Fisher 92C Instruction Manual

Instruction Manual D100255X012

January 2020

Type 92C Steam Regulator

WARNING

Fisher™ regulators must be installed, operated and maintained in accordance with federal, state and local codes, rules and regulations and Emerson Process Management Regulator Technologies, Inc. instructions.

Installation, operation and maintenance

procedures performed by unqualied

personnel may result in improper adjustment and unsafe operation. Either condition may result in equipment damage

or personal injury. Use qualied personnel

when installing, operating and maintaining the Type 92C regulator.

Introduction

Scope of the Manual

This instruction manual provides installation, maintenance and parts ordering information for the Type 92C steam self-powered control valve and the Type 6392 pilot. Both the pilot-operated and the pressure-loaded constructions are covered. The Type 92C is also available with a Type 6492HM or 6492HTM safety override pilot. The pressure-loading device and accessories used with this valve are covered in other manuals.

regulator or 670 Series panel-mounted regulator may be used as the loading regulator.

A Type 6492HM (or 6492HTM) safety override pilot is also available for the Type 92C. The Type 6392 pilot is used in a series installation with the Type 6492HM (or 6492HTM) safety override pilot installed on the upstream valve. The Type 6492HM (or 6492HTM) safety override pilot senses pressure downstream of the second valve, and prevents pressure from rising above safe operating pressure in the event the downstream valve fails. This system is approved by ASME B31.1-1989, 122.14.2.A, and can replace an ASME safety valve when vent piping is not practical and upstream pressure does not exceed 400 psig / 27.6 bar. Local codes and standards may require approval by an appropriate authority prior to installation.

Type 92C

W3111_2

Figure 1. Type 92C Pilot-Operated Regulator

WARNING

Description

The Type 92C steam regulator is a gray cast iron, steel or stainless steel pressure-reducing regulator for steam or hot air service. This regulator is available with a Type 6392 pilot for use as a pilot-operated regulator (Figure 1) or without a pilot for use as a pressureloaded regulator. The pilot-operated version uses inlet pressure as the operating medium; no separate air supply is required. The pressure-loaded version is used where remote adjustment of the regulator pressure setting is required; a 67 or 1301 Series

The Type 92C safety override system

does not provide positive shuto󰀨 in

dead end service. It is intended for large distribution systems where steam leakage will condense before steam pressure builds up. Downstream piping and components must be rated for maximum upstream steam pressure for dead end service. Failure to do so could cause personal injury or death.

Type 92C

Specications

This section lists the specications for Type 92C regulator. Additional specications for an individual regulator are

found on the regulator body and pilot nameplates.

Body Sizes and End Connection Styles

SIZE

NPS 1/2, 3/4 or 1 /

DN 15, 20 or 25

Gray Cast Iron Steel or CF8M Stainless Steel

NPT

BODY MATERIAL

NPT, CL150 RF, CL300 RF

or PN 16/25/40

Orice Sizes

NPS 1/2 / DN 15 Main Valve:

9/16 in. / 14 mm NPS 3/4 and 1 / DN 20 and 25 Main Valves:

3/4 in. / 19 mm is standard; 9/16 in. / 14 mm is optional

Maximum Allowable Inlet and Pilot Supply Pressures

(1)

Gray Cast Iron Construction: 250 psig / 17.2 bar Steel and Stainless Steel Construction:

300 psig / 20.7 bar

Regulator Pressure Drops

(1)

Minimum: 15 psi / 1.0 bar Maximum Operating: 150 psi / 10.3 bar for

outlet pressure settings equal to or below 50 psig / 3.4 bar; 200 psi / 13.8 bar for outlet pressure settings above 50 psig / 3.5 bar

Maximum Emergency

Gray Cast Iron construction: 250 psi / 17.2 bar Steel and Stainless Steel construction:

Maximum Material Temperature Capabilities

Gray Cast Iron Construction: 406°F / 208°C Steel and Stainless Steel Construction:

500°F / 260°C

Optional High-Temperature Steel or

Stainless Steel Body: 650°F / 343°C

Pressure Registration

With Pilot: External Without Pilot: Internal

Downstream Control Line Connection

1/4 NPT (internal) in pilot body (downstream control line not required for pressureloaded regulator)

300 psi / 20.7 bar

Loading Pressure Connection

Outlet Control Ranges

See Table 1

Maximum Outlet Pressures

(1)

Maximum Operating Outlet Pressure:

