System Evacuation - Thermo King MD-200 MT Manual De Instalación

CAUTION: Do not evacuate unit until it is leak free. Unit with less than
full refrigerant charge should be leak checked and all leaks must be
repaired.
NOTE: Use of Thermo King Evacuation Station P/N 204-725 and Evacuation
Station Operation and Field Application Instructions (TK-40612) is required.
NOTE: Electrical controls must be set up throughout this procedure as
described in "Electrical Control Set-Up" on page 81.
1. Recover any refrigerant to 0 psi (Regulations may require recovery machine
to pull system pressure lower than 0 psi).
2. Before connecting refrigerant hoses to unit, close valves V1 and V4 on
evacuation system and turn micron gauge ON.
3. Back seat suction, discharge and receiver tank service valves. Attach
evacuation hoses to these three valves (check condition of hose seals).
4. With service valves fully back seated, turn evacuation pump ON and open
valve V1 (V2 and V3 should also be open). Micron gauge should move to a
deep vacuum.
5. Open valve V4. Micron reading will rise. If micron gauge returns to reading
less than 500 microns, proceed to step 6. If micron reading remains high, a
leak exists at hose fittings or packing glands. Locate and correct problem.
Packing glands that do not seal can be corrected by installing valve stem
covers (see Step 6).
6. If step 5 was successful, close valve V2 to isolate thermistor. Open suction,
discharge and receiver service valves to port. Install brass and steel valve
stem covers (with sealing washers) on service valves and tighten. Let
vacuum pump continue to operate.
7. After 5 minutes of evacuation, open valve V2 to access thermistor and
micron gauge. Micron reading now shows system pressure.

System Evacuation

8. Evacuate system to 500 microns or lowest achievable level between 500 and
1000 microns. Multi-Temp units should be evacuated for an additional hour
once 500 microns is reached.
9. When acceptable micron level is achieved (500 to 1000 microns plus one
hour for Multi-Temp units), close valve V1 to isolate pump. Turn pump
OFF.
10. Observe reading on micron gauge after 5 minutes have elapsed. Vacuum rise
should not exceed 2000 microns. If vacuum level exceeds 2000 microns after
5 minutes, leak is present or additional evacuation time is required.
11. If vacuum level is acceptable, start pump and open valve V1 to evacuate
pressure rise (5 minutes).
12. With vacuum pump running, back seat suction service valve. Observe
micron gauge and continue to operate vacuum pump until an acceptable
micron level is achieved.
13. Close valve V1 and stop pump. Observe micron gauge to confirm that
system remains in a deep vacuum. Close valve V4. Unit is ready to charge.
A.
B.
C.
D.
Legend for Evacuation and Charging Diagram below.
V-4 E.
V-3 F.
V-2 G.
V-1 H.
Eng
Two Stage Vacuum Pump
To AC Power
Micron Gauge
Thermistor
83