Kendro HERAcell 150 Operating Instructions Manual Download Page 95

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Operation

Plug in the power cord. The

green

signal lamp indicates that the unit is switched on. Until the in-

put pressure from the connected cylinders, A and B, drops below

0,6 bar

, the

red

signal lamp re-

mains on. The yellow signal lamp indicates the cylinder currently selected.

Open the valve on the gas cylinders and set the pressure regulator on the cylinders for an initial
pressure between

0,9 to 1,1 bar

. The

red

signal lamps should go out. Press the

blue

buttons to

select the desired cylinder (either A or B), and to switch it to the output. After a cylinder has been
manually selected, selection of the remaining cylinder is prevented for approx. 5 seconds. When
the connected device (i.e. a gassed incubator) begins draining gas from the selected cylinder, a
pressure drop may occur at that cylinder's pressure reducer. For this reason, we recommend ad-
justing the output pressure at the pressure reducers to

0,9 to 1,1 bar

when gas is being removed.

An increase in input pressure once gas has been removed has no negative effect on the operati-
on of the unit as long as the maximum pressure of

2 bar

is not exceeded.

If the pressure in the selected cylinder drops below

0,6 bar

for more than 1 minute, the gas cylin-

der monitor automatically switches the supply to the second gas cylinder, and the

red

signal lamp

of the empty cylinder comes on. Simultaneously, the acoustic alarm is switched on and the
alarm output becomes active. Press the "Acknowledge Fault" button to turn the acoustic alarm
off. Should the pressure in the empty cylinder again rise above

0,7 bar

after the unit has already

switched over to the new cylinder, the unit will not automatically switch back to the previously
empty cylinder. However, the empty cylinders

red

signal lamp will go out and its

yellow

signal

lamp will begin flashing, so that the empty cylinder can be identified. After the empty cylinder has
been replaced, the

red

or flashing

yellow

signal lamps will turn off and the alarm output will no

longer be activated.

If, one the alarm has been acknowledged, the empty cylinder is not replaced with a full one, the
acoustic alarm is again activated once the second, full cylinder becomes empty. Whenever the
pressure in one or both cylinders drops below 0.6 bar for more than 1 minute, the alarm output
will be continuously activated.

Possible error messages

Green signal lamp flashing

Switching between gas cylinders is performed by a built-in magnetic valve (bi-stable ma-
gnetic valve). This prevents a switchover from occurring if there is a power failure. The
unit's electronics determines and monitors the position of the magnetic valve. If the unit
does

not

detect any response from the magnetic valve after switching over, the procedure

is repeated up to 10 times. If the magnetic valve fails to switch over despite repeated at-
tempts to do so, the green signal lamp will flash. A flashing

green

lamp can only be reset

by unplugging the unit from the mains power supply.

A yellow signal lamp is flashing

Pressure dropped below

0,6 bar

for longer than one minute. However, after switching over

to a full cylinder, the pressure climbed above

0,7 bar

. This condition can occur if the pres-

sure at the cylinder ouptut drops below

0,6 bar

as gas is being removed. In this case, ad-

just the pressure at the pressure reducer so that it lies between

0.9 to 1.1 bar

when gas is

drained from the cylinder.

Both yellow signal lamps are flashing

This is the same problem as described under 2. above. Here however, the pressure in the
second cylinder has also dropped below 0.6 bar for more than one minute after the switch-
over. In this case, adjust the pressure at both pressure reducers so that it lies between

0,9

to 1,1 bar

when gas is drained from the cylinder.

SPECIFICATIONS

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