12.09.05 rev 1.0
43
49.
Charging the Compressor Single Refrigeration
Instructions on how to charge the refrigeration system with R134a gas.
NOTE: These instructions are only for trolleys with Danfoss compressors.
IMPORTANT ADVICE - It is essential that only fully qualified, licensed Refrigeration Mechanics attempt the following
procedures. All equipment used to service the system must have been used exclusively for R134a refrigerant (including the
connection hoses) and not with any other refrigerant. It is also important to filter the refrigerant gas from the charging cylinder
to eliminate any impurities.
How to charge the gas in the refrigeration circuit - There are two cases where charging may be necessary – first, refrigerant has
to be added to “top-up” the circuit and second, to charge the system when there has been a complete loss of the refrigerant
charge.
Partial Charge: Set the refrigeration temperature with the touchpad to 1°C and start the refrigeration. When the display
indicates 1 degree the expansion temperature must be –22 / -24 degrees. If these values are different, charge the refrigerant gas
until the value described above is reached.
Complete Charge: When the compressor has been changed or a gas leak repaired, it is very important to ensure a full vacuum
is achieved before recharging. The vacuum operation must last at least 30 minutes and should be continued for up to 60
minutes. To be certain that the circuit is completely vacuumed, monitor for another 45 minutes. After turning off the vacuum
pump the manometer needle should oscillate less than 0.2 to 0.3 bar (3 to 4.5 psi).
For new installations, when the vacuum cycle is complete, the manometer needle must remain steady after the pump is turned
off.
When the vacuum cycle is complete, the refrigerant charge can start. With the compressor turned off slowly charge the system.
About 50 grams (2.5 oz.) of gas will be needed to saturate the circuit. Insert the gas from the charging valve put on the high-
pressure side. The complete charge is 180 grams (about 6,34 oz.). To finish the charge, close the manifold-charging valve and
start the compressor. After running approximately half minute, very slowly add more refrigerant until the complete charge of
180 grams is reached.
Calibration: Set now the refrigeration temperature at 1°C and start the refrigeration. When the display indicates 5-6 degrees
monitor the expansion temperature that must be –22 / -24 degrees. If these value is lower (-30, -40 and so on) add a small
quantity of refrigerant, if this value is more (-15, -10 and so on), remove a small quantity of refrigerant and wait a couple of
minutes until the expansion temperature settles. It should settle to –22 / -24 degrees. If settles to a different value repeat the
procedure described above.
To Next Page
Loading...
