Stulz CeilAiR Series, Инструкция по установке, эксплуатации и обслуживанию

Страница: 30 / 60

(Mar, 2012)
CeilAiR OHS Series Installation, Operation & Maintenance Manual
Air Technology Systems, Inc.
2-19
2.7.6 Remote Shut Down
NOTE
All wiring must be provided in accordance with local
and national electrical code requirements for Class 2
circuits.
Each unit is provided with a means to remotely shut
down the air conditioning unit. A normally closed
switch rated at 5 amperes at 24VAC is required for
this purpose. Two conductors from the normally
closed switch must be connected to the control
terminal board located within the unit electric box.
Refer to the supplied electrical schematic for proper
wire terminations.
2.8 Refrigerant Charging Procedures
Refrigerant charging procedures vary depending on
the type of refrigerant used in the unit. Before charg-
ing, check the unit nameplate to confi rm the refriger-
ant type. If the unit operates with R22 refrigerant see
section 2.8.1. If R407C is used, see section 2.8.2.
NOTE
Refrigerant charging must be performed by a
journeyman, refrigeration mechanic or an air
conditioning technician.
2.8.1 R22 Refrigerant Charging Procedures
2.8.1.1 Self-Contained Systems
All self-contained water/glycol-cooled units (units that
require no refrigerant fi eld piping) are factory charged
with R22. No fi eld charging is required.
2.8.1.2 Remote Air-Cooled Split Systems (AR/AHU)
Remote air-cooled units are factory equipped with a
dry nitrogen holding charge, which must be removed
before piping and charging the unit.
PREPARING SYSTEM FOR CHARGING
1. Once all connections have been made, pres-
surize the system to 150 psig with dry nitrogen.
Leaks may be detected by checking the standing
pressure.
2. After ensuring there are no leaks, relieve
pressure and evacuate the system. Pull a
vacuum of 50 microns or less using the suction
and discharge service ports and the service port
of the receiver (if applicable). Hold the vacuum
for 2 hours. Ensure no portion of system has
been isolated from the evacuation process
(liquid, suction or discharge lines).
CAUTION
A proper vacuum must be drawn on the refriger-
ant system prior to charging. If this is not done
the refrigerant will combine with the moisture
in the pipes to form an acid that will eventually
cause compressor failure.
FINE TUNING THE SYSTEM CHARGE
2.8.1.2.1 0ºF Fan Cycling and -20ºF Variable
Speed Control
The following instructions are for charging systems
with condenser fan cycling or variable speed control
using R22 refrigerant.
1. Bleed air from hoses and “break” the system vac-
uum by supplying R22 vapor. Supply R22 vapor
to the suction port until the pressure is raised to
about 50 psig. This small holding charge allows
the low pressure switch to “make” through out
the process of fi ne tuning the system charge.
WARNING
Do not add liquid R22 refrigerant to suction
side of system.
2. Referring to Section 3.0, start the system and
use the microprocessor controller to lower
the temperature set-point 3-5°F below room
temperature. This will ensure the cooling mode
stays on during the charging procedure.
CAUTION
An adequate heat load must be supplied to the
unit to ensure a proper charge.
3. Supply R22 vapor to the suction port until the
liquid line sight glass is cleared of all bubbles.
4. After the unit has stabilized, the liquid line sight
glass should be clear and the discharge pressure
should be a minimum of 200 psig. A superheat
reading should be taken near the feeler bulb from
the thermal expansion valve, ensuring the tem-
perature measuring device is well insulated. The
superheat should be approximately 12-15ºF.
5. A sub-cooling reading should be taken on
the output side of the condenser, with the