Labconco PURICARE Procedure Station Models 34812xx - Manual (Page 180)

Page 180 of 197
Generally, the Labconco provided contacts can switch very low amounts of electrical
current, so to control high power, line-operated devices, the Labconco contacts must be
used to control yet another set of contacts that are rated for the actual load being
switched.
The wiring diagram indicates that the “Blower On” contacts are located at J4-pins 3 & 4
while the Airflow Alarm contacts are located at J4-pins 1&2.
Relay Contact #1 …….the “BLOWER ON” contact
This set of contacts (dry contacts pins 3 & 4 of J4 on the electrical enclosure) will
indicate when the BSC’s blower is on. On an A2 cabinet, this contact will close/short
once the blower key is pressed to turn the blower on.
However, on a B2 cabinet, the contacts will close on the initial blower turn-on, but then
these contacts must follow the blower action based on the exhaust airflow sensor, since
low airflow will cause the internal blower to shut off.
The generalized circuit shown below indicates how to interface the Labconco contacts to
power a high power device. Note that the Labconco contacts are used to power the low-
power coil of an added external power style relay/contactor—in this case the relay is a
Hasco HAT903ASDC12, and the 12V coil draws only .08Amps (the Labconco +12v is
fused at .5amps, so choose a max. 5 watts coil)