Typical Field-Installed Evaporator Piping: Dual-Circuit Examples - Trane RAUJ-C20 Installation, Operation And Maintenance Manual

The unit has a liquid line check valve that prevents
liquid refrigerant from flowing backward through the
liquid line, filling the condenser, and overflowing to the
compressor during the "Off" cycle. A relief valve is also
installed to prevent the buildup of high pressure in the
liquid line when the unit is off. For proper operation of
the relief valve, the liquid line service valve should not
be in the back seated position but cracked open so the
relief valve (and the fan pressure switch) is open to the
condenser. The line that connects the outlet of the 235
psig relief valve to the liquid line service valve must not
be removed.
For more information, refer to the latest edition of
Application Guide SS-APG012-EN.
• Avoid putting liquid lines underground.
• Route liquid lines as short and direct as possible.
• Slope liquid lines away from the condensing unit 1-
inch for every 10 feet.
• Only insulate liquid lines that pass through heated
areas.
• Wire solenoid valves according to the field
connection diagram for proper operation.
• The liquid line filter drier should be as close to the
solenoid valve as possible.
N N o o t t e e : : If the liquid line riser exceeds 10 feet, refer to
Tube Size and Component Selection,
publication number SS-APG012-EN
Figure 34. Face-split
suction line
(circuit 2)
suction line
(circuit 1)
SS-SVX11K-EN
thermal expansion
valves (TXV)
sight
glass
distributor
Typical Field-Installed Evaporator Piping:
Dual-Circuit Examples
1. Install the TXV directly to the unit liquid connection.
2. Locate the TXV bulb midway between the 90
degrees bends on top of the suction line as
illustrated in Figure 34, p. 51
3. Secure bulb to suction line with two clamps
provided by manufacturer and insulate bulb.
4. Install the Frostat™ according to instructions
enclosed in the kit as close to evaporator as
possible. Although it may look like a trap, it is the
result of going down past the last outlet and turning
to go up.
N N o o t t e e : : All 20 to 60 ton units will require 30% bleed
TXVs. All 80 to 120 ton units will require 15%
bleed TXVs. This does not apply if they are
connected to remote chiller evaporators (see
next section).
Evaporator Coil
with Horizontal-Split
(Standard) Circuiting
liquid line
(circuit 2)
solenoid
valve
liquid line
(circuit 1)
filter drier
I I n n s s t t a a l l l l a a t t i i o o n n M M e e c c h h a a n n i i c c a a l l
or Figure 35, p. 52.
51