Armstrong OB-2000PT is a high-performance, diaphragm-operated externally piloted pressure and temperature combination regulator. It is designed for large capacity applications such as heat exchangers, steam coils, steam dryers, plating tanks, and parts washers.

It is used in applications where maximum pressure should be limited and the temperature of the heated medium is controlled using a single seated main valve. The temperature pilot and capillary unit can be easily disconnected, making repairs or temperature range changes quick and easy. It is available in sizes 1/2" through 6" and with a choice of four spring ranges, six temperature ranges, and three capillary lengths.

Specifications

Application	Inlet Pressure psig (bar)	Minimum Differ. Pressure psig (bar)	Reduced Pressure & Spring Color psig (bar)	Temperature Ranges °F (°C)	Temperature Accuracy °F (°C)	Capillary Lengths feet (meters)
Steam	NPT: 15 - 300 (1 - 20) 150 lb Flanged: 15 - 185 (1 - 13) 300 lb Flanged: 15 - 300 (1 - 20)	7 (.48)	1.5 - 3 (.10 - .21) Yellow 3 - 21 (.21 - 1.4) Yellow 15 - 200 (1.0 - 13.8) Green	18 - 59 (-8 - 15) 50 - 97 (10 - 36) 86 - 144 (30 - 62) 131 - 201 (55 - 94) 176 - 260 (80 - 127) 239 - 361 (115 - 183)	±2 (±1) From Set Point	6-1/2 (2)* 9-1/2 (3) 16-1/2 (5)

*Standard length.

Sensor and Accessory Specifications

Capillary Material	Capillary Temperature Ranges °F (°C)	Bulb Material	Bulb Connection	Thermal Well Material	Thermal Well Connection
Copper Capillary Tube With 304 Stainless Steel Armor Shield	18 - 59 (-8 - 15) 50 - 97 (10 - 36) 86 - 144 (30 - 62) 131 - 201 (55 - 94) 176 - 260 (80 - 127) 239 - 361 (115 - 183)	Nickel Plated Copper Bulb	3/4" (20 mm) NPT	Brass* 304 Stainless Steel*	1" (25 mm) NPT

*Standard. Other material available upon request.

WARNING

Capillary can withstand a maximum of 36°F (20°C) above rated range. If desired set temperature is in temperature range overlap, select lower range.

Materials

Component	Body Material	Valve & Seat Material	Maximum Temperature °F (°C)
Main Valve	Ductile Iron ASTM A536	Stainless Steel AISI 420	450 (232)
Temperature Pilot Valve	Bronze ASTM B584	Stainless Steel AISI 420	450 (232)
Pressure Pilot	Ductile Iron ASTM A536	Stainless Steel AISI 420	450 (232)

Dimensions and Weights

Size in (mm)	Face-to-Face NPT in (mm)	Face-to-Face 150# in (mm)	Face-to-Face 300# in (mm)	H in (mm)	H1 in (mm)	A in (mm)	G in (mm)	Weight NPT lb (kg)	Weight 150# lb (kg)	Weight 300# lb (kg)	Cv
1/2 (15)	5-15/16 (150)	5-9/16 (141)	5-3/4 (147)	15-3/4 (398)	6-3/4 (170)	7-15/16 (200)	6-1/2 (166)	47 (22)	49 (23)	55 (25)	5.0
3/4 (20)	5-15/16 (150)	5-1/2 (140)	5-3/4 (147)	15-3/4 (398)	6-3/4 (170)	7-15/16 (200)	6-1/2 (166)	47 (22)	49 (23)	55 (25)	7.2
1 (25)	6-15/16 (160)	5-3/4 (147)	6-1/4 (159)	15-15/16 (404)	6-15/16 (175)	8-15/16 (226)	7 (178)	57 (26)	59 (28)	64 (29)	10.9
1-1/4 (32)	7-1/8 (180)	6-1/2 (166)	7-1/16 (179)	17-1/8 (434)	7-5/8 (192)	8-15/16 (226)	7-1/4 (185)	67 (31)	69 (31)	74 (34)	14.3
1-1/2 (40)	7-1/8 (180)	7-7/16 (189)	7-15/16 (202)	17-1/8 (434)	7-5/8 (192)	8-15/16 (226)	7-1/4 (185)	67 (31)	69 (31)	75 (34)	18.8
2 (50)	9-1/8 (230)	8-9/16 (217)	9-1/8 (232)	19-5/8 (498)	8-1/2 (216)	10-15/16 (276)	6-1/2 (166)	89 (41)	94 (43)	100 (46)	32
2-1/2 (65)	-	10-15/16 (278)	11-1/2 (292)	21-3/4 (552)	9-13/16 (251)	13-13/16 (352)	6-1/2 (166)	-	158 (72)	167 (76)	60
3 (80)	-	11-3/4 (298)	12-7/16 (315)	22-5/8 (575)	10-7/16 (264)	13-13/16 (352)	6-1/2 (166)	-	171 (78)	183 (83)	78
4 (100)	-	13-1/2 (343)	14-1/8 (359)	25-15/16 (658)	12-5/8 (321)	15-13/16 (401)	6-1/2 (166)	-	263 (120)	281 (128)	120

