Hanna Instruments BL Series Pumps User Manual

Page 12

TROUBLESHOOTING GUIDE

Electrical

The pump does not operate when turned ON:

• Check the power supply and connections.

Voltage should be between 100 - 130 Vac
for -1 models and between 200 - 240 Vac
for -2 models.

• Check wiring color scheme. See Installa-

tion section or call for technical assistance.

Liquid

The pump operates but does not prime:

• Check for a clogged or loose filter on the

suction valve assembly. Retighten if
necessary.

• Check to see if the pump is too high above

the foot valve assembly (HI 721005) in the
feed tank. This vertical distance should not

4. Switch the pump ON to

the estimated setting and
run for a specific amount
of time (e.g. 1 minute).
Count the number of
strokes, length of time,
and volume pumped.

Note: It is suggested that you run the test for

as long as possible to maximize the
accuracy.

For example, if at the maximum setting of
100% you find you pumped 200 mL in one
minute, your hourly output would be 12 li-
ters/hour (200 mL x 60 min. = 12000 mL/hr).
If your application called for 9 liters/hour,
turn the Flow Rate Control to 7 (9/12). Run
the test again to verify the results.

Operating Pressure and Back Pressure

Operating pressure is a combination of back
pressure plus all of the other resistances to
flow present in your system.
BlackStone Pumps are designed to dose their
rated output at the operating (rated) pressure.
Therefore, rated pressure of the pump you
install should be close to operating pressure
present in the system.
Too little back pressure can cause the pump
to overdose.
To prevent this from happening on a low back
pressure installation, a spring has been added
to the discharge/anti-siphon valve assembly
(HI 721004).
When pumping into a high back pressure,
the spring should be removed.

Actual Flow Rate

The actual flow rate depends upon the oper-
ating pressure which includes resistance at
the injection fittings, hose and piping, the
chemical viscosity and suction lift. The Flow
Rate Control adjusts the flow up to 100% of
the rated output. Less back pressure will
increase the output, more will decrease it.
To determine the correct setting for your
application, use the following procedure.
1. Be sure that the pump is primed and that

the output connections are completed at
the injection point.

2. Place the foot valve assem-

bly (HI 721005) in a gradu-
ated container with 500
mL of the solution to be
dosed.

3. Switch the pump from OFF

to the 100% setting and
run until the system has
been fully reprimed. Switch
OFF and refill the container
to the 500 mL level.