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
system.
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 copper4o-steel
brazing) which are rated for use with HCFC-22
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
brazing. 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. If required, install a field-provided check expansion
valve (approved for use with HCFC-22 refrigerant) in
the liquid line at the indoor coil.
HP13 units are used in check expansion valve (CTXV)
systems only. See the Lennox Engineering Handbook for
approved expansion valve match-ups and application
information.
Check expansion valves equipped with Chatleff fittings are
available from Lennox. Refer to the Engineering
Handbook for applicable check expansion valves for use
with specific match-ups. See table 3 for valve kits.
Table 3
Indoor Check Expansion Valve Kits
Model Kit Number
HP13-018, -024, -030, -036 LB-85759F
HP13-042, -048 LB-85759G
HP13-060 100188-01
AIMPORTANT
If you install a check expansion valve with an indoor coil
that includes a fixed orifice, remove the orifice before the
check expansion valve is installed. See figure 17 for
installation of the check expansion valve.
// j
DISTRIBUTOR (__ LIQUID LINE
................................_ STUB
NOTE- If installing expansion valve with an indoor coil that in-
cludes a fixed orifice, remove orifice before installing valve.
Figure 17. Metering Device Installation
When checking the unit charge, use a manifold gauge set
that is equipped with "low loss" hoses. Do not use a
manifold gauge set with anything other than a "low loss"
hose. See figure 18 for manifold gauge connections.
DEFROST --....__.._
THERMOSTAT
CHECK EXPANSION VALVE
LOW Hugh
PRESSURE PRESSURE
o s@:,!.
!
i
!
II
!
DISTRIBUTOR OUTDOOR UNIT
REVERSING VALVE
DRIER OUTDOOR
COiL
VAPOR set- SERVICE
vice port J PORT
line
f JJ COMPRESSOR _ valve
CHECK EXPANSION VALVE --
NOTE - ARROWS INDICATE
DIRECTION OF REFRIGERANT FLOW
NOTE - USE GAUGE PORTS ON VAPOR
LINE VALVE AND LIQUID VALVE FOR
EVACUATING REFRIGERANT LINES
AND INDOOR COIL. USE VAPOR GAUGE
PORT TO MEASURE VAPOR PRESSURE
DURING CHARGING.
INDOOR UNIT
INDOOR
COIL
Figure 18. HP13 Cooling Cycle (Showing Gauge Manifold Connections)
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