Evacuate And Dehydrate The System - Toshiba CARRIER RAV-SP180AT2-UL Installation Manual

Outdoor Unit
8
EVACUATE AND DEHYDRATE THE
SYSTEM
UNIT DAMAGE HAZARD
Failure to follow this caution may result in equipment
damage or improper operation.
Never use the system compressor as a vacuum pump.
Refrigerant tubes and indoor heat exchanger should
be evacuated using the recommended deep vacuum
method of 500 microns. The alternate triple evacuation
method may be used if the procedure outlined below is
followed. Always break a vacuum with dry nitrogen.
SYSTEM VACUUM AND
CHARGE
Using Vacuum Pump
1. Completely tighten flare nuts A, B, C, D, connect
manifold gage charge hose to a charge port of the
low side service valve.
Service Valve
Outdoor Unit
Service Valve
2. Connect charge hose to vacuum pump.
3. Fully open the low side of manifold gage.
Manifold
500 microns
Low side valve
Charge hose
Charge port
(Valve core (Setting pin))
4. Start vacuum pump.
15-EN
CAUTION
Refrigerant
Indoor Unit
Low Side
C
A
D
B High Side
Manifold Gage
High side valve
Charge hose
Vacuum pump
Packed valve at gas side
5. Evacuate using either deep vacuum or triple
evacuation method.
6. After evacuation is complete, fully close the low side
of manifold gage and stop operation of vacuum
pump.
Deep Vacuum Method
The deep vacuum method requires a vacuum pump
capable of pulling a vacuum of 500 microns and a
vacuum gage capable of accurately measuring this
vacuum depth. The deep vacuum method is the most
positive way of assuring a system is free of air and
liquid water.
Deep Vacuum Graph
5000
4500
4000
3500
3000
2500
2000
1500
1000
500
0
Triple Evacuation Method
The triple evacuation method should only be used
when vacuum pump is only capable of pumping down
to 28 in. of mercury vacuum and system does not
contain any liquid water.
Refer to "Triple Evacuation Method chart" and proceed
as follows:
1. Pump system down to 28 in. of mercury and allow
pump to continue operating for an additional 15
minutes.
2. Close service valves and shut off vacuum pump.
3. Connect a nitrogen cylinder and regulator to system
and open until system pressure is 2 psig.
4. Close service valve and allow system to stand for 1
hr. During this time, dry nitrogen will be able to
diffuse throughout the system absorbing moisture.
5. Repeat this procedure as indicated in the chart.
System will then be free of any cotaminants and
water vapor.
– 15 –
Installation Manual
LEAK IN
SYSTEM
VACUUM TIGHT
TOO WET
TIGH T DRY
SYSTEM
1 2 3 4 5 6
MINUTES
7