Thermo Scientific 7400 Series, Operating And Maintenance Manual

Page: 29 / 60

3-6 7007400 Cryoplus Thermo Scientific
Section 3
Troubleshooting the Alarms
Front
Panel
Alarm
Alarm
Description
/
System
Response
Probable
Cause
Printer
Error
Code
Corrective
Action
LN2
Sour
ce
warning
lamp
and
the
alarm
bars
light,
indicating
that
no
liquid
nitr
ogen
is
flo
wing
to
the
unit.
F
ill
and
B
ypass
valv
es
close.
The
audible
alarm
sounds.
The
remote
alarm
contacts
set
to
activ
ate
in
30
minutes.
This
alarm
will
ring
back
in
30
minutes
if
the
alarm
condition
is
not
corr
ected.
Liquid
N
itr
ogen
tank
is
empty
.
B
ypass
valv
e
is
open
but
the
system
does
not
see
a
¼-
inch
rise
of
LN2
in
20
minutes
P
rinter
prints
E
rr
or
Code
4.
Listen
for
flo
w
of
gas
or
liquid.
Check
the
supply
tank
for
LN2.
R
evie
w
any
changes
or
conditions
which
may
hav
e
impact
on
the
system,
such
as:
Longer
hoses
or
pipes
installed.
F
lo
w
obstr
ucting
or
restricting
fittings
installed.
H
eat
emitting
sour
ce
mo
ved
to
pr
oximity
of
system. N
ote:
An
LN2
Sour
ce
Alarm
is
normally
a
LN2
supply
pr
oblem
and
not
a
fault
of
the
C
ry
o
P
lus
Storage
System.
R
efer
to
Section
1.2
of
this
manual
and
make
sur
e
that
the
unit
is
receiving
4
alarm1a.cdr
Level
Sensor
Fill
V
alve
Bypass
V
alve
Open
V
alve
Bypass Sensor
LN
Source
2
Silence
Set
point
Red
LED's
and
The
audible
alarm
can
only
be
silenced
with
the
key
switch
in
the
Programming
Access
Position.
Return
the
key
switch
to
the
Lock
position
after
silence.
Alarms
do
not
ring
back
except
where
noted.
O
pen
V
alv
e
warning
lamp
and
the
alarm
bars
light.
The
audible
alarm
sounds.
F
ill
and
B
ypass
valv
es
attempt
to
close.
The
R
emote
alarm
contacts
activ
ate
immediately
Alarm
system
resets
if
condition
corr
ects.
P
rinter
prints
E
rr
or
Code
5.
O
pen
V
alv
e
warning
lamp
flashes
and
the
alarm
bars
light.
The
audible
alarm
sounds.
F
ill
and
B
ypass
valv
es
attempt
to
close.
The
command
to
close
has
been
giv
en
to
the
fill
valv
e
but
the
lev
el
of
LN
in
the
unit
continues
to
rise.
The
system
will
go
into
alarm
if
the
liquid
nitr
ogen
rises
mor
e
than
1/4-inch
abo
ve
the
high
limit
setpoint
within
3-10
minutes
after
the
fill
valv
e
closes.
2
The
fill
command
has
been
issued
b
y
the
micr
opr
ocessor
,
See
if
LN2
or
gas
is
still
being
injected
into
the
tank.
If
so,
turn
off
the
tank.
D
isassemble
and
check
the
fill
valv
e
for
ice,
dir
t,
or
other
contaminates.
(R
efer
to
Section
4)
If
is
NO
T
being
injected
into
the
tank
and
the
fill
valv
e
appears
to
be
closed,
verify
that
the
supply
tank
pr
essur
e
is
22
psi
or
less.
A
high
pr
essur
e
LN
sour
ce
may
cause
the
unit
to
ov
er
fill
past
the
high
lev
el
set
point.
N
ote:
This
condition
can
result
when
sev
eral
storage
racks
ar
e
placed
into
the
container
,
raising
the
lev
el
of
the
liquid
nitr
ogen
abo
ve
the
H
igh
Lev
el
set
point,
within
10
minutes
of
a
fill.
LN2
LN2
2
T
urn
off
the
unit
for
10
to
15
minutes,
then
turn
it
back
on.
If
the
alarm
state
persists,
call
the
5 5
Level
Sensor
Fill
V
alve
Bypass
V
alve
Open V
alve
Bypass
Sensor
LN
Source
2
Silence
Level
Sensor
Fill
V
alve
Bypass
V
alve
Open V
alve
Bypass
Sensor
LN
Source
2
Silence