Trane R Series Installation Operation & Maintenance page 47

Installation - Remote Condenser
For best reliability and performance, the RTUA should be matched with the
Trane RTCA. If a non-RTCA condenser is used, the overall performance and
reliability of the RTUA may be affected. Depending on the customer's fan
control, nuisance trips may occur on the RTUA unit, due to head pressure
instability.
If a non-RTCA condenser is a supplied, it must be capable of providing a
minimum of 5 F subcooling at the EXV. The RTUA requires subcooled liquid at
the expansion valves. Without a minimum of 5 F subcooling, the RTUA will
not operate as designed.
Piping should be sized and laid out according to the job plans and specifica-
tions. This design should be completed during system component selection.
NOTE: Use Type L refrigerant-grade copper tubing only.
The refrigerant lines must be isolated to prevent line vibration from being
transferred to the building. Do not secure the lines rigidly to the building at
any point.
All horizontal suction lines should be pitched downward, in the direction of
flow, at a slope of 1/2 in. per 10 feet of run. This allows for larger line size,
which will improve unit efficiency.
Important: Relieve nitrogen pressure before removing end caps.
Do not use a saw to remove end caps, as this may allow copper chips to
contaminate the system. Use a tubing cutter or heat to remove the end caps.
WARNING
Prevent Injury!
When sweating line connections, always provide a sufficient
purge of dry nitrogen through the tubing to prevent the formation
of oxides/scaling cause by high temperature from brazing. Use a
pressure regulator in the line between the unit and the high
pressure nitrogen cylinder to avoid over pressurization and
possible explosion. If any refrigerant or refrigerant vapors are
present a thorough purge with dry nitrogen will prevent the
possible formation of toxic phosgene gas. Failure to follow these
recommendations could result in death or serious injury.
System Configuration
The system can be configured in any of the primary arrangements as shown
in Figures 23, 24 and 25 The configuration and its associated elevation, along
with the total distance between the RTUA and the air-cooled condenser, plays
a critical role in determining the liquid line and discharge line sizes. This will
also affect the field refrigerant and oil charges. Consequently, there are
physical limits which must not be violated if the system is to operate as
designed. Please note the following restrictions:
1. The discharge line sizing is different for different leaving evaporator water
temperatures.
RLC-SVX07A-EN 47