38
ARTC-SVX005B-EN
Lead Module
By default, the primary module is the lead module (the
module that is the first to be engaged). The lead
module always starts first. When there are no
compressors running, the lead module always keeps its
evaporator or condenser valves open (depending on
the current mode) to allow for chilled water or hot
water circulation.
The indicator reads YES or NO to indicate if the module
is currently the lead module.
•
P
Prriim
ma
arry
y O
On
nlliin
ne
e - This applies to secondary
microprocessor controllers only.
•
L
LE
ED
D IIllllu
um
miin
na
atte
ed
d G
Grre
ee
en
n - The secondary
microprocessor controller is communicating with
the primary microprocessor controller.
•
L
LE
ED
D IIllllu
um
miin
na
atte
ed
d G
Grra
ay
y - The secondary
microprocessor controller is not communicating
with the primary microprocessor controller.
•
S
Stta
an
nd
d--a
allo
on
ne
e - A chiller/heater that consists of only
a single module always operates in Stand-alone
Mode since the primary microprocessor controller
does not have subordinate secondary modules with
which to communicate. A module in a multiple-
module chiller/heater operates in the stand-alone
mode whenever it does not meet either primary
module or secondary module operating conditions.
A module temporarily forced to operate in the
stand-alone mode controls cooling and heating
temperatures locally based on:
–
Its evaporator and condenser EWT and LWT.
–
Its cooling and heating and simultaneous mode.
–
Its control temperature sensor selection.
The module runs temporarily in this mode until
normal primary and secondary operation is
restored.
•
S
Se
ecco
on
nd
da
arry
y M
Mo
od
du
ulle
e - A module acts as a secondary
module when
–
Its microprocessor controller has been assigned
the IP address from the secondary address
range.
–
It is communicating with primary module.
–
The primary module exists on the network. The
primary microprocessor controller meets
primary module conditions.
Mode Status
There are six possible values:
•
S
Siim
mu
ulltta
an
ne
eo
ou
uss - The module is in simultaneous
mode.
•
H
He
ea
attiin
ng
g - The module is in heating mode.
•
C
Co
oo
olliin
ng
g - The module is in cooling mode.
•
S
Sw
wiittcch
hiin
ng
g tto
o S
Siim
mu
ulltt - The module is switching to
simultaneous mode.
•
S
Sw
wiittcch
hiin
ng
g tto
o H
He
ea
att - The module is switching to
heating mode.
•
S
Sw
wiittcch
hiin
ng
g tto
o C
Co
oo
oll - The module is switching to
cooling mode.
Heat Exchanger Indicators
This displays each heat exchanger (evaporator,
condenser, or source) inlet and outlet temperatures as
well as the condition of its isolation valves.
Refrigeration Indicators
The refrigerant temperatures and pressures are
displayed: suction pressure, discharge pressure,
suction temperature, and suction super heat
temperature.
Solenoid ‘E’
This is the solenoid valve installed at the evaporator
heat exchanger inlet. It opens when compressors are
running in simultaneous or cooling mode.
Solenoid ‘S’
This is the solenoid valve installed at the source heat
exchanger inlet. It opens when compressors are
running in heating mode.
EX Valve
This indicates the position of electronic expansion
valve.
D1/D2/S1/S2
These are the discharge and Suction Refrigerant
Valves. Depending on the Module Thermal Mode,
valves are automatically positioned as follows:
Table 7. D1/D2 and S1/S2 values
Value
Simultaneously Mode
Cooling only Mode
Heating only Mode
Discharge 1 (D1)
Open
Closed
Open
Discharge 2 (D2)
Closed
Open
Closed
Discharge 3 (D3)
Open
Open
Closed
Discharge 4 (D4)
Closed
Closed
Open