150 psig / 10.3 bar

Maximum Emergency Outlet (Casing) Pressure

Gray Cast Iron construction: 250 psig / 17.2 bar Steel and Stainless Steel construction:

300 psig / 20.7 bar

Loading Pressure for Pressure-Loaded Regulator

(1)

1/4 NPT (internal) in main valve diaphragm ange

(this connection is factory-piped to the pilot on pilot-operated regulator)

Pilot Spring Case Vent

3/32 in. / 2.4 mm drilled hole

Approximate Weights

Gray Cast Iron, Steel or Stainless Steel Body with Pilot: 20 lbs / 9.1 kg

Gray Cast Iron, Steel or Stainless Steel Body without Pilot: 16 lbs / 7.3 kg

See Figure 2 to determine loading pressure. Maximum allowable loading pressure is 250 psig /

17.2 bar for gray cast iron construction and 300 psig / 20.7 bar for steel or stainless steel construction; the maximum allowable diaphragm

di󰀨erential pressure of 150 psi / 10.3 bar

for gray cast iron, steel and stainless steel constructions must not be exceeded.

1. Pressure/temperature limits in this Instruction Manual and any applicable code limitations must not be exceeded.

(1)

TYPE 92C REGULATOR

PILOT LOADING LINE

Type 92C

26A3808-A A2508-1

PRESSURE DROP ACROSS VALVE (bar)

2 4 6 8 10 12

DIAPHRAGM DIFFERENTIAL (psi)

PRESSURE DROP ACROSS VALVE (psi)

3/4 in. / 19 mm

orice size

9/16 in. / 14 mm

orice size

50 100 150 200

Figure 2. Diaphragm Dierential Pressure

for Pressure-Loaded Regulator

TYPE

6492HM

6492HTM

SPRING RANGE

psig bar

10 to 30 0.69 to 2.1 Yellow 5 psig / 0.34 bar over normal distribution pressure

25 to 75 1.7 to 5.2 Green

70 to 150 4.8 to 10.3 Red

80 to 250

15 to 100 1.0 to 6.9

PILOT SUPPLY

TYPE 6392 PILOT

0.5

DIAPHRAGM DIFFERENTIAL (bar)

TOP VIEW OF REGULATOR AND

PILOT CONNECTIONS

STRAINER

16A1548-B A2522-1

Figure 3. Typical Pilot-Operated Type 92C

Regulator Installation

Table 1. Safety Pilot Outlet (Control) Pressure Ranges

MINIMUM PRESSURE AT WHICH MONITORING

10 psig / 0.69 bar over normal distribution pressure

5.4 to 17.2

SPRING COLOR

Unpainted

DOWNSTREAM CONTROL LINE

BYPASS LINE

PILOT CAN BE SET

TYPE 6392 PILOT

DOWNSTREAM CONTROL LINE

TYPE 92C REGULATOR

Table 2. Outlet Pressure Ranges

SPRING USAGE

Standard use up to

500°F / 260°C

High-pressure and/or High

temperature over 500°F / 250°C

OUTLET PRESSURE RANGE

psig bar In. mm In. mm

5 to 70 0.34 to 4.8 1E392627012, Green 0.170 4.32 2.00 50.8

20 to 150 1.4 to 10.3 1E392727142, Red 0.207 5.26 1.94 49.0

15 to 100 1.0 to 6.9 14B9941X012, Unpainted 0.192 4.88

80 to 200 5.5 to 17.2 14B9940X012, Unpainted 0.282 7.16

SPRING PART NUMBER

AND COLOR

Table 3. Flow Coecients

ORIFICE SIZE WIDE-OPEN FOR RELIEF SIZING

In. mm C

9/16 14 170 8.5 5

3/4 19 240 12 7.1

1. Cv = Cs x 20 ÷ C

SPRING WIRE DIAMETER SPRING FREE LENGTH

(1)

34 0.67

Table 4. IEC Sizing Coecients

BODY SIZE

NPS DN X

1/2 15

3/4 or 1 20 or 25 0.44 0.73 0.38 0.82

0.73

9/16 in. / 14 mm 3/4 in. / 19 mm

0.38

ORIFICE SIZE

0.82

- - - - - - - - - - - -

1.96 49.8

Type 92C

TYPE 92C MAIN VALVE

TYPE 6492HM SAFETY

OVERRIDE PILOT

TYPE 6492HM SAFETY

OVERRIDE PILOT

TYPE 92C MAIN VALVE

TYPE 6392 PILOT

TOP VIEW

TYPE 6392 PILOT

TYPE 92C MAIN VALVE TYPE 92C MAIN VALVE

E0656

E0657

TYPE 6492HM SAFETY

GAUGE

BLOCK VALVE

OVERRIDE PILOT

TYPE 6392 PILOT

TYPE 92C MAIN VALVE TYPE 92C MAIN VALVE

SIDE VIEW

GAUGE

TYPICAL TYPE 92C WITH TYPE 6492HM OR 6492HTM SAFETY OVERRIDE PILOT INSTALLATION

TYPE 6392 PILOT

GAUGE

BLOCK VALVE

Figure 3. Typical Pilot-Operated Type 92C Regulator Installations (continued)

