1B4136 2702

Cadmium Cadmium

Inches W.C.

Millibar

4" - 5" 5" - 12" 7" - 12" 11" - 14" 11" - 20"

OVERPRESSURE PROTECTION WARNING Some type of overpressure protection is needed if actual inlet pressure can exceed the outlet pressure rating. Overpressuring any portion of this equipment above the limits given in tables 1, 2, and 3 may cause damage to regulator parts, leaks in the regulator, or personel injury due to bursting of pressure - containing parts or explosion of accumulated gas.

To avoid overpressure, provide appropriate overpressure protection to ensure that none of the inlet or outlet pressure limits will be exceeded. External downstream overpressure protection is required on Types S258 and S259 because these units do not have an internal relief valve. Regulators should be inspected for damage after any overpressure condition.

4. Check all connections for leaks.

Adjustment To increase the outlet pressure setting of the regulator , the adjusting screw (key 5, figure 5 or 6) must be turned clockwise.

This requires removal of the closing cap (key 3). To reduce the outlet pressure setting, turn the adjusting screw counterclockwise. A pressure gauge should always be used to monitor downstream pressure while adjustments are being made. Do not adjust the spring to produce an outlet pressure setting above the limit stamped on the closing cap. If the required pressure setting is not within the range of the spring being used, substitute with the correct spring, see table 3. When changing the spring, also change the range stamped on the closing cap to indicate the actual pressure range of the spring in use. After the spring adjustment has been completed, replace the closing cap.

SHUTDOWN Installation arrangements may vary, but in any installation It is important that the valves be opened or slowly and that the outlet pressure be vented before venting inlet pressure to prevent damage caused by reverse pressurization of the regulator. The steps below apply to the typical installation as indicated.

1. Slowly close the upstream shutoff valve

STARTUP

2. The back disc assembly in th eregulator will shut off as inlet pressure drops. Upstream and downstream pressure can be bled off.

CAUTION Pressure gauges should always be used to monitor downstream pressure during start-up.

1. Slowly open the upstream shutoff valve.

2. The low pressure shutoff mechanism has to be reset. To do this, remove the closing cap (key 3, figure 5 or 6) and pull quickly upward on the reset stem (key 9).

Note Follow the same procedure if the regulator shuts off during service.

PRINCIPLE OF OPERATION Refer to figure 4. When downstream demand decreases, the pressure under the diaphragm increases. This pressure overcomes the regulator setting (which is set by a spring).

Through the action of the pusher post assembly, the valve disc moves closer to the seat ring andreduces gas flow. If demand downstream increases, pressure under the diaphragm decreases. Spring force pushes the pusher post assembly downward, the valve disc moves away from the seat ring, and the gas flow increases.

3

Types S256 — S259 Disassembly to Replace Diaphragm

RESET STEM

RELIEF VALVE MAIN VALVE DISC DIAPHRAGM BACK DISC

INLET PRESSURE OUTLET PRESSURE

SEAT RING

Figure 4. Operational Schematic of Types S256 - S259 Regulators As downstream pressure drops under high demand, the diaphragm will drop to its lowest position and the main disc will move to its farthest position from the seat ring. This allows the spring in the back disc assembly to seat the back disc against the seat ring and shut off flow. This condition is maintained until the regulator is manually reset by quickly pulling upward on the reset stem in the spring case.

The back disc assembly will also close if inlet pressure drops too low, even if demand is not high.

The Type S256 and S257 regulators include an internal felief valve for over pressure protection. If the downstream pressure exceeds the regulator setting by approximately 7" to 16" W.C. (depending on the main spring used), the relief valve opens and exess gas is vented through the stabilizer vent in the upper spring case.

MAINTENANCE WARNING To avoid personel injury or equipment damage, do not attempt any maintenance or disassembly without first isolating the regulator from system pressure and relieving all internal pressure as described in "shutdown".

Regulators that have been disassembled for repair must be tested for proper operation before being returned to service. Only parts manufactured by Fisher should be used for repairing Fisher regulators. Relight pilot lights according to normal startup procedures.

Due to normal wear or damage that may occur from external sources, this regulator should be inspected and maintained periodically. The frequency of inspection and replacement of parts depends upon the severity of service conditions or the requirments of local, state, and federal rules and regulations. refer to figure 5 or 6.

4

1. Remove the closing cap (key 3) and adjusting screw (key 5).

2. Take the spring case screws (key 17) out of the spring case (key 2) and remove the spring case and spring (key 6).

3. Lift the diaphragm assembly (key 10), and slide it away from the lever (key 11) so that the pusher post (key 7) releases the lever.

4. On S258 and S259, remove the reset stem (key 9, figure 6) holding the pusher post cap (key 19(. On S256 and S257, remove the reset stem (key 9, figure 5) and take off the spring retainer (key 34) and relief valve sspring (key 8).

5. The diaphragm and diaphragm heasd assembly (key 10) can be removed and replaced with new parts.

6. Reassemble in the reverse order of the above procedures. Before tightening the reset stem (key 9) into the pusher post (key 7) to secure the new diaphragm, place the loosely assembled diaphragm and head unit into position in the body, being sure the pusher post is properly hooked on the lever (key 11). Rotate the diaphragm so the diaphragm and body holes align. Tighten the reset stem and proceed with reassembly.

