Lennox XC20-036-230-01 Installation And Service Procedure page 22

LEAK TEST
LINE SET AND INDOOR COIL
1
CONNECT GAUGE SET
A. CONNECT AN HFC-410A MANIFOLD GAUGE SET HIGH PRESSURE
HOSE TO THE VAPOR VALVE SERVICE PORT.
B. WITH BOTH MANIFOLD VALVES CLOSED, CONNECT THE CYLINDER
OF HFC-410A REFRIGERANT TO THE CENTER PORT OF THE
MANIFOLD GAUGE SET.
NOTE - LATER IN THE PROCEDURE,
THE HFC-410A CONTAINER WILL BE
REPLACED BY THE NITROGEN
CONTAINER.
2
TEST FOR LEAKS
AFTER THE LINE SET HAS BEEN CONNECTED TO THE INDOOR AND OUTDOOR UNITS, CHECK THE LINE SET CON­
NECTIONS AND INDOOR UNIT FOR LEAKS. USE THE FOLLOWING PROCEDURE TO TEST FOR LEAKS:
A. WITH BOTH MANIFOLD VALVES CLOSED, CONNECT THE CYLINDER OF HFC-410A REFRIGERANT TO THE CENTER PORT OF THE
MANIFOLD GAUGE SET. OPEN THE VALVE ON THE HFC-410A CYLINDER (VAPOR ONLY).
B. OPEN THE HIGH PRESSURE SIDE OF THE MANIFOLD TO ALLOW HFC-410A INTO THE LINE SET AND INDOOR UNIT. WEIGH IN A TRACE
AMOUNT OF HFC-410A [A TRACE AMOUNT IS A MAXIMUM OF TWO OUNCES (57 G) REFRIGERANT OR THREE POUNDS (31 KPA) PRES­
SURE]. CLOSE THE VALVE ON THE HFC-410A CYLINDER AND THE VALVE ON THE HIGH PRESSURE SIDE OF THE MANIFOLD GAUGE
SET. DISCONNECT THE HFC-410A CYLINDER.
C. CONNECT A CYLINDER OF DRY NITROGEN WITH A PRESSURE REGULATING VALVE TO THE CENTER PORT OF THE MANIFOLD
GAUGE SET.
D. ADJUST DRY NITROGEN PRESSURE TO 150 PSIG (1034 KPA). OPEN THE VALVE ON THE HIGH SIDE OF THE MANIFOLD GAUGE SET IN
ORDER TO PRESSURIZE THE LINE SET AND THE INDOOR UNIT.
E. AFTER A FEW MINUTES, OPEN ONE OF THE SERVICE VALVE PORTS AND VERIFY THAT THE REFRIGERANT ADDED TO THE SYSTEM
EARLIER IS MEASURABLE WITH A LEAK DETECTOR.
F. AFTER LEAK TESTING, DISCONNECT GAUGES FROM SERVICE PORTS.
XC20
NOTE - NORMALLY, THE HIGH PRESSURE HOSE IS CONNECTED TO THE LIQUID LINE
PORT. HOWEVER, CONNECTING IT TO THE VAPOR PORT BETTER PROTECTS THE
MANIFOLD GAUGE SET FROM HIGH PRESSURE DAMAGE.
NITROGEN
HFC-410A
Figure 10. System Leak Test
22
LOW HIGH
MANIFOLD GAUGE SET
B
TO VAPOR
SERVICE VALVE
OUTDOOR UNIT
A