TIF 25176B Refrigerant Recovery Machines 220V-240V 50_60 Hz, metric gauges - Manual (Page 9)

HELPFUL HINTS FOR
REFRIGERANT RECOVERY - cont.
This is probably never noticed in charging, because the
pressure opens the grommet, but during recovery (or with
suction) the deformed grommet severely restricts the flow
of refrigerant.
REFRIGERANT RECYCLING
Current regulations state that used refrigerant shall not be
sold, or used in a different owner's equipment, unless the
refrigerant has been laboratory analyzed and found to
meet the requirements of ARI 700 (latest edition). As a
result, recycling and verifying ARI 700 conformance isn't
economically justified in most cases. It's still a great idea
to do as much cleaning of refrigerant going back into the
same system (or owners system) as possible. We recom-
mend using the largest, high-acid capacity filter, that are
economically feasible. Put these filters on the suction or
inlet side of the recovery unit. Change filters often.
The recovery of large amounts of liquid refrigerant can
sometimes carry with it large quantities of oil, if the sys-
tem being serviced doesn't have an adequate oil separator
installed. If this recovered refrigerant isn't going to be liq-
uid charged back into the same system, you might want to
separate the refrigerant from the oil in order to measure
the oil (to know how much oil to charge back into the sys-
tem). Refrigerant sent back for reclaim does not need to
have the oil removed. One of the simplest and most cost
effective ways to achieve this is to use a 30 or 50 lb. tank
in line with your recovery machine. Connect the system to
the liquid port of the tank, then from the vapor port of the
tank connect to the input of your recovery machine. A sec-
ond tank, for storing refrigerant, should then be connected
to the output of the recovery machine. If you encounter
large amounts of liquid you will need to put a band heater
around the first tank. When the recovery job is complete
the oil can be removed, from the first tank, by applying a
small amount of pressure, using nitrogen, to one of the
ports and extracting the oil from the other. If you are going
to remove the oil from the vapor port you will need to turn
the tank upside down. Always wear safety glasses when
performing this operation as the oil may be acidic and
could cause severe burning.
KEEPING THE DIRT OUT
During the recovery process your recovery machine can
be exposed to debris that can, potentially, damage it. This
includes brazing spatter and copper/ brass slithers. Further
contamination can be introduced from the refrigerant stor-
age tanks. To prolong the life of your recovery machine,
always use an inline filter at the inlet Port.
Whenever you are charging a system from a recovery
cylinder it is a good idea to use an in-line filter to protect
the system from contamination. Again, change your in-line
filters often.
GETTING THE LIQUID OUT
See diagram on page 13 of this manual
Push/pull is a method of removing bulk liquid from a sys-
tem using the pressure differential created by the recovery
machine. Push-pull will generally not work on smaller sys-
tems because there is no bulk liquid reservoir to create a
siphon from.
Push-pull is mostly used on systems with a receiver tank
or those with greater than 20 lbs. of refrigerant, or when
transferring from one tank to another. The rate of liquid
transfer is very much dependent on hose size, with larger
hoses providing much better throughput.
Another trick is to cool the tank, if it's partially filled, prior
to or during recovery. This operation will lower the pres-
sure in the storage tank and therefore speed up recovery.
There must be a minimum of 5 lbs of liquid refrigerant in
the tank you wish to chill. This operation can be performed
prior to or during the recovery. See the two set up dia-
grams and procedures on page 13-14 of this manual.
There is nothing magic here, you are simply using your
recovery machine to make a refrigerator where the tank is
the evaporator. By throttling the output valve, you're effec-
tively creating a capillary tube or an expansion device, but
you need to adjust the back pressure to suit the conditions
and the refrigerant. Five to ten minutes of chilling can pro-
duce some very dramatic tank cooling, depending on the
conditions. If there are any non condensables in the tank
this process will not work. The greater the quantity of
refrigerant in the tank the longer the process will take.
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