Watson Smith SP2G2 Manostat Remote Manual and Auto/Manual Loading Stations

Remote manual and auto/manual pneumatic loading stations

The Watson Smith SP2G2 belongs to the Manostat loading station range: remote manual and auto/manual loading stations for controlling pneumatic systems with a Manostat regulator and different combinations of an air switching valve and pressure gauge. They give a visual display of the set pressure, precise regulation and excellent setting sensitivity, and the datasheet notes that Watson Smith pressure regulators are well suited to dead-end applications.

In the application drawing a controller or positioner with a 4 to 20 mA output feeds an actuator and valve, and the loading station lets the operator take manual control from a panel, with an auto signal switched in when needed. The unit uses an R27 regulator with the air switching valves and gauges. We found this datasheet only as a copy issued as Watson Smith Instrumentation literature (dated 04/07) and hosted by a UK instrument supplier; we did not find the product in current manufacturer literature, so treat it as an older, legacy line and confirm current availability, any replacement model and lead time before you rely on it.

Technical specifications

Model types

All stations come with a 3 mm black-painted mounting plate with corner fixing straps. The SP is a Manostat regulator plus a 63 mm diameter gauge with a phosphor bronze Bourdon tube to BS 1780, for horizontal or vertical mounting. The SP2 adds a rotary two-position, three-way auto/manual valve, and its gauge shows the manual set pressure only. The SP2G2 adds a second gauge to measure the auto signal pressure before switching, and the SP2G2W is the weatherproof version for surface or post mounting with a yoke for a 50 mm (2 inch) post.

Part numbers printed include 359000R (SP2H, 0.2 to 1 bar, 0 to 100 percent), 371201R (SP2G2H, 0.2 to 1 bar, captured bleed), 379000R (SP2G2H, 0.2 to 1 bar), 382100R (SP2G2V), 391200R (SP2G2W, 0 to 30 psi), 392100R (SP2G2W, 0.2 to 1 bar), 393200R (SP2G2W, 0 to 2 bar), 399100R (SP2G2W, 3 to 15 psi, 0 to 100 percent) and 399110R (SP2G2, 3 to 15 psi, 0 to 100 percent). Options to special order are special scales, other pneumatic connections, other materials, feedback on switches and explosion-proof switches.

Selection notes

Choose between a manual-only station and an auto/manual station by whether the loop needs a controller signal switched in. Then select the output range and gauge scale, the mounting (panel or weatherproof post), the connection style (1/4 NPT or 6 mm OD tube as drawn). A small pressure of under 2 psig will always show at the bottom of the gauge scale because of regulator servo operation, so do not treat it as a leak. Confirm availability, since only a 2007 datasheet was located.

How the Watson Smith SP2G2 works

The Manostat regulator sets an air pressure to the actuator. The operator turns the knob to set the pressure. The two gauges show the supply and the output. The switching valve selects manual or auto control.

Where the SP2G2 is used

• Manual control of pneumatic valves
• Panel-mounted loading stations
• Auto and manual switching of positioners
• Pneumatic actuator control
• Dead-end air applications

Selection checklist for the SP2G2

• Model variant
• Output pressure range
• Number of gauges
• Weatherproof need
• Air supply pressure
• Flow demand
• Connection size
• Panel or wall mounting

Installation, commissioning and maintenance notes for the SP2G2

Fit the station on the plate with the corner straps. Connect clean, dry air to the supply port. Connect the output to the actuator or the positioner. Set the pressure with the knob and read the gauge. Drain the filter and check the diaphragms at regular intervals.

Requesting a quotation for the Watson Smith SP2G2

Please send the model, the pressure range and the connections. Seven Star LLC serves industrial customers in Oman and the GCC and replies with a quotation based on the information provided.

SP2G2 station type

It is a manual and auto/manual loading station.

SP2G2 range

It belongs to the Manostat loading station range.

SP2G2 regulator

It uses an R27 regulator.

SP2G2 gauges

It has two gauges.

SP2G2 gauge size

The gauges are 63 mm in diameter.

SP2G2 gauge element

The gauge uses a phosphor bronze Bourdon tube.

SP2G2 related models

The related models are SP, SP2 and SP2G2W.

SP2G2 weatherproof model

The SP2G2W is the weatherproof version.

SP2G2 air supply

The supply is oil-free dry air or dry gas.

SP2G2 maximum supply pressure

The maximum supply is 10 bar or 150 psig.

SP2G2 flow capacity

The flow is up to 300 Nl/min.

SP2G2 pressure ranges

The ranges are 2 to 25, 2 to 60 and 2 to 120 psi.

SP2G2 response time

The response time is below 0.2 seconds.

SP2G2 sensitivity

The sensitivity is better than 0.3 mbar.

SP2G2 temperature range

The range is minus 20 to plus 70 degrees C.

SP2G2 protection

The protection rating is IP65.

SP2G2 connections

The ports are 1/4 NPT female.

SP2G2 body material

The body is epoxy-painted zinc die-cast.

SP2G2 diaphragms

The diaphragms are nitrile.

SP2G2 mounting plate

The plate is 3 mm and black-painted.

Station records for the SP2G2

Record the set pressure, the loop number and the service dates.

Choosing the right SP2G2 variant

Choose the variant from the control mode and the site.

Documents and quotation

The datasheet is attached for download. Seven Star LLC is an independent supplier in Muscat. Send the model or order code, quantity and operating conditions and we will request a quotation; availability depends on the model. Related items: Regulators.