Installation and Maintenance Manual

RLC-SVX09H-EN 125
RTWD/RTUD Operating Principles
This section contains an overview of the operation of
RTWD Series R chillers equipped with microcomputer-
based control systems. It describes the overall operating
principles of the RTWD water chiller.
Note: To ensure proper diagnosis and repair, contact a
qualified service organization if a problem should
occur.
General
RTWD
The Model RTWD units are dual-compressor, dual circuit,
water-cooled liquid chillers.These units are equipped with
unit-mounted starter/control panels.The basic
components of an RTWD unit are:
• Unit-mounted panel containing starter andTracer
CH530 controller and Input/Output LLIDS
• Helical-rotary compressors
• Evaporator
• Condenser
• Electronic expansion valves
• Water-cooled condenser with integral subcooler
• Oil supply system
• Oil cooler (application dependent)
• Related interconnecting piping.
RTUD
The Model RTUD units are dual compressor, dual circuit
compressor chillers.These units are equipped with unit
mounted starter/control panel.The basic components of
an RTUD unit are:
• Unit-mounted panel containing starter and tracer
CH530 controller and Input/Output LLIDs
• Helical-rotary compressors
• Evaporator
• Electronic expansion valves
• Oil supply system
• Oil cooler
• Related interconnecting piping
Components of a typical unit are identified in Figure 46
and Figure 47, p. 126.
WARNING
Refrigerant under High Pressure! (RTWD
Only)
System contains oil and refrigerant under high
pressure. Recover refrigerant to relieve pressure before
opening the system. See unit nameplate for refrigerant
type. Do not use non-approved refrigerants, refrigerant
substitutes, or refrigerant additives. Failure to recover
refrigerant to relieve pressure or the use of non-
approved refrigerants, refrigerant substitutes, or
refrigerant additives could result in an explosion which
could result in death or serious injury or equipment
damage.
WARNING
Hazardous Voltage!
Disconnect all electric power, including remote
disconnects before servicing. Follow proper lockout/
tagout procedures to ensure the power can not be
inadvertently energized. Failure to disconnect power
before servicing could result in death or serious injury.
Figure 46. RTWD/RTUD components (front view)
Control Panel
Suct
i
o
n
Se
rvi
ce
V
a
lv
e
Evaporator Circuit 1
Eva
p
orator Circuit 2
Oil Separator Circuit 1
Compressor B
Condenser Circuit 1
(RTWD only)
Condenser Circuit 2
(RTWD only)
Suction Service Valve
Starter Panel