S251~S252~S253~S254 Instruction Manual

Type S251—S254

Fisher Controls

Instruction Manual

Type S251, S252, S253 & S254 Gas Regulators

June 1980

Form 5136

WARNING Fisher regulators must be installed, operated, and maintained in accordance with federal, state, and local codes, rules and 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 serviceman to service the unit. Only a qualified person must install or service the regulator.

Figure 1. Typical S251 Series Gas Regulator

INTRODUCTION Scope of Manual This instruction manual provides instructions and a parts list of Types S251, S252, S253, and S254 gas service regulators.

Description These regulators are typically used at homes to reduce intermediate gas distribution pressures down to a reduced pressure range of 3-1/2-inch W.C. to 2-1/2 psig (6 springs).

Type S253 and S254 have meter bar body construction, and Type S252 and S254 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.

regulator is installed, without appropriate overpressure protection, where service conditions could exceed the limits shown in tables 1, 2, 3, and 4 for a given construction. Regulator installations should be adequately protected from physical damage.

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 other 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 or indoors, escaping gas may accumulate and be an explosion hazard.

In these cases, the vent should be piped away from the regulator to the outdoors.

WARNING Personal injury or system damage may result if this

Š Fisher Controls 1980, 1989; All Rights Reserved

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

D400003X012

INSTALLATION

Type S251—S254 Table 1. Specifications BODY SIZES AND END CONNECTION STYLE

NPT screwed inlet and outlet 3/4, 3/4 x 1 inch n 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 tables 2 and 3

MAXIMUM EMERGENCY OUTLET PRESSURE

15 psig (Spring case pressure)

MAXIMUM ALLOWABLE OUTLET PRESSURE

3 psi above outlet setting

OUTLET PRESSURE RANGE

3-1/2" W.C. to 2.5 psig (8.7 millibar to 0.17 bar)

SEAT RING DIAMETERS

1/8, 3/16, 1/4, & 3/8 inches

TEMPERATURE CAPABILITIES

-20° to +170° F (-29° to 77° C)

PRESSURE REGISTRATION

Internal

APPROXIMATE WEIGHT

2 pounds (.9 kg)

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. S253 or S254 Meter Bar Installation

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

Series S250 regulators have either a 1/4 inch or 3/4 inch 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 connection 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 regular inspection of the vent opening should be established to see that it has not become plugged by 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.

2

Figure 3. Various Vent Positions of S251 Series

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, 3, and 4 may cause damage

to

regulator

parts,

leaks

in

the

Type S251—S254 Table 2. Inlet Pressure — 3/4" Body Only SEAT RING SIZE

OPTIMUM INLET PRESSURE* 3.5" - 18" W.C. Outlet

MAXIMUM INLET PRESSURE

1.5 - 2.5 Psig Outlet

3.5" - 18" W.C. Outlet

1.5 - 2.5 Psig Outlet

Inches

mm

Psig

Bar

Psig

Bar

Psig

Bar

Psig

Bar

1/8

3.2

75

5.2

75

5.2

125

8.6

125

8.6

3/16

4.8

20

1.4

20

1.4

40

2.8

100

6.9

1/4

6.4

12

.8

12

.8

20

1.4

75

5.2

3/8

9.5

5

.3

5

.3

8

.6

20

1.4

* Do not exceed these pressures if high capacity relief (3/4" vent) is required on S252 and S254.

Table 3. Inlet Pressure — 1" Body Only SEAT RING SIZE Inches

OPTIMUM INLET PRESSURE* 3.5" - 18" W.C. Outlet

mm

Psig

Bar

MAXIMUM INLET PRESSURE

1.5 - 2.5 Psig Outlet

3.5" - 18" W.C. Outlet

1.5 - 2.5 Psig Outlet

Psig

Bar

Psig

Bar

Psig

Bar 8.6

1/8

3.2

100

6.9

75

5.2

125

8.6

125

3/16

4.8

40

2.8

20

1.4

40

2.8

100

6.9

1/4

6.4

12

.8

12

.8

20

1.4

75

5.2

3/8

9.5

5

.3

5

.3

8

.6

20

1.4

* Do not exceed these pressures if high capacity relief (3/4" vent) is required on S252 and S254.

Adjustment

Table 4. Spring Chart Spring Range

Part Number

Color Code

Inches W.C.

Millibar

3.5 - 5.5 5.25 - 9.25 7 - 14

9 - 14 13 - 23 17 - 35

1J7890 2702 1C6005 2702 1U2580 2702

Yellow Red Olive Drab

10 - 13 12 - 18 1.5 - 2.5 psig

25 - 32 30 - 45 104 - 173

0N0394 2702 1B4136 2702 T10212 2702

Cadmium Cadmium Green

regulator, or personal 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 Type S251 and S253 because these units do not have an internal relief valve. Regulators should be inspected for damage after any overpressure condition.

STARTUP

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 4.

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 closed 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. Open valves downstream of the regulator.

