Refrigeration; Refrigerant Type; Piping; Refrigeration Lines - Hussmann RDI-27 Installation & Operation Manual

Refrigerant Type

The standard refrigerant will be R-22 unless other wise
specifi ed on the customer order. Check the serial plate on
the case for information.

Piping

The refrigerant line outlets are piped through the rear
of the fi xture at the left hand end when viewed from the
back. Insulate suction lines to prevent condensation from
dripping.

Refrigeration Lines

Liquid
3/8" O.D.
NOTE: The standard coil is piped at 5/8" (suction); however,
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
5 / ", 7 / ", or 11 / ". Refer to the particular case you are
8 8 8
hooking up.
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 refrig erant line run as
short as possible, using the minimum number of elbows.
Where elbows are re quired, use long radius elbows only.

Control Settings

See RDI technical data sheet for the appropriate settings for
your merchandiser. Maintain these parameters to achieve
near constant product temperatures. Product temperature
should fi rst be measured in the morning, after having been
refrigerated overnight. For all multiplexing, defrost should
be time terminated. Defrost length and frequency should be
as directed in the RDI technical data sheet. 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

Evaporator Fans

The evaporator fans are located at the center front of these
merchandisers directly beneath the display pans.
FOR ACCESS TO THE FANS: Remove the right hand deck
pan as viewed from the front of the case.

Refrigeration

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
Suction
controllers can be utilized. Please refer to EEV and
5/8" O.D.
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.

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
specifi ed 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 fi xture is within 10°F of its expected
operating temperature.

Measuring the Operating Superheat

T-STAT Location

T-STATS are located within the electrical raceway.
6
1. Determine the suction pressure with an accurate
pressure gauge at the evaporator outlet.
2. 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. 2 from the temperature measured in step No. 3.
3. The difference is superheat.
5. Set the superheat for 5°F - 7°F.