Specifications

42 YORK INTERNATIONAL
Purge Count
Following a 1 hour bypass at start, purge exhausts are
counted and displayed in the above messages while
the chiller is running. With the exception of the first hour
after the bypass, the value displayed is the number of
exhausts that have occurred in the “Last Hour”. For ex-
ample, if you walk up to the control panel at 9:11 AM
and press the “DISPLAY DATA” service key and it says
that there have been 7 purges in the “Last Hour”, that
means that there have been 7 exhausts since 8:11 AM.
If you do this at 2:57 PM, it means that there have been
7 exhausts since 1:57 PM, etc. The purge count is reset
to zero by the following:
1. Clearing the excess purge message.
2. Moving the Micro Board program jumper J-57 (CLK
ON/OFF) from “CLK OFF” to “CLK ON” position.
3. Starting the chiller.
The purge count is frozen by the following:
1. When the chiller is not running.
2. An excess purge message is being displayed and at
least 1 full hour of purge exhausts have accumu-
lated.
High Purge Pressure Warning Message
If the purge transducer output is indicating a pressure
of greater than 95.0 PSIA for 255 continuous seconds,
the following message is alternately displayed with the
normal foreground message:
WARNING – HIGH PURGE PRESSURE
When the pressure decreases to less than 95.0 PSIA,
the message is automatically cleared.
Excess Purge Alarm Contacts
A set of alarm contacts are provided on relay board P/N
031-00932-002 at terminals TB4-55/56. These are dry
N.O. contacts rated at 2A inductive @ 250 VAC and 5A
resistive @ 250 VAC.
These contacts can be used to annunciate an excess
purge condition to a remote location. Anytime an excess
purge condition occurs, these contacts close and remain
closed until the excess purge warning message is cleared
by pressing the “WARNING RESET” service key in
“SERVICE” mode. This causes the contacts to open.
MAINTENANCE
In addition to standard Turboguard purge maintenance
requirements, the exhaust orifice should be cleaned and
checked on a yearly basis.
OIL RETURN SYSTEM
OIL RETURN
The oil return system continuously maintains the proper
oil level in the compresor oil sump. (See Fig. 25.)
High pressure condenser gas flows continuously through
the eductor inducing the low pressure, oil rich liquid to
flow from the evaporator, through the dehydrator to the
compressor sump.
CHANGING THE DEHYDRATOR
To change the dehydrator use the following procedure:
1. Shut the stop valves on the condenser gas line, oil
return line to rotor support and inlet end of dehydrator.
2. Remove the dehydrator as follows: Refer to Fig. 26.
a. Remove connection on the inlet end of dehydrator.
b. Place wrenches on the dehydrator outlet and in-
let ends and the flare nut. Loosen the flare nut
and unscrew the dehydrator.
3. Assemble the new filter-drier as follows:
a. Place the outlet and inlet ends of the dehydrator
between the flare nuts.
b. Tighten the flare nuts.
4. Open condenser stop valve and check dehydrator
connections for refrigerant leaks.
5. Open all the dehydrator stop valves to allow the li-
quid refrigerant to flow through the dehydrator and
condenser-gas through the eductor.