Singer Valve 106-RPS-D, 206-RPS-D Installation, Operating And Maintenance Instructions

SINGER MODEL 106/206-RPS-D

Differential Pressure Sustaining Valve

Schematic A0428B

DESCRIPTION:

Singer 106/206-RPS-D is a pilot operated differential
pressure sustaining valve, designed to open when the
pressure differential across the valve exceeds the set
point of Differential Sustaining Pilot (6).

DESCRIPTION OF OPERATION:

Main Valve (1) is normally open when pressure is
applied to the valve inlet. When the same pressure is
applied to the bonnet, the valve closes tight because the
area of the diaphragm is greater than the area of the
seat. Pressure above the diaphragm determines the
position of the Main Valve - whether it be open, closed
or in intermediate position.

Unless otherwise specified, the valve will be assembled
for service temperatures to 180oF (80oC).

Main Valve bonnet pressure is controlled with a pilot
circuit consisting mainly of Closing Speed Control (5)
and Differential Sustaining Pilot (6). Pilot (6) senses
the differential pressure between the inlet and the outlet
of Main Valve (1). When the differential pressure is
below the setpoint of Pilot (6), Pilot (6) is closed. The
upstream pressure is directed to the bonnet; Main Valve
(1) closes. When the differential pressure exceeds the
setpoint of Pilot (6), Pilot (6) opens and the Main Valve
opens.

INSTALLATION:

1.

See 106/206PG "Installation". Pressurize the valve
slowly and vent air as described in 106/206-PG
Instructions.

2. Model 106/206-RPS-D is normally factory
assembled to sense the pressures at the inlet and
the outlet of the Main Valve. Accuracy of control is
improved if the sensing is done remotely.

3. If the valve is to be used to limit flow through a
pump, low pressure sensing (1/8 NPT) of Pilot (6)
must be connected to pump suction.

ADJUSTING PROCEDURE:

1. SEE 'INSTALLATION' ABOVE.

2. Open isolating valves (2), (7) and (8).

3. Set Closing Speed Control (5) one to two turns
open, depending on valve size.

Installation, Operating and Maintenance Instructions

IOM A-0428B Page 1 of 1 July 2005

Surrey, BC. Canada. V3W 3H9

4. Install upstream and downstream pressure gauges.

5. Slowly open main inlet stop valve wide.

6. Note the pressure differential.

7. To change the differential pressure, loosen the Pilot
Adjusting Screw Locknut and turn the adjusting
screw on Pilot (6) clockwise to increase the
differential pressure, counterclockwise to decrease
it.

8. Lock adjusting screw in place when the desired
setting is complete.

9. Adjust Closing Speed Control (5):

• To close the Main Valve faster – Turn Closing Speed

Control (5) counterclockwise.

• To close the Main Valve slower – Turn Closing

Speed Control (5) clockwise. Do not close tight.

10. If the valve is equipped with optional Opening
Speed Control (9), adjust the opening speed as
required. If the valve is unstable at low flow,
increase the closing speed and decrease the
opening speed.

TROUBLESHOOTING AND MAINTENANCE:
Unstable operation: Bleed air from the Bonnet.

Connect sensing line to header. Install Opening Speed
Control.

Valve does not open: Pilot set too high. Isolating
Valve(s) closed. Opening Speed Control closed. Pilot
Diaphragm ruptured. Not enough pressure drop on the
Main Valve.

Valve does not close: Closing Speed Control (5)
closed. Strainer (3) plugged. Other obstruction in the
line from inlet to bonnet. Main Valve Diaphragm
ruptured. Obstruction in the Main Valve.

Maintenance: Clean Strainer. Frequency depends on
local conditions. Clean Main Valve and Pilot as required.
Lubricate the Body Seal in the Pilot. No other lubrication
is required. Check condition of Main Valve and Pilot
Diaphragms and other resilient parts. Replace when
required.

12850-87th Avenue

Ph: 604-594-5404

Fx: 604-594-8845

www.singervalve.com