Service instructions, Potentiometers – Bell & Gossett V57050B SRS Pneumatic Purge Valve User Manual

Page 3

POTENTIOMETERS

As indicated in Figure 5, there are 8 ranges to choose from.
The potentiometers below the DIP switches are used to adjust
the settings within the desired range. DIP switches 1-3 are
used to adjust the duration. DIP switches 6-8 are used to
adjust the cycle. Note that setting of time is proportional, e.g.
8 sec in the .5 s - 10 s range becomes 8 h when changed to
the .5 - 10 h range. Adjustment is as follows:

1. Disconnect or otherwise interrupt power to the timer before

programming the unit.

2. Remove cover of timer (using a screw driver to remove the

screw in the center of the cover).

3. Calculate the percentage of the cycle range required.

4. Change the DIP settings 1-3 and/or 6-8 to a lower range.

5. Adjust potentiometers as labeled in Figure 5 to fine-tune to

desired setting:

Counter clock-wise (CCW) = decrease
(t

min

is maximum CCW setting)

Clock-wise (CW) = increase
(t

max

is maximum CW setting)

6. Connect the power to the timer and observe the results.

Determine if additional adjustment of the potentiometer is
necessary. If additional adjustment is required then discon-
nect or interrupt power to the timer and repeat from Step 4,
if not proceed to Step 7.

7. Return DIP settings to desired range.

8. Replace cover on the timer.

9. Supply power to the timer.

EXAMPLE

An example will help illustrate the procedure:

Desired setting: Cycle every 8 hours with 20 sec purge dura-
tion per cycle.

Current factory setting: Cycle every 4 hours with 10 sec purge
duration per cycle.

Step 1: Disconnect or interrupt the power to the timer.

Step 2: Remove the cover to the timer by removing the screw
on the face of the coverplate.

Step 3: 8 hours is 8/10 of the present range.

Step 4: Since settings are proportional, adjustment can be
made in shorter time ranges to enable observation of the
results of the changes in a shorter period of time. Adjust the
cycle time by setting the DIP switches to the .5 s - 10 s range
(6-8 are all set down). Now the valve will cycle every 4 sec-
onds (instead of 4 hours).

Step 5: Adjust the potentiometer located below the 6-8 DIP
switches CW to increase the cycle time to the desired 8 sec-
onds. Turn on the power briefly to confirm that the desired
setting is attained, then disconnect or interrupt the power
before further adjustments are made or before proceeding.
Once complete, set the DIP switches to a range which will
facilitate the setting of the purge duration. In our example, 20
sec falls within the 1.5 s - 30 s range. Since t

max

and t

min

are

obtained by potentiometer adjustment fully CW and CCW
respectively, adjust the potentiometer under DIP settings 1-3
to a setting between these two values. Turn on the power
briefly to confirm that the desired setting is attained, then dis-
connect or interrupt the power before further adjustments are
made or before proceeding.

Step 6: Return the cycle time setting to the .5 h - 10 h range
by adjusting the DIP settings 6-8 all up, and the purge setting
to the 1.5 s - 30 s range by adjusting DIP settings 1-3 down,
down and up respectively.

Step 7: Replace cover to the timer.

Step 8: Turn on the power to the timer.

SERVICE INSTRUCTIONS

These valves are designed for sediment service. It is possible,
particularly in abrasive service, that sediment may become
lodged in valve seat upon valve closure which results in leak-
ing. If the valve is leaking, manually purge the valve by depress-
ing the button on the side of the solenoid valve until the water
appears relatively clear. See Figure 4.

Then release your finger from the button to stop the purge. If
leaking continues, this may be a sign that the valve seat is
damaged and in need of replacement. The following is a pro-
cedure to replace the diaphragm. Other parts in need of
replacement or repair shall be done at the factory.

ton

toff

min

max

.5 s

10 s

down

down down

down

down down

1.5 s

30 s

down

5 s

100 s

down

down down

down

.5 min

10 min

down

1.5 min

30 min

down

down down

5 min

100 min

down

12 min

240 min

down down

down

.5 h

10 h

down

DANGER: ELECTRICAL SHOCK HAZARD:
Disconnect or otherwise interrupt power to the timer

before programming the unit. Failure to follow these instruc-
tions will result in serious personal injury or death.

CAUTION: Changing the #4 and #5 setting can result
in excessive water loss. Do not change these settings.

Failure to follow this instruction can result in property damage.

Figure 5

decrease

purge

decrease

cycle

increase
purge

increase
cycle