Refrigeration; Refrigerant Type; Piping; Refrigeration Lines - Emerson Liebert GXT3 User Manual

Rev. 0909

Refrigerant Type

The standard refrigerant will be R- unless otherwise
specified on the customer order. Check the serial plate on
the case for information.

piping

The refrigerant line outlets are located under the case.
Locate first the electrical box, the outlets are then on the
same side of the case but at the opposite end. Insulate
suction lines to prevent condensation drippage.

Refrigeration Lines

Liquid
3/8" O.D.
nOTe: The standard coil is piped at
the store tie-in may vary depending on the number of
coils and the draw the case has. Depending on the case
setup, the connecting point in the store may be
or 1 / ". Refer to the particular case you are hooking up.
1
8
Refrigerant lines should be sized as shown on the
refrigeration legend furnished by the store.
Install p-TRApS (oil traps) at the base of all suction line
vertical risers.
pressure drop can rob the system of capacity. To keep the
pressure drop to a minimum, keep refrigerant line run as
short as possible, using the minimum number of elbows.
Where elbows are required, use long radius elbows only.

Control Settings

See the "Case Specs" section of this guidebook for the
appropriate settings for your merchandiser. Maintain these
parameters to achieve near constant product temperatures.
Product temperature should be measured first thing in
the morning, after having been refrigerated overnight.
For all multiplexing, defrost should be time terminated.
Loadmaster valves are not recommended. Defrost times
should be as directed in the Case Specifications section
of this guide. The number of defrosts per day should never
change. The duration of the defrost cycle may be adjusted
to meet conditions present at your location.

Access to TX valves and Drain Lines

Mechanical - Remove product from end of case. Remove
product racks. Remove refrigeration and drain access
panels (labeled). TX valve (mechanical only) and drain are
located under each access panel at end of the case.
electronic - The Electronic Expansion valve master and
slave cylinder(s) are located within the electrical access
panel(s).

electronic expansion valve (Optional)

A wide variety of electronic expansion valves and case
controllers can be utilized. Please refer to EEV and
controller manufacturers information sheet. Sensors for
electronic expansion valves will be installed on the coil inlet,
coil outlet, and in the discharge air. (Some supermarkets
require a 4th sensor in the return air). Case controllers will
be located in the electrical raceway or under the case.

Refrigeration

Suction
5/8" O.D.
/ " (suction); however,
5
8
/ ", / ",
5 7
8 8

Thermostatic expansion valve Location

This device is located on the same side as the refrigeration
stub. A Sporlan balanced port expansion valve model
is furnished as standard equipment, unless otherwise
specified by customer.
expansion valve Adjustment
Expansion valves must be adjusted to fully feed the
evaporator. Before attempting any adjustments, make
sure the evaporator is either clear or very lightly covered
with frost, and that the fixture is within 10°F of its expected
operating temperature.

Measuring the Operating Superheat

1. Determine the suction pressure with an accurate
pressure gauge at the evaporator outlet.
. From a refrigerant pressure temperature chart,
determine the saturation temperature at the
observed suction pressure.
3. Measure the temperature of the suction gas at the
thermostatic remote bulb location.
4. Subtract the saturation temperature obtained in step
No.  from the temperature measured in step No. 3.
5. The difference is superheat.
6. Set the superheat for 5°F - 7°F.

T-STAT Location

T-STATS are located within the electrical raceway. Refer
to diagram below.
TIME CLOCK
T-STAT
9
BALLASTS