USER GUIDE
7
PCS 4000
SINGLE WELL CONTROLLER
How pressure operation works
When set to a pressure operating mode, the controller
opens the A-valve based on the difference between 2
pressure values. The pressure values used are:
Mode 1: Time only input (no pressure)
Mode 2: Tubing pressure minus sales line pressure
Mode 3: Casing pressure minus tubing pressure
Mode 4: Casing pressure minus sales line pressure
Note:
When set to Mode 1 or time mode, the controller
opens and closes the A-valve and B-valve based on time
input. It does not respond to pressure input or flow rate
input.
Here are the steps in the pressure operation cycle.
1 The controller closes the A-valve and counts down the
FALL TIME (SET 05). This gives the plunger time to fall
to the bottom of the well. The status display shows
CLOSE 0:00:00.
Note:
CLOSE TIME is normally set to 00:00:00 because
the controller opens the A-valve in response to
changes in pressure.
2 While the A-valve is closed, the casing pressure and
tubing pressure rise.
3 The controller monitors:
Tubing pressure minus line pressure differential in
Mode 2
Casing pressure minus tubing pressure differential
in Mode 3
Casing pressure minus line pressure differential in
Mode 4
The controller opens the A-valve when:
The difference between the 2 pressures is equal
to or greater than the DIFFERENTIAL OPEN
PRESSURE (SET 12) value (see “DIFFERENTIAL
OPEN PRESSURE” on page 9),
and
The FALL TIME countdown reaches zero.
If the DIFFERENTIAL OPEN PRESSURE value is
reached during the FALL TIME countdown, the status
display shows the FALL TIME remaining.
Note:
You can use any “open” function together with or
in place of DIFFERENTIAL OPEN PRESSURE. After the
FALL TIME countdown has reached zero, the controller
opens the A-valve as soon as it receives input from any
“open” function. For more information, see “Features
for Opening the A-Valve” on page 11.
4 The controller opens the A-valve and counts down the
OPEN TIME (SET ON).
If the plunger arrives during the OPEN TIME
countdown, the controller goes to step 6.
If the plunger does not arrive during the OPEN TIME
countdown, the controller goes to step 5.
5 The controller opens the optional B-valve and counts
down the B OPEN TIME (SET B ON).
If the plunger arrives during the B OPEN TIME
countdown, the controller goes to step 6.
If the plunger does not arrive during OPEN TIME or
B OPEN TIME, the controller closes the A-valve and
B-valve and counts down the MANDATORY SHUT-
IN TIME (SET 03). When this countdown reaches
zero, the controller goes to step 4.
Note:
If the well has liquid trailing behind the plunger,
you may want to set B DELAY TIME. See “B DELAY
TIME” on page 13 for more information.
6 The controller counts down the DELAY TIME (SALES)
(SET 02) while monitoring the casing pressure, flow
rate, or both.
Note:
DELAY TIME (SALES) is the maximum time the
well is allowed to stay open after the plunger arrives.
The controller responds to the first input to close the
well. The close input may be:
Casing pressure – see
DELAY TIME (SALES) countdown reaches zero –
see page 13.
Another close input unrelated to casing pressure,
low flow rate, critical flow K factor, or time. For
example: low or high sales line pressure, a manual
input to close the well, and so on.
7 Casing pressure normally drops while the plunger
rises. When the casing pressure starts to build, the
controller monitors the increase in pressure. When
the increase equals the DIFFERENTIAL CLOSE
PRESSURE (DIP) value, the controller goes to step 8.
Usually, a minimal increase in pressure, such as 1 or 2
psi, is desirable.
8 The controller counts down the DELAY CLOSE TIME
(SET 08). When the DELAY CLOSE TIME countdown
reaches zero, the controller checks the casing
pressure again to see if it has still increased by the
DIFFERENTIAL CLOSE PRESSURE (DIP) value.
If the increase is a brief spike in pressure, the
controller continues the DELAY TIME (SALES)
countdown. The controller goes back to step 7.
If the increase is an actual or solid pressure
increase, the controller goes back to step 1.