CAUTION

2. Slowly close the upstream shutoff valve.

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

3. Inlet pressure will automatically be released downstream as the regulator opens in response to the lowered pressure on the diaphragm.

1. Check to see that all appliances are turned off.

PRINCIPAL OF OPERATION

2. Slowly open the upstream plug cock.

3. Check all connections for leaks.

4. Light the appliance pilots.

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 disk moves closer to the seat ring and reduces gas flow. If 3

Type S251—S254 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 S251 and S253, remove the screw (key 20, figure 6) holding the pusher post cap (key 19). On S252 and S253, remove the spring holder (key 9, figure 5) and take off the spring retainer (key 34) and relief valve spring (key 8).

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

Figure 4. Operational Schematic of Types S251—S254 Regulators

demand downstream increases, pressure under the diaphragm decreases. Spring force pushes the pusher post assembly downward, the valve disk moves away from the seat ring, and the gas flow increases.

Type S252 and S254 regulators include an internal relief valve for over pressure protection. If the downstream pressure exceeds the regulator setting by 7 inches W.C. to 1 psig (depending on the main spring used), the relief valve opens and excess gas is vented through the stabilizer vent in the upper spring case.

MAINTENANCE WARNING To avoid personal 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 requirements of local, state, and federal rules and regulations.

Refer to figure 5 or 6.

Disassembly to Replace Diaphragm 1. Remove the closing cap (key 3) and adjusting screw (key 5).

6. Reassemble in the reverse order of the above procedures. Before tightening the screw or spring holder (key 9 or 20) 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 screw or 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 with reassembling.

Disassembly to Replace Valve Disk and Seat Ring 1. Insert a 1/2-inch allen wrench through the body inlet into the socket head of the seat ring (key 16) and unscrew.

2. A 1/2-inch thinwall socket can then be inserted through the body inlet to unscrew the valve disk assembly (key 15).

3. Replace the valve disk or seat ring if either is nicked, cut, or otherwise damaged.

4. Reassemble in the 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, spring range, 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.

4

Type S251—S254

Figure 5. Type S252

Figure 6. Type S253

5

Type S251—S254

PARTS LIST Key

Description

Key 6

Part Number 7

1

2

3 5

Body, Aluminum S251 & S252: 3/4" T40078 08012 3/4" x 1" T40079 08012 1" T40080 08012 S253 & S254: 3/4" x 3/4" x 3/4" x 3/4" 3J3832 08012 3/4" x 3/4" x 1" x 1" 3J3833 08012 1" x 1" x 1" x 1" 3J3831 08012 Spring Case, aluminum 1/4" vent T40101 08012 3/4" vent T10671 000A2 Closing Cap, plastic T10072 06992 Adjusting Screw, All springs except T10212 T10071 06642 For T10212 1H9657 44012

8

9 10* 10A* 10B 11 12 13 14 15*

Description

Part Number

Spring, spring wire, See table 4 Pusher Post, Aluminum 2H9656 08012 Relief Valve Spring, Music wire S252 & S254 1H9672 37022 Spring Holder, steel S252 & S254 1F4942 24132 Diaphragm Assembly 1H9664 000A2 Diaphragm, Synthetic Rubber 1H9663 02082 Diaphragm Head, Steel 1H9659 11042 Valve Lever, Steel 1H9662 25062 Pin, SST 1E9837 35032 Screw, steel, (2 req'd) 1E9854 28982 Valve Stem Assembly 1H9666 000A2 Disk Holder Assembly 1H9668 000A2

Key 16*

17 18 19 20 22 23 34 35

Description

Part Number

Seat Ring, aluminum 1/8" 1H9675 09012 3/16" 1H9676 09012 1/4" 1H9677 09012 3/8" 1H9678 09012 Screw, steel (8 req'd) 1B2856 28982 Vent Screen, 1/4", Monel 0L0783 43062 Pusher Post Ca, S251 & S253, steel 1H9660 25062 Screw, S251 & S253, Steel 1A8990 28982 Vent Screen, 3/4", SST 1B6335 38392 Snap Ring, 3/4" vent only, SST T10669 24152 Spring Retainer, S252 & S254, steel T10073 24152 Pad, S251 & S253 T12461 T0012

* Recommended Spare Parts

FISHER CONTROLS COMPANY, INC. LIMITED ONE-YEAR WARRANTY 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.

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 if the product has been subjected to unreasonable use, negligence, accident in transit, alteration, improper

While this information is presented in good faith and believed to be accurate, Fisher Controls does not guarantee satisfactory results from reliance upon such information. Nothing contained herein is to be construed as a warranty or guarantee, express or implied, regarding the performance, merchantability, fitness

Fisher Controls Printed in USA

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.

or any other matter with respect to the products, nor as a recommendation to use any product or process in conflict with any patent. Fisher Controls reserves the right, without notice, to alter or improve the designs or specifications of the products described herein.

For information, contact Fisher Controls: Marshalltown, Iowa 50158 USA Cernay 68700 France

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