Refrigerant Connections - Lennox FLATAIR KFC Series Installation And Operating Manual

2.- INSTALLATION

2.7.-REFRIGERANT CONNECTIONS

The units are supplied with gas and liquid lines sealed with copper covers, and located 60mm from casing
Cupper cover
Brazing
The units are supplied with nitrogen gas, this must be removed
1º Remove the nitrogen gas, through the high and low ¼" service ports locate inside, from both indoor and outdoor
units.
2ª Remove the covers from connecting lines.
3ª Braze the piping connection lines. Refer to installation manual to select the diameter of the lines.
(When brazing refrigerant pipes, is necessary to supply nitrogen gas through the service ports into the pipes to
remove the air)
4º Leak test:
- Add nitrogen gas and check 5 kg/cm2 pressure has been reached, and verify there are not leaks in the circuit
or brazing, applying soapy water on pipes, because the leaks cause soapy water to form bubbles.
To detect small leaks proceed as follow:
Add nitrogen gas and check 32 kg/cm2 pressure has been reached, there is not leak if pressure remain the same
at least during 24 hours and final pressure is not less than 10% from the initial pressure.
5º Be sure gas line is isolated
6º Vacuuming.
Remove the nitrogen gas, connect the gauge manifold and vacuum pump to both liquid and gas line, fully open
the valve of the gauge manifold and switch on the vacuum pump. Check to make sure the gauge shows a pressure
level of –750mm Hg, after a level of –750mm Hg is reached, keep on the vacuum pump at least during an hour.
7º Refrigerant charge
- Refer to installation manual to verify amount and type of refrigerant which must be charged, and the total
amount to be added must be calculated considering the refrigerant charge of the unit, and also the length and sizes
of the refrigerant piping.
- Disconnect the vacuum pump and connect to the refrigerant-charging cylinder. Open the charging cylinder
and purge the air from the hose at the gauge manifold.
- Set up the amount of additional refrigerant on the weighing scale, open the high pressure (liquid) and low
pressure side (suction) of the gauge valve to start the process of refrigerant from outdoor unit. If the total amount
of refrigerant charge have not been reached, because balance pressure, turn off the high side of the gauge manifold,
turn on the unit, and add slowly though low side of the gauge the remain amount of the refrigerant charge needed.
(With R-407C refrigerant, the charging cylinder must be on horizontal position and it is important to charge
in liquid state)
Close the sides of gauge valve from service port of the unit, put the covers on service ports. Then the unit is ready
to work.
During installation operations, keep gas and liquid pipes covered, in order to provent humidity
and dirt, get into them.
Take special concern about refrigerant pipes are isolated.
60
Gas
Terminal block
Líquid
and then proceed as follow:
17
Service ports