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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
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
A IMPORTANT
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)
Page 10
505076M
06/07
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