Leak Test - Lennox Signature XP21 Series Installation And Service Procedure

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)
PRESSURE]. 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
F AFTER LEAK TESTING DISCONNECT GAUGES FROM SERVICE PORTS.
XP21
B
NITROGEN
HFC−410A
DETECTOR.
Figure 11. System Leak Test
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.
LOW HIGH
MANIFOLD GAUGE SET
TO VAPOR
SERVICE VALVE
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OUTDOOR UNIT
A