Servicing Recommendations; Compressor Replacement - Carrier 38XTZ 007-024 Installation, Operation And Maintenance Instructions

Legend
1 Pulleys
2 Motor and fan shafts must be parallel
3 Straight-edge must be parallel with belt
- Lubrication: Both the motors and the fans have factory-
lubricated and sealed bearings, and need no further
lubrication.
The compressor has its own oil supply, including the
amount for the siphons and refrigerant lines. Oil should
not be added unless a leak has occurred. Always use oil of
the same brand and type that was used for the original
charge.

Servicing recommendations

- Before replacing any of the elements in the cooling circuit,
ensure that the entire refrigerant charge is removed from
both the high and low pressure sides of the unit.
- The control elements of the cooling system are highly
sensitive. If they need to be replaced, care should be taken
not to overheat them with blowlamps whilst soldering. A
damp cloth should be wrapped around the component to be
soldered, and the flame directed away from the component
body.
- Silver alloy soldering rods should always be used.
- If the total unit gas charge has to be replaced, the quantity
should correspond to the original unit gas and liquid
charge, plus the required charge for the refrigerant lines.
The unit should be properly evacuated beforehand.
- During unit operation all panels should be in place,
including the electrical box access panel.
- If it is necessary to cut the lines of the refrigerant circuit,
tube cutters should always be used and never tools which
produce burrs. All refrigerant circuit tubing should be of
copper, specially made for refrigeration purposes.
2 kg or 3 kg
Fig. 50

Compressor replacement

NOTE: This operation must be done by a qualified
technician.
When an internal fault occurs, the compressor must be
replaced. This must be done as detailed below:
- Disconnect the unit from the electrical supply.
- Remove the panels.
- Remove the gas from the refrigerant circuit using recovery
equipment to avoid harming the atmosphere.
- Electrically disconnect the compressor.
- Unbraze or unscrew the suction and discharge lines, taking
care not to damage the rest of the components.
- Remove the fastenings from the compressor.
- Replace the compressor, ensuring that it contains
sufficient oil.
- Check if the oil of the defective compressor contains any
acidity from burnt-out windings.
- If the oil contains acid, this will also be present in the
refrigerant circuit. All the acid must be removed from the
refrigerant circuit, otherwise the new compressor will also
be damaged. In order to remove the acid proceed as
follows:
a) Thoroughly clean the refrigerant circuit using dry
nitrogen in the opposite direction to the refrigerant
flow.
Also carefully clean the separate parts of the
refrigerant circuit.
Install anti-acid filters in the liquid line. Solder the
refrigerant lines. Evacuate the lines and charge them
with refrigerant. Operate the unit for some time.
Remove the oil and check the acidity.
If there is still acid present, repeat the steps above
several times, until no acid exists.
b) If you do not want to carry out the procedure
described under (a), introduce an anti-acid substance
into the refrigerant circuit, if the refrigerant line
length is short.
c) It is also possible to install an anti-acid filter in the
suction lines.
d) Analyse the refrigerant circuit acidity several times
and replace the filters several times until no acidity
exists.
e) Remove the filter from the liquid line in the 38XTZ
units. Install a new filter when no acid remains in
the circuit.
- Once the defective compressor has been replaced by a new
one and the oil has been analysed, proceed as follows:
- Braze or screw in the lines.
- Install a new filter in the liquid line of the 38XTZ
units.
- Connect the compressor according to the wiring
diagram.
- Evacuate the compressor.
- Carry out a leak test. Repair any leaks detected.
- Fill the refrigerant charge indicated on the nameplate,
plus the required charge for the refrigerant connection
lines.
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