Refrigerant Connections - Lennox ASC Series Installation, Operating And Maintenance Manual

2. INSTALLATION

2.6- REFRIGERANT CONNECTIONS

The unit is supplied with the gas and liquid lines sealed with copper caps out-
side the casing with possibility to install pipe lines (unless the unit is supplied
with the factory precharged refrigerant kit (option) or service valves kit (option).
Standard units are fi lled with Nitrogen gas, which must be removed before any operation on the unit.
As an option, the unit can be supplied with service valves on the gas and liquid lines, with Nitrogen charge
(N ) or refrigerant charge (R-410A).
2
FOR STANDARD UNITS AND UNITS SUPPLIED WITH SERVICE VALVES PROCEED AS FOLLOW:
1. Remove the nitrogen gas through the high and low 5/16" service ports located inside and provide a low vacuum for safety.
2. Remove the caps from the connecting lines.
3. Braze the piping connection lines. Select piping diameter from TABLE 1.
(When brazing refrigerant pipes, nitrogen gas must be supplied into the pipes through the service ports to remove the air).
4. Leak test:
Add nitrogen gas, check that a pressure of 5 kg/cm
by applying soapy water to the pipes which will cause the bubbles to form where there are leaks.
To detect small leaks, proceed as follows:
Add nitrogen gas and check that a pressure of 25 kg/cm
same for at least 24 hours and the fi nal pressure is not less than 10% below the initial pressure.
5. Ensure that the gas line is insulated.
6. Evacuation:
Remove the nitrogen gas, connect the gauge manifold and vacuum pump to both the liquid and gas lines, fully open the gauge
manifold valve and switch on the vacuum pump. Check to make sure the gauge shows a pressure of -750mm Hg. Once a level
of -750mm Hg is reached, keep the vacuum pump running for at least one hour.
7. Refrigerant charge:
- Check TABLE 3.1. and 3.2. for the amount of refrigerant charge, depending on the length and size of the pipe connections.
- Disconnect the vacuum pump and connect to the refrigerant-charging bottle. Open the charging pump and purge the air from
the hose at the pressure gauge manifold.
- Set up the amount of additional refrigerant on the weighing scale, open the high pressure and charged in the liquid state. If
the total amount of refrigerant charge has not been reached because the pressure is balanced, turn off the high side of the
gauge manifold, turn on the unit, and add the remaining amount of the refrigerant charge required slowly through the low side
of the pressure gauge. (With R-410A refrigerant, the charging bottle must be in a vertical position and charged in the liquid
state). Close the pressure gauge, disconnect it from the from the service port of the unit and fi t caps on the service ports. The
unit is then ready to operate.
During installation, keep the gas and liquid pipes covered, in order to prevent humidity and dirt from entering
them.
Take special care that the refrigerant pipes are insulated.
Avoid collapse on lines installation.
FOR UNITS SUPPLIED WITH SERVICE VALVES AND FACTORY PRECHARGED REFRIGERANT KIT, PROCEED AS FOLLOWS:
1. Release the refrigerant pressure from the connecting line through the service
port located in that line.
2. Remove the caps from the connecting lines.
3. Braze the interconnection line to the indoor unit.
4. With the service ports closed, evacuate and connect the vacuum pump to the
5/16" service port on the connecting line to achieve a pressure of -750 mm
Hg; after that, keep the vacuum pump running for at least one hour in order to
provide a vacuum to the connecting lines and the indoor unit. Disconnect the
vacuum pump.
5. Refrigerant charge:
Remove vacuum pump and connect the refrigerant bottle. Check TABLE 2 for
refrigerant charge per meter of copper pipe for the corresponding model.
Adjust the amount of refrigerant on the weighting scale and open the pressure gauge to charge in liquid state (with R-410A
refrigerant, the charging bottle must be in a vertical position and it is important to charge in the liquid state).
Close the pressure gauge, disconnect it from the service port of the unit and fi t the caps.
6. Open the service valves.
7. The unit is ready to operate.
• 18 •
2
has been reached and that there are no leaks in the circuit or brazing
2
has been reached, there are no leaks if the pressure remains the
Installation, Operation and Maintenance manual • ASC/ASH-MIL152E-1217-01/2019
Copper cap
Brazing
Service port
To the indoor
unit
Copper cap
Copper tube to connect to
indoor unit
Refrigerant pipe
lines
Service valve
To outdoor
unit piping