Thermo King Spectrum DE 30-2, Manual, Page: 78 / 140

Refrigeration Maintenance
78
Charging the System
1. Insure that all compartment bulkheads are
open. Ceiling mounted bulkheads should not
be stored close to the evaporator outlets as this
will restrict airflow.
2. Determine the correct charge for the unit as
configured. The actual weight of the charge
may vary somewhat due to length of
refrigerant lines.
3. The unit should still be in Evacuation mode.
Add as much of the charge as possible as
liquid through the discharge service valve and
receiver tank outlet valve.
4. Back seat and crack the discharge service
valve.
5. Back seat the receiver tank outlet valve.
6. Crack the suction service valve.
7. Exit the Evacuation mode by turning the
Zone1/Host On/Off switch Off, and then back
On.
8. Turn all zones On and set all zone setpoints
for the lowest possible temperature to insure
that all zones run in Cool mode. Allow the
unit to start.
9. Cover the condenser as required to maintain
discharge pressure from 325 to 400 psig (2241
to 2758 kPa) and add the remaining charge by
weight as liquid through the suction service
valve.
10. If necessary, continue to add refrigerant until
the ball in the receiver tank sight glass is
floating but is no higher than 1/2 way up the
glass. If they system is overcharged, remove
refrigerant until the ball in the receiver tank
sight glass is floating but is no higher than 1/2
way up the glass.
11. Continue to operate the unit and monitor the
sight glass until all compartment temperatures
are at or below 0 F (-18 C).
12. If the receiver tank sight glass level drops, add
additional refrigerant as required to maintain
refrigerant in the bottom 1/2 of the sight glass.
13. When refrigerant level is correct back seat all
service valves, remove the gauge manifold,
and securely replace valve stem covers with
seals and service port caps before returning
the unit to service.