Technical data

4.13 Stop Valves
Stop valves may be provided (by others) in the cooler
and condenser water piping adjacent to the unit to
facilitate maintenance. Thermometer wells and
pressure taps should be provided (by others) in the
piping as close to the unit as possible to facilitate
operating check.
4.14 Flow Switches (Field Installed)
A flow switch or pressure differential control in the
chilled water line(s) adjacent to the unit is an accessory
furnished for connection to the control panel. If a flow
switch is used, it must be directly in series with the chiller
and sensing only water flow through the chiller. The
differential switch must sense pressure drop across the
unit.
4.15 Drain and Vent Valves
Drain and vent valves (by others) should be installed in
the connections provided in the cooler and condenser
liquid heads. These connections may be piped to drain if
desired.
4.16 Checking Piping Circuits and Venting Air
After the water piping is completed, but before any water
box insulation is applied. Tighten and torque (to
maintain between 41 and 82 Nm) the nuts on the liquid
head flanges. Gasket shrinkage and handling during
transit may cause the nuts to loosen. If water pressure is
applied before tightening is done, the gaskets may be
damaged and have to be replaced.
Fill the chilled and condenser water circuits, operate the
pumps manually and carefully check the cooler and
condenser water heads and piping for leaks. Repair
leaks as necessary.
Before initial operation of the unit both water circuits
should be thoroughly vented of all air at the high points.
4.17 Refrigerant Relief Piping
Each unit is equipped with pressure relief valves located
on the condenser, oil separator and evaporator for
relieving excess pressure of the refrigerant charge to
the atmosphere as a safety precaution in case of an
emergency, such as fire.
Refrigerant relief vent piping (by others), from the relief
valves to the outside of the building, is required by code
in most areas and should be installed on all chillers. The
vent line should be sized in accordance with the
ANSI/ASHRAE-15, or local code. The vent line must
include a dirt trap in the vertical leg to intercept and
permit clean out and to trap any vent stack
condensation. The piping MUST be arranged to avoid
strain on the relief valves, using a flexible connection, if
necessary.
4.18 Unit Piping
Compressor lubricant piping and system external piping
are factory installed on all units shipped assembled. On
units shipped dismantled, the lubricant piping to oil
sump and oil cooler and system oil return connections
should be completed, under the supervision of the York
representative, using material furnished. See Form
160.47-N3.1.
035L02381-GB0 4-5
Figure 4.4 Typical Refrigerant Vent Piping from Relief Valves