Alarms; Run Status (Chiller) - York MILLENNIUM YCAR0315 Installation Operation & Maintenance

Micro Panel
"Recycling pumpdown" is initiated while a compres-
sor is off, able to run, and is in a "No Cooling Load"
state. It can be initiated 45 minutes after either of the
following two conditions are met:
1. Sat Suction Temperature > LCHWT - 0.8°C (1.5°F)
– and –
Ambient Temp > LCHWT - 3.3°C (6°F)
2. The compressor has been idle for 2 hours and Suc-
tion Pressure is greater than the cutout.
The 45-minute timer assures that excessive pumpdowns
do not occur.
After 120 pumpdowns, uninterrupted by a cooling start,
the system will cease to pump down. Pumpdowns will
begin again after a cooling start occurs. This is to pre-
vent oil loss in the system. However, if one system
reaches 120 pumpdowns while the other system is run-
ning for cooling, the running (lead) compressor will be
shut off if the off (lag) compressor is available for start.
At this point, the lead compressor will pump down and
shut off while the lag compressor starts and assumes
the lead. The previously running compressor will now
have 120 pumpdowns available.
A pumpdown failure fault will occur if a system per-
forms three unsuccessful pumpdowns in a row. "Un-
successful" assumes that the system was not able to
pump down to the suction pressure cutout in three min-
utes. The system will require a manual reset to restart.
The following is an example of this safety message:
S Y S # 1 P U M P D O W N
S Y S # 2 P U M P D O W N
Under some circumstances, a pumpdown
may occur when a compressor is called
to come on for cooling. If this occurs, the
compressor will restart to provide cool-
ing after the pumpdown is complete and
the anti-recycle timer times out.
Recycling pumpdown will increase the number of starts
logged in the micro panel; however, it will have no ef-
fect upon the life of compressors.

1.19 ALARMS

Internal contacts are provided in the Power Panel (See
Section 9 [1.12]) which can be used to remotely signal
a warning whenever a fault lockout occurs on any sys-
112
tem, or if power is lost to the control panel. The inter-
nal contacts are normally open (N.O.) and will close
when control power is applied to the panel, if no fault
conditions are present. When a system fault occurs
which locks out a system, the respective contacts open.
If chiller power is lost or a unit fault occurs, such as a
Low Water Temp fault, contacts for all systems will
open.
Contacts for SYS 1 are located on the bottom right of
the microprocessor panel, terminals 23 and 24. SYS 2
contacts are located on terminals 27 and 28. See Fig. 9,
Page 38 for the location of these terminals.
A 28VDC or 120VAC (60 Hz models) or up to 240VAC
(50 Hz models) external alarm circuit (supplied by oth-
ers) may be connected to the alarm contacts. The con-
tacts are rated at 125VA.
F A I L
F A I L

1.20 RUN STATUS (CHILLER)

Chiller Run Status contacts between Terminal 29 and
30 close whenever one of the systems is running.
These contacts are located on the bottom right of the
Microprocessor Board and are rated (voltage and
current) the same as the alarm contacts (Section 9
[1.19]). Also use a suppressor, same as alarm con-
tacts (Section 9 [1.19]). Individual system "Run Sta-
tus" is not available.
FORM 150.52-NM2 (1001)
If any inductive load devices (relay or
contactor) supplied by the user are in
the electrical circuit connected to the
dry alarm contacts, the device must
be suppressed at the load with an
RC suppressor (YORK Part Number
031-00808-000) across the inductive
coil. (Typically, several are supplied
loose with the panel). Failure to install
suppressors will result in nuisance
faults and possible damage to the
chiller.
If the alarm circuit is applied in an
application used for critical duty (such
as process duty or cooling other criti-
cal equipment) and the alarm circuit
should fail to function, YORK will not
be liable for damages.
YORK INTERNATIONAL