Lennox XC21 Installation Instructions Manual page 13

BRAZING
CONNECTIONS
1
CUT AND DEBUR
Cut ends of the refrigerant lines square
(free from nicks or dents) and debur the
ends. The pipe must remain round and do
not pinch end of the line.
3
ATTACHED GAUGES
A Connect gauge set low pressure side to liquid line service valve.
B Connect gauge set center port to bottle of nitrogen with regulator.
SERVICE PORT MUST BE OPEN TO ALLOW EXIT
4
WRAP SERVICE VALVE
To protect components during
brazing, wrap a wet cloth around
the liquid line service valve body
and copper tube stub and use
another wet cloth underneath the
valve body to protect the base
paint.
6
BRAZE LINE SET
Braze the liquid line to the liquid line
service valve. Turn off nitrogen flow.
POINT FLAME AWAY FROM
SERVICE VALVE
WARNING Allow braze joint to cool before removing the wet
rag from the service valve. (TEMPERATURES ABOVE 250ºF
CAN DAMAGE VALVE SEALS
IMPORTANT Connect gauge set low pressure side to vapor
line service valve and repeat procedure starting at paragraph 4
for brazing the liquid line to service port valve.
NOTE − Use silver alloy brazing rods with five or six percent minimum silver
alloy for copper−to−copper brazing, 45 percent alloy for copper−to−brass and
copper−to−steel brazing.
POINT FOR NITROGEN
VAPOR LINE
INDOOR
UNIT
LIQUID LINE
2
CAP AND CORE REMOVAL
Remove service cap and core
from both the vapor and liquid line
service ports.
LOW
ATTACH
GAUGES
VAPOR LINE
SERVICE
VALVE
LIQUID LINE SERVICE
A
VALVE
5
FLOW NITROGEN
Flow regulated nitrogen (at 1 to 2 psig) through the refrigeration
gauge set into the valve stem port connection on the liquid line service
valve and out of the valve stem port connection on the vapor service
valve.
NOTE The fixed orifice or check
expansion valve metering device at the
indoor unit will allow low pressure
nitrogen to flow through the system.
7
INSTALL SERVICE PORT CAPS ONLY
After all connections have been brazed, disconnect manifold gauge
set from service ports, cool down piping with wet rag and remove all
wrappings. Do not reinstall cores until after evacuation procedure.
Reinstall service port caps if desired to close off refrigerant ports.
SERVICE PORT
Page 13
USE REGULATOR TO
FLOW NITROGEN AT 1
TO 2 PSIG.
HIGH
B
OUTDOOR
UNIT
NITROGEN
HIGH
LOW
USE REGULATOR TO
FLOW NITROGEN AT 1
TO 2 PSIG.
SERVICE PORT CORE
SERVICE PORT CAP
XC21 SERIES