Hanna Instruments bl 7917 User Manual

overtightening these parts as this could cause damage to the seats
and threads.
If a hose is used, it should be securely fastened to columns, walls,
braces, etc. This will ensure that the hose connection will remain tight
and leak free. Shield the hose from direct sunlight. Sunlight can
cause an autocatalytic reaction with some chemicals and weaken the
hose walls.
The arrow on the pump head indicates the direction of chemical flow
and should always point upwards (vertically). Never position the
pump horizontally with suction and discharge valves horizontal.
Locate the pump in an area out of the reach of children and pets.
All pumps undergo stringent tests to ensure that they comply with
their stated specifications and are calibrated at the maximum rated
pressure.

GENERAL DESCRIPTION

The BL 7916 and BL 7917 Control/Pump System offer respectively a
pH and ORP monitoring system with proportional control of a
diaphragm pump and an LCD readout.
Features include:

• Two advanced instruments in one compact unit
• Proportional control for precisely maintained set-points
• Rugged construction with a one-piece casing and a transpar-

ent cover to protect controls and terminals

• Chemically resistant non-clogging pump head and superior

materials for all components in contact with the chemicals
being dosed (see page 32 for details)

• Convenient installation with all controls on front panel
• A solenoid-driven pump
• Automatic overheat protection and a built-in LCD display
• Alarm output: the alarm of the BL 7916 will be activated if

the measured pH value is 2 pH units higher or lower than the
setpoint. BL7917's alarm will activate if the mV value is
200mV higher or lower than the setpoint.

• Auxiliary dosing contacts. This will drive other equipment such

as mixers, priming pumps, etc.

Unplug the instrument from the power supply before

replacing the fuse or making any electrical connections.