The goal of this video is to show you
safely and correctly how to make a repair on any cabinet produced with R290 refrigerant. The first thing to consider is how do I identify the
cabinet I’m working on uses R290 refrigerant. All R290 equipment is
required to have special labeling throughout the cabinet.
Besides the serial tag label, you will see several labels on the cabinet
interior and the back of the cabinet. Additionally, the condensing unit will also
have several labels on it. It is also required that all R290
equipment have red sleeves over the refrigerant line process tubes. Now that
you properly identified the camera as using R290 refrigerant, also be aware
that the cabinet was manufactured to meet specificULl guidelines and
standards that pertain to R290 refrigerant. Because of this, True requires any part
used for the repair to be an OEM part. For any reason you receive a replacement
part that is not exactly the same as the part you are replacing, stop and call
true before continuing. All the fan motors have a sealed shaft.
All the relay and temperature controls have sealed contacts.
The wire connectors that we use require a certain amount of force to pull the
wires out of the connectors, which eliminates any spark potential. Wire nuts
and crimp type connectors do not meet this requirement — therefore they should
never be used in any R290 cabinet. For all refrigeration repairs, you’re
still required to follow good refrigeration practices. Standard
refrigeration tools will still be required — including oxygen-free dry
nitrogen, a micron gauge, and shut off file for your charging hose. In addition
to these tools, you should also use as short of a refrigerant hoses as possible
as well as a pinch off tool. Now let’s focus on the additional
specialized tools that will be required for R290 service. You will need a
combustible gas leak detector, the safety placard. Use only R290 refrigerant. If
you’re using the 1 pound cylinder supplied by True, you will also need to
use the specialized charging valve. These are the only specialized tools needed to
service an R290 system. True offers these parts individually or as part of
several types of R290 repair kits. Please contact True’s parts department
for pricing and availability. The following procedure should be followed
when doing any type of refrigeration repair. True requires the following good
refrigeration practices. These practices should include but are not limited to:
not leaving the refrigeration system open to the atmosphere for more than 15
minutes, always change the dryer whenever the refrigeration system has been opened,
use a micron gauge and pull a vacuum to a minimum of 500 microns. The
introduction to the refrigeration system of anything other than a flushing agent,
nitrogen, R290, or refrigerant oil is prohibited.
All refrigeration repairs should be made in a well-ventilated area.
The repair we are going to show is replacing a condensing unit on an R290
system that was previously diagnosed with a locked up compressor. Our R290 repair starts with the
service technician turning on its combustible gas leak detector and
leaving it on throughout the unit repair. When you turn on the combustible gas
leak detector, it will have to self calibrate. This will take about a minute.
Once the high-pitched beeping levels off, you can continue. Do not proceed with the
repair into the meter levels off. Put on your safety glasses. The technician should then display the
safety placard in the area he will be making the repair in. Disconnect the unit you’re repairing
from any power source. The service technician will then need to install
temporary piercing valves to allow access to the refrigeration system. To do
this, you may need to trim a portion of the required red identifying sleeves
back and place the temporary valves as close to the crimp on the end of the
process tube as possible. The combustible gas leak detector may go off during this
process. Once the high-pitched beeping levels off you can proceed. after the temporary vows have in place
on the suction process tubes on an r2 90 system the
technician will have to install his manifold gauge set with as short of
hoses as possible on each of the temporary valves once again the
combustible gas leak detector may briefly go off wait for your meter to
level off then proceed with the repair to remove the refrigerant from the
system you can open up both the high and low side lines and release the
refrigerant slowly into the atmosphere doing this will more than likely set the
combustible gas meter off you should immediately shut off both valves on your
manifold and allow any released our 290 refrigerant to dissipate in the
atmosphere once a combustible gas meter levels off you can continue to release
arching any refrigerant repeating this process until all the refrigerant has
been released from the refrigeration system once the refrigerant is out of the
system the technician must use a tubing cutter to cut out any failed
refrigeration component the reason for this is to prevent any possible spread
of contamination and for the overall safety factor for this example the
technician will cut the compressor pull out right where it braises into the
compressor he would then cut the liquid line as it exits the dryer if the
technician is replacing the compressor he will cut the compressor discharge
line right as it exits the compressor instead of the liquid line as it exits
the dryer once the condensing unit has been
removed you’ll set the new condensing unit into place before pulling the plugs
out of the compressor ports be sure all of your refrigeration lines have been
cleaned pre fitted and are ready to be installed
this will minimize the amount of time the refrigeration system is open which
reduces the potential for any moisture to be absorbed into the compressor oil when brazing on an r2 90 system you must
always purge oxygen free dry nitrogen through the system for a minimum of two
minutes before and during brazing we recommend you set the nitrogen regulator
between 3 to 5 psi G start to purge the nitrogen through the
high side process tube allowing it to exit out the suction process too you can now start to braise all the
joints once all brazing is done and the solder
joints have cooled pressurize the system with no more than 200 psi G of oxygen
free dry nitrogen to leak check once we know that there are no leaks
you’re ready to evacuate the duration system release the nitrogen
charge down to about two pounds of nitrogen pressure to ensure that no
outside air is being drawn into the refrigeration system connect your charge hoe
micron gauge that should have already been connected to your vacuum pump as soon as possible to help remove any
moisture from the system continue to pull vacuum until you reach
a minimum of 500 microns once you reach 500 microns you will want to close off
the shutoff valve on the charging hose as well as the high and low side lines
on your manifold gauges remove the charging hose going to your micron gauge
place the adapter valve on the one-pound AR 290 cylinder
be sure to leave the are 290 cylinder in its box you then attach a charging hose to the our
290 adapter valve box on its side on the charging scale
open up the tank valve then bleed the charging hose we recommend placing something heavy on
top of your charging hose so that if the hose gets pulled it will not affect the
scale zero out the scale open up the shutoff valve on the
charging hose our 290 can be added as a liquid or a vapor
open up the hi Alvin said the desired charge has been
weighed in then closed the valve if the system didn’t take its full charge close
the high side valve and start the compressor and allow it to run for a
minute then slowly open the low side valve until fully charged once the
system is fully charged close the adapter valve on the AR 290 cylinder as
well as the shutoff valve on the charging hose allow the unit to run to verify
operation now time to remove both your hoses and
temporary access valves true requires the removal of any excess valves on any
refrigeration system the next step would be to remove the refrigerant that is
trapped in the high side hose to ensure that we have proper charge in the unit
to do this pinch off the high side process tube in front of the access port
next you want to open up the high side valve then slowly open the low side
manifold valve to draw all the refrigerant out of the high side hose
once the pressures have equalized you can close the high and low side
manifolds using a tubing cutter cut the high side process line in front of the
temporary access valve behind a pinch off tool this could cause the
combustible leak detector to go off wait for the combustible gas leak detector to
level off before moving on be sure to crimp the end of the copper tube down so
that it will make it easier to weld test the end of the line with the bubble to
make sure it’s not leaking once the combustible gas leak detector
levels off you’re ready to braise the end of the process to be shot once the process tube cools down remove
the pinch off tool and thoroughly leak check with soap bubbles now you can repeat these steps for the
low-side process tube what’s the final repairs completed if
the red identifying process tube sleeves have been removed
they must be reinstalled once the process tubes have cooled down if you have any questions prior to
working on any system stop and contact throughs
technical service department at 185 5 3 7 2 1 3 6 8 or 1-800 three two five six
one five two