Note: For 6” (150 mm) consult factory.

Installation Instructions

Points to Remember When Installing

• Drain condensate at inlet of pressure/temperature regulator with inverted bucket steam trap.
• Protect temperature regulating valve from dirt and scale by installing strainer with 100 mesh screen at inlet of valve.
• Install shutoff valves on either side of the regulating valve along with a by-pass line for maintenance purposes.
• Install vacuum breaker after the outlet of equipment and before the steam trap.
• Install sensor so it is fully immersed in the fluid being heated.
• If temperature well is used, apply heat transfer medium to sensor before insertion into well.
• Place thermometer into system in close proximity to temperature sensor for accurate valve adjustment.
• If possible, do not elevate condensate after steam trap.
• Determine pressure setting before temperature setting (OB-2000PT only).

Assembly & Installation

The pressure/temperature regulator will come in two (2) boxes. One box will contain an integral mount (pressure pilot mounted on the top of the main valve) main valve and the second box containing the temperature pilot with fittings which is not connected to the integral mounted valve and the capillary system.

A. Assembly

1. Do not lose the bellows follower (10), union gasket (45) and pre-formed copper D pipe (46).
2. Insert copper union gasket (45) into union fitting, tighten the union joint and install pre-formed copper D (46) pipe.

B. Installation of OB-2000PT Main Valve

1. Align flow direction with direction of arrow cast into body.
2. Install OB-2000PT perpendicular to horizontal piping so that the diaphragm chamber is located at the bottom.

C. Installation of Capillary System

1. Once the valve body is installed, insert bellows follower (10), which was packaged with the capillary system inside the sensor bellows (35) with the flat side down toward the capillary bellows. Turn the adjusting screw (15) counter clockwise to relieve spring tension. Attach capillary system to temperature pilot valve body and tighten capillary ring union (22).
2. Thermal Bulb (23) may be installed in any position. However, care should be taken so that at least three quarters of the thermal bulb is touching the fluid being heated.
3. Screw in bushing (24) first and attach thermal bulb (23) with packing nut (36).

4. Do not twist or bend capillary sharply. Bending radius of capillary should not be more than 1-1/2". Position capillary so that it does not touch steam lines, hot water lines, or regulator.
5. Install a thermometer into the fluid close to the thermal bulb.
6. When using the thermal bulb (23) in a pipe, make sure the thermal bulb is installed in a location where the fluid freely flows around the bulb.
7. If a thermal well is used. Make sure heat transfer compound is applied to the thermal bulb before installation into the well.

Regulating Method

INFO

Temperature control is best achieved when the delivery pressure is the lowest steam pressure capable of maintaining the desired temperature at maximum load.

1. Open valve on drip leg to allow inverted bucket steam trap to drain condensate on OB-2000PT inlet.
2. Close inlet and outlet valves to OB-2000PT and open bypass line to clean the system. Be sure to close bypass line after cleaning the system. During blow down, make sure that the temperature does not rise higher than the limit of the capillary unit, otherwise damage to capillary may occur.
3. Loosen lock nut (16) on the temperature pilot and turn the adjusting screw (15) and align the needle with the required temperature position on the dial. Note that the number on the dial will give an approximate temperature value with the corresponding temperature range.
4. Loosen lock nut (28) on the pressure pilot and turn adjusting screw (27) counterclockwise removing all tension from adjusting spring (24).
5. Open valve on outlet of OB-2000PT and also on control pipe.
6. Open inlet valve to OB-2000PT – SLOWLY.
7. Turn the adjusting screw (27) on pressure pilot valve clockwise until the heater output is 5°F above the desired temperature setting. If temperature adjustment in step 3 limits this operation, adjust temperature pilot adjusting screw accordingly. Make sure all valves between the OB-2000PT and equipment are open and equipment is calling for steam.
8. Turn adjusting screw (15) on temperature pilot counterclockwise, lowering to the desired temperature.
9. Allow system to stabilize and adjust temperature accordingly.
10. Tighten lock nut (16) on the temperature pilot and lock nut (28) on pressure pilot.
11. If adjustments are made at partial load the temperature will sag under heavier loads. When maximum load occurs increase pressure setting enough to maintain desired temperature.