Type 92C

Note

To determine required loading pressure,

add the diaphragm di󰀨erential pressure

to the desired outlet pressure setting.

Principle of Operation

Pilot-Operated Regulator

Refer to Figure 5. Pilot supply pressure is piped from the inlet side of the main valve to the pilot inlet connection. Downstream pressure registers under the main valve diaphragm through the pitot tube and under the pilot diaphragm through the downstream control line.

When downstream pressure decreases to a value below the setting of the pilot regulator spring, the pilot spring forces the pilot valve plug open, increasing the loading pressure on the top of the main valve diaphragm. The increased loading pressure on top of the main valve diaphragm and decreased downstream pressure under the main valve diaphragm force the main valve diaphragm and stem downward. This

opens the main valve plug, and increases ow to

the downstream system, thus restoring downstream pressure to the setting of the pilot regulator spring.

When downstream pressure increases it registers under the pilot diaphragm and overcomes the force of the pilot spring. This allows the pilot valve spring to close the pilot valve plug and causes excess loading pressure to bleed to the downstream system through the pilot bleed hole. At the same time, increased downstream pressure registers under the main valve diaphragm. The decreased loading pressure on top of the main valve diaphragm and increased downstream pressure under the main valve diaphragm force the main valve diaphragm upward. This allows the main valve plug spring to close the main valve plug,

reducing ow to the downstream system.

Pressure-Loaded Regulator

Refer to Figure 7. With a pressure-loaded regulator, a remote, adjustable loading regulator provides loading pressure to the top of the main valve diaphragm. Downstream pressure registers under the main valve diaphragm through the pitot tube.

When downstream pressure decreases, it registers under the diaphragm and allows the stem and plug to move downward, thereby opening the valve to increase downstream pressure.

When downstream pressure increases, it registers under the diaphragm and forces the stem and plug to move upward. The upward force of the spring

causes the valve to close, which decreases ow to

the downstream system thus decreasing downstream pressure. In hot air service, supply air above the diaphragm becomes compressed and is vented to the atmosphere. If a steam supply is used, the steam is vented downstream.

Safety Override Pilot Principle of Operation

Refer to Figure 6. Once placed in operation, the upstream Type 6392 pilot senses the intermediate pressure between both valves, and the Type 6492HM (or 6492HTM) pilot senses downstream pressure

of the second valve. As demand for ow increases,

intermediate pressure will fall causing the Type 6392 pilot to open. As the Type 6392 pilot valve opens, loading pressure to the main valve increases, opening the main valve.

The Type 6492HM (or 6492HTM) safety override pilot remains open because its setpoint is above the setpoint of the downstream valve. In the unlikely event that the downstream valve fails open, downstream pressure will rise above the downstream valve’s setpoint. This pressure is sensed by the Type 6492HM (or 6492HTM) safety override pilot. As downstream pressure increases the safety override pilot closes, reducing loading pressure to the main valve, which positions the main valve to maintain downstream

pressure as specied per ASME Boiler and Pressure

Vessel Code, section VIII.

In the event that the upstream valve fails, the downstream regulator will prevent downstream pressure from rising above safe operating levels.

It is recommended to install some type of warning system, such as a sentinel relief valve, to warn the operator that a valve has failed in the system. This will prevent prolonged operation with one valve, which could cause valve trim wear and noise associated with

operation at high di󰀨erential pressures.

When operating in most steam systems, valve setpoints should be in strict accordance to ASME Boiler and Pressure Vessel Code, section VIII. The Type 6492HM (or 6492HTM) safety override pilot should be set at 10 psig / 0.69 bar or 10% above maximum downstream operating pressure of the second valve, whichever pressure is greater. For example, most HVAC systems operate at 15 psig /

1.0 bar, so the safety override pilot should be set no higher than 25 psig / 1.7 bar.

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