FORM 201.10-NM4
93
YORK INTERNATIONAL
YDAS MODELS:
YDAS models are constructed in two sections. One
section contains numbers 1 and 2 refrigerant systems
and their associated evaporator. This section is called
the Master section. The second section contains num-
bers 3 and 4 refrigerant systems and their associated
evaporator. This is called the
Subordinate
section.
Both sec-tions have their own control panel, but only
the master
panel is fitted with a keypad and display.
Operating data for the chiller is stored in three sections:
Common Data for the Whole Chiller, Master Section
System Data, and
Subordinate
Section System
Data. Each
section of data can be accessed
separately or scrolled
through as a continuous loop as
follows:
Pressing the Operating Data key the FIRST time causes
the following message to be displayed:
The Enter key can now be used to scroll through the
common operating data for the chiller followed by the
individual system data for the Master section, then the
individual system data for the
Subordinate
section of the
chiller.
Pressing the Operating Data key a SECOND time, be-
fore pressing the Enter key, causes the following mes-
sage to be displayed:
The Enter key can now be used to scroll through the
operating data starting at the data specific to Systems
1 and 2.
Pressing the Operating Data key a THIRD time before
pressing the Enter key causes the following message
to be displayed:
The Enter key can now be used to scroll through the
operating data starting at the data specific to Systems
3 and 4.
Common Data:
The Common operating data messages and their mean-
ings are as follows:
At any particular point in the loading sequence, the mi-
cro will decide which section of the chiller will load next
and which will be held at a fixed (balanced) load state.
The above message indicates that in this case
the
subordinate
section is being held in balance and the
master section
will be allowed to load at the next load
pulse.
The master and
subordinate
sections of the chiller
each have
their own loading and unloading timers.
These two mes-sages show the time remaining on the
Master Section
Load Timer and Unload Timer followed
by the
Subordinate
Sec-tion Load Timer and Unload
Timer. These Timers con-stantly recycle and are
used in conjunction with firate
controlfl and
fitemperature deviation from setpointfl to
determine
when loading should occur.
NOTE:
These timers may appear not to count accord-
ing to actual time. This is normal as a result of
the micros algorithm compensating for chang-
ing loading requirements.
This message advises which section of the chiller is
acting in lead; in this case, the Master Section, consist-
ing of Systems 1 and 2.
This message shows which system is in lead for each of
the two sections of the chiller; in this case, System 1 for
the Master Section and System 3 for the
Subordinate
Section.
P R E S S
E N T E R
T O
D I S P L A Y
M A S T E R
D A T A
P R E S S
E N T E R
T O
D I S P L A Y
S
U B
D A T A
L O A D
M A
S
T
E
R
S
U B
B A L A N C E
M A S T E R
L O A D
1 0 S E C
T I M E R S
U N L O A D
4 0 S E C
L O A D
1 0 S E C
S
U B O R D I N A T E
T
I
M E
R
S
U N L O A D 4 0 S E C
L E A D
P A N E L
I S
M A S T E R
S Y S T E M
1 & 2
L E A D
S Y S
I S
1
L E A D
M A S T E R
S
U B
S Y S
I S
3
P R E S S
E N T E R
T O
D I S P L A Y
C O M M O N
D A T A
