1
W
ERIE
REVER
IBLE
HILLER
PE
IFI
ATI
N
ATAL
Controls - FX10 cont
Reversible Chiller Advanced Freeze
etection S
ste
The reversible chiller source and load heat exchan
ers are
rotected b
a multi-sourced temperature lo
ic strate
. The
temperature lo
ic is based upon the re
ri
erant temperature
ensed as the re
ri
erant is about to enter the heat exchan
er;
while enterin
and leavin
water temperatures are bein
used as
orrelatin
actors. The detection scheme is shown as basic and
advanced al
orithms.
Basic Freeze Detection O
eration: “Com
1 or Com
2
Freeze” Alar
This alarm can be tri
ered b
one o
two detection schemes.
Hard Limit Freeze Detection
I
the re
ri
erant temperature drops below the
reeze detection
etpoint b
1.8
F, the associated compressor is locked out
immediatel
re
ardless o
an
other
actors and requires a
m
n
l r
t. NOTE: This Lockout
roduces a “Com
1 or
Comp 2 Freeze” error on the MUI displa
Freeze Detection
The re
ri
erant temperature is compared to the
reeze detection
etpoint
15
F [anti
reeze] or 33
F [water]
ield selectable
, and
i
the temperature
alls below the setpoint
or 30 continuous
econds, the associated compressor will be halted. This
n
ti
n
m
n
l
t
r th
ir
t tw
min
t
ompressor operation. Three such events in 60 minutes will
tri
er a compressor lockout that requires a manual reset.
NOTE: This Lockout
roduces a “Com
1 or Com
2
Freeze” error on the MUI displa
In addition to the above:
Entering Water Temperature In
luence
I
the enterin
water temperature o
the evaporative heat
xchan
er is within 10
F o
the
reeze setpoint, the previousl
mentioned two minute dela
will be eliminated. This allows the
reeze detection to operate immediatel
when the compressor
tarts based on enterin
water temperature.
Leaving Water Temperature Influenc
I
the leavin
water temperature o
the evaporative heat
xchan
er is within 10
F o
the
reeze setpoint, the previousl
mentioned 30 second dela
will be
in to be proportionatel
educed, endin
at a 1 second dela
when the leavin
water
temperature is 1.5
F above the
reeze setpoint.
Dua
Circuite
Heat Exc
an
er Protectio
A low temperature condition on either re
ri
erant circuit will
revent the start o
both compressors. I
the low temperature
ondition exists
or 5 minutes when both compressors are
o
, a lockout is tri
ered
or both compressors. However,
i
or instance both compressors are operatin
and circuit
1 experiences a re
ri
erant temperature below the
reeze
detection setpoint such that compressor 1 is halted,
ompressor 2 will not be halted as a result.
Advanced Freeze Detection O
eration
Pre Freeze” Alar
redictive freeze condition detection
I
the re
ri
erant temperature is within 7.2
F o
the
reeze
detection setpoint, the predictive
reeze detection al
orithm is
nabled, and i
the lo
ic determines that a
reeze condition is
ikel
to happen based on current conditions, the compressor o
the involved re
ri
erant circuit is immediatel
stopped. Three
3
uch events in 60 minutes will tri
er a compressor lockout that
requires a manual reset. In the absence o
such a condition,
the compressor is allowed to operate so that the re
ri
erant
temperature ma
eventuall
be at the threshold o
the
reeze
detection setpoint. NOTE: This Lockout
roduces a “Pre
Freeze” detection error on the MUI displa
Capacit
Limitin
I
the leavin
water temperature drops to 1.8
F above the
reeze detection setpoint, the lead compressor is halted. When
the leavin
water temperature rises to 3.6
F above the
reeze
detection setpoint, it will be allowed to resume operation.
This limitin
is allowed to repeat inde
initel
with no lockout or
indication on the displa
.
I
the leavin
water temperature drops to the
reeze detection
etpoint, the la
compressor is halted. When the leavin
water
temperature rises to 1.8
F above the
reeze detection setpoint, it will
be allowed to resume operation. This limitin
is allowed to repeat
inde
initel
with no lockout or indication on the displa
.
Hi
h Pressur
The hi
h-pressure switch shall be a normall
closed
N
switch
that monitors the s
stems re
ri
erant pressure. I
the input senses
the hi
h-pressure switch is open it must disable the compressor
output immediatel
and count the
ault. The compressor minimum
on time does not appl
i
the hi
h-pressure switch opens. The
ompressor will not restart until the compressor short c
cle time
dela
has been satis
ied.
ow Pressur
The low-pressure switch shall be a normall
closed
N
switch
that monitors the s
stems re
ri
erant pressure. The input 15
econds be
ore compressor start up and then i
nored
or the
irst
2 minutes a
ter the compressor output
B
-2
is enabled. I
the
witch is open continuousl
or 30 seconds durin
compressor