Service manual

6-4T-294-01
6.4 REFRIGERANT RECOVERY
1. Disconnect the tube clamp connected to the baffle
plate on the liquid line process tube. Remove the
baffle plates covering both process tubes.
2. Installt hepiercingvalve(refertosection6.2)onthe
liquidlineprocesstubeandthesuctionlineprocess
tubes (see Figure 6-4). The valve should be
installedas closeaspossible tothe pinched-offend
of the liquid line and suction line process tubes.
Make sure the tubing is a full round diameter.
3. Installthe3/8to1/4inchadaptertothe1/4inchflare
fittingonthepiercingvalves.Connectthehighside
andl owsideoftheR-134amanifoldgaugesettot he
3/8 inch hose fittings.
4. Connect the refrigerant recovery unit to the center
hose on the m anifold gauge set. Close the piercing
valves, rotating the valve stems fully clockwise.
Following the instructions for your refrigerant
recovery unit start up and open the piercing valves
at the appropriate time by turning the valve stems
counter-clock wise.
5. When the refrige rant is fully recovered from the
system,removetherefrigerantrecoveryunit.Using
drynitrogenbreakthevacuumandbringthesystem
pressuretoaslightlypositivepressureof2to5psig.
6. Remove any positive pressure from the system
through the manifold gauge set and leave the
piercing valve open and the gauge set center hose
open to prevent any pressure build-up i n the
refrigeration system.
WARNING
Before proceeding with the repair make
certain that the stepper motor suction
modulation valve (SMV) is open (refer to
section 6.24) and that there is no positive
pressure in the system.
7. To reduce t he tim e required for evacuation,
dehydrationandrefrigerantchargingofthesystem,
perform the following steps.
S Remove the piercing valves from the liquid
line and suction line process tubes.
S Using the tubing cutter, cut the process tubes
below the pierced hole in liquid line and
suction line process tubes.
S Place the 3/8 inch flare nuts on both process
tubes and flare the tube.
S Connect the 3/8 inch to 1/4 inch flare adapter
and the 1/4 inch swivel elbow x R-134a
refrigerant adapter to the R-134a gauge set.
The refrigeration unit i s now ready for repair, and/or
component replacement, refer to sections 6.6 and 6.7.
8. Pressurize the system with nitrogen and R-134a,
and leak test the entire system.
9. Connectthevacuumpum p tothecenterhoseonthe
manifold gauge set, and thoroughly evacuate the
system to 500 microns.
10. Charge the system with the correct weight (referto
unit model plate, see Fi gure 2-1 for location) of
refrigerant R-134a using an accurate weight scale.
11. Run t est the unit.
When it is determined that the unit is performing
normally, the unit should be sealed to its original
hermetic state as explained below.
12. Usetheprocesst ubepinch-offtooltosealthet ubes
before the 3/8 inch flare assembly (one tube at a
time, if necessary).
13. Ventthelinetothegaugesetandtighten.Checkfor
refrigerant leaks after the pinch-off tool, monitor
thegaugesetforapressurerise.Ifthereisapressure
rise, tighten the pinch-off tool until there is no
pressure rise at the gauge set.
14. Leave the pinch-off tool in place, and remove the
fittings from the liquid line or suction line process
tube.
WARNING
Do not remove the pinch-off tool from the
process tubesuntil thefollowingprocedures
are completed.
15. Using thetubingcutter,cut-offtheexcesstubingas
close to t he pinch-off tool as possible.
16. Useanoxyacetylenetorchtobrazetheexposedend
of the process tubes.
17. Removethepinch-offtool and leak test theprocess
tubes at the brazed end.
18. Install both baffle plates, then connect the tube
clamp to the baffle plate on the liquid line process
tube.