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Brazing Connection Procedure
1 − Cut ends of the refrigerant lines square (free from nicks
or dents). Debur the ends. The pipe must remain
round, do not pinch end of the line.
2 − Before making line set connections, use dry nitrogen to
purge the refrigerant piping. This will help to prevent
oxidation and the introduction of moisture into the sys-
tem.
3 − Use silver alloy brazing rods (5 or 6 percent minimum
silver alloy for copper−to−copper brazing or 45 percent
silver alloy for copper−to−brass or copper−to−steel braz-
ing) which are rated for use with HCFC22 refrigerant.
Wrap a wet cloth around the valve body and the copper
tube stub. Braze the line set to the service valve.
4 − Wrap a wet cloth around the valve body and copper
tube stub to protect it from heat damage during braz-
ing. Wrap another wet cloth underneath the valve body
to protect the base paint.
NOTE − The tube end must stay bottomed in the fitting
during final assembly to ensure proper seating, sealing
and rigidity.
5 − Install a field−provided thermal expansion valve (ap-
proved for use with HCFC22 refrigerant) in the liquid
line at the indoor coil.
Refrigerant Metering Device
10HPB units are used in check expansion valve systems
only. See the Lennox Engineering Handbook for approved
TXV match-ups and application information.
Check expansion valves equipped with either Chatleff or
flare−type fittings are available from Lennox. Refer to the
Engineering Handbook for applicable expansion valves
for use with specific match-ups. See table 2 for applicable
check expansion valve kits.
If you install a check expansion valve with an indoor
coil that includes a fixed orifice, remove the orifice be-
fore the check expansion valve is installed.
IMPORTANT
Failure to remove RFC orifice when installing an ex-
pansion valve on the indoor coil will result in improp-
er operation and damage to the system.
Table 2
Indoor Check And Expansion Valve Kits
Model
Kit Number
10HPB18
10HPB24
10HPB30
10HPB36
LB−85759F
10HPB42
10HPB48
10HPB60
LB−85759G
See figure 11 for installation of the check expansion valve.
Metering Device Installation
expansion
valve
o−ring
o−ring
strainer
liquid line
stub
distributor
Figure 11
Manifold Gauge Set
When checking the unit charge, use a manifold gauge set
that is equipped with low loss" hoses. Do not use a man-
ifold gauge set with anything other than a low loss" hose.
See figure 12 for manifold gauge connections.