CAUTION Before tightening the spring case screws (key 17), replace the spring and adjusting screw. Turn the adjusting screw to about mid position. This will stretch the oversized diaphragm to ensure slack in the assembled diaphragm. The slack created by this method is necessary for good regulation. Be sure the diaphragm does not fold over at the flange when reassembling.

Disassembly to Replace Valve Discs and Seat Ring 1. Insert a 5/8" thinwall socket through the body inlet onto the seat ring (key 16) and unscrew.

2. To examine the shutoff inner valve (key 25), remove the retaining ring (key 28) and take out the valve guide (key 26), spring (key 27), and inner valve.

3. Insert a 1/2" thinwall socket onto the valve disc assembly (key 15) and unscrew.

4. Replace the valve disc, seat ring, or inner valve if they are nicked, cut, or otherwise damaged.

5. Reasemble inb reverse order of the above procedure.

Treat the male threads of the new seat ring with pipe compound before reassembling.

ORDERING PARTS The type number, seat ring size, and date of manufacture are stamped on the closing cap. Always provide this information in any correspondence with your Fisher representative regarding replacement parts or technical assistance. If construction changes are made in the field, be sure that the closing cap is also changed to reflect the most recent construction.

Types S256 — S259

Figure 5. Type S256

Figure 6. Type S259

5

Types S256 — S259 Key

PARTS LIST Key 1

2

3 4 5 6

Description

Part Number

7

Part Number

Body, aluminum S256 & S258: 3/4" T40078 3/4" x 1" T40079 1" T40080 S257 & S259: 3/4" x 3/4" x 3/4" x 3/4" 3J3832 3//4" x 1" x 1" x 1" 3J3833 1' x 1" x 1" x 1" 3J3831 Spring Case, aluminum 1/4" vent T40101 3/4" vent T10671

Description

08012 08012 08012

08012 08012 08012 08012 000A2

Closing Cap, plastic Zinc 1J3165 44012 Gasket, rubber 1E1056 06992 Adjusting Screw, Plastic T10071 06642 Spring, Spring wire, See table 3

Pusher Post, Aluminum 2H9656 08012 8 Relief Valve Spring, Music wire S256 & S257 T10416 37022 9 Reset Stem, steel S256 & S257 1J3164 25062 S258 & S259 1J3179 28992 10 Diaphragm assembly 1H9664 000A2 10A* Diaphragm Synthetic Rubber 1H9663 02082 10B Diaphragm Head Steel 1H9659 11042 11 Valve Lever Steel 1H9662 25062 12 Pin, SST 1E9837 35032 13 Screw, steel, (2 req'd) 1E9854 28982 14 Valve Stem, Assembly 1H9666 000A2 15 Disc Holder Assembly 1J3163 000A2

Key

Description

Part Number

16* Seat Ring, aluminum 3/16" T20556 09012 1/4" T20557 09012 5/16" T20558 09012 17 Screw, steel (8 req'd) 1B2856 28982 18 Vent screen, 1/4", Monel 0L0783 43062 19 Pusher Post cap, steel S258 & S259 1H9660 25062 22 Vent Screen, 1/4" SST 1B6335 38392 23 Snap Ring, 3/4" vent only, SST T10669 24152 25 Inner Valve, Steel 1J3167 000A2 26 Valve Guide, SST 1J3171 09062 27 Spring, SST 1J3175 37022 28 Retaining Ring, Steel 1D8077 28992 34 Spring Retainer, steel S256 & S257 T10073 24152 35 Pad, S258 & S259 T12461 T0012

*Recommended Spare Parts

FISHER CONTROLS COMPANY, INC. LIMITED ONE-YEAR WARRANTY

This warranty applies only when the product is used for consumer use within the United States and is installed and used in accordance with all applicable national, state and local codes, regulations and laws.

The owner's responsibility is for normal maintenance, servicer's travel and labor charges.

This warranty shall not apply of the product has been subjected to unreasonable use, negligence, accident in transit, alteration, improper

installation or misapplication.

FISHER shall not be liable for any default or delay in performance under this warranty caused by any contingency beyond its control, including without limitation, war, government restrictions or restraint, strikes, fire, flood, or a short or reduced supply of raw material.

THERE ARE NO EXPRESS WARRANTIES OTHER THAN SET FORTH ABOVE. ALL IMPLIED WARRANTIES, INCLUDING THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE LIMITED TO THE DURATION OF THE EXPRESS WARRANTIES SET FORTH ABOVE. LIABILITY FOR CONSEQUENTIAL DAMAGES UNDER THIS WARRANTY IS EXCLUDED TO THE EXTENT EXCLUSION IS PERMITTED BY LAW.

Specifications are subjuect to change.

Fisher Controls Fisher Controls Company, Marshalltown, Iowa,.

Metric equivalents of English units are shown in parentheses and are in millimeters unless otherwise noted.

Printed in U.S.A.

FISHER warrants the product identified hereon to be free from defects in material and workmanship under normal use and service. If, within one year from the date the product is shipped from the factory, any part fails because of a manufacturing defect, FISHER will provide a free replacement part for any defective or malfunctioning part, FOB McKinney, Texas.