Disassembly

DANGER

Equipment under pressure - Operating temperature > 100°C. Make sure temperature regulator is cold and pressure has been relieved before handling!

A. Disassembly of Temperature Pilot Valve

1. Loosen capillary ring union (22) and temperature sensor bellows (35). Make sure not to lose bellows follower (10).
2. Loosen lock nut (16) and turn adjusting screw (15) counter clockwise (left), freeing up adjusting spring (14).
3. Remove four hexagonal bolts (17) from the spring housing (2) and remove adjusting spring (14).
4. Remove top bellows plate (6) and top seal bellows (5).
5. Loosen the guide (7) and remove the bottom bellows plate (8) and the bottom bellows seal (5) from the bottom half of temperature pilot.
6. Remove pilot valve and stem (3).
7. For assembly procedure, follow reverse order.

B. Disassembly of Pressure Pilot Valve

1. Loosen the lock nut (28) and the adjusting screw (27) counterclockwise (left) and turn until the pressure is relieved from set point adjusting spring (24).
2. Remove four hex head bolts and take out adjusting spring (24), bottom spring plate (26), top spring plate (25), and two pilot diaphragms (23).
3. Remove pilot valve assembly (17, 18, 19, 20, 21) at the center of the pilot body (2).
4. Pilot body can be removed from main valve by disconnecting fitting (30A) and removing four hex bolts (38). Care should be taken when removing pilot from main valve. The main valve is held by a spring which is compressed.

C. Disassembly of Main Valve

1. Disconnect the copper tubing on the side of the valve.
2. Remove the four hex head bolts (38) from the pilot body (2) to remove the pressure pilot from the main valve body (1). Care should be taken when doing this procedure. The main valve is held by a spring (13) which is compressed. Once bodies are apart, remove spring plate (14), screen (15), main valve spring (13) and main valve (6).
3. Use a T-Bar wrench to remove valve seat (7).
4. Remove all nuts and bolts (41) from diaphragm case separating the top diaphragm case (4) and the bottom diaphragm case (5), main diaphragms (12), retainer (11) and main spindle (9).

Troubleshooting Guide

Problem	Cause	Solution
Temperature Regulator does not reach desired set temperature.	Improper adjustment.	Re-adjust according to Regulating Methods.
	Faulty steam trap draining equipment.	Check trap and correct problem.
	Inadequate pressure to eliminate condensate.	Re-pipe system.
	Bellows follower (10) was not installed.	Install bellows follower.
	No transfer medium applied to sensor.	Apply heat transfer paste to thermal bulb before installing in well.
	Incorrect capillary range.	Check label and change to correct range.
Temperature rises excessively.	Improper adjustment.	Re-adjust according to Regulating Methods.
	Dirt or scale on main valve (6) and main valve seat (7) or flawed valve and seat.	Disassemble and clean valve and seat. In case of flawed valve and seat replace them.
	Dirt or scale on pilot valve and stem (3), pilot valve seat (4).	Disassemble pilot and clean.
	Fitting orifice (30B) is blocked.	Remove and clean.
	Broken capillary system.	Replace capillary system.
	By-pass line leaks.	Repair by-pass line.
Large variation between thermometer and temperature regulator setting.	Thermal bulb or thermometer are installed in wrong location.	Relocate the thermal bulb so the fluid freely flows around 3/4" of the bulb and/or relocate the thermometer closer to the thermal bulb.
	Inlet pressure too high.	Lower inlet pressure. On low load applications, the lower the inlet pressure, the more stable the control will be.
	Dirt or scale on pilot valve and stem (3), guide (7) and pilot valve seat (4), main spindle (9) is dirty.	Disassemble and clean.
	Body gasket leaks.	Tighten bolts and replace gaskets
External leak.	Broken top bellows seal (5).	Replace top bellows seal.