Carrier GY Betriebsanleitung PDF herunterladen (Seite 14)

SERVICING REFRIGERATION COMPONENTS

Any technician attending the machine for any purpose must be

a fully qualified refrigeration engineer.

WARNING: Before doing any work on the machine ensure that

the power is switched and locked off and that all isolators are

tagged. If a refrigerant circuit is opened, it must be evacuated,

and recharged, after ensuring that the refrigerant is clean and

free from impurities, the filter-drier has been changed and the

unit has been tested for leaks. Before any operation on a

refrigerant circuit, the complete unit refrigerant charge must

be removed with a refrigerant charge recovery group.

General maintenance

Keep the unit itself and the space around it clean and free of

obstructions. Remove all rubbish such as packing materials, as

soon as the installation is completed.

Regularly clean the exposed pipework to remove all dust and

dirt. This makes detection of water leaks easier, and they can

be repaired before more serious faults develop.

Confirm that all screwed and bolted connections and joints are

secure. Secure connections prevent leaks and vibration from

developing.

Check that all insulation joints are securely closed and that all

insulation is firmly in place. Check all heat exchangers and all

pipework.

Confirm regularly that any phase imbalance in the three-phase

power supply is within acceptable limits.

Lubricate the hinges, locks and latches on the electrical control

box doors sparingly.

Liquid refrigerant charging

Checking the charge

WARNING: When adjusting the refrigerant charge always

ensure that water is circulating in the evaporator in order to

prevent any possibility of freezing up. Damage caused by

freezing is not covered by the product warranty.

30GV and 30GY units are shipped with a full normal charge of

refrigerant. Refer to the Physical Data table. If it is nevertheless

necessary to add more refrigerant, run the unit at full capacity

for some time and then add refrigerant until there are no

bubbles in the sight glass. This will generally mean adding

more refrigerant than would be needed to prevent bubbles from

being seen in the sight glass.

WARNING: To ensure proper operation of 30GV and 30GY

units there must be at least 5 K of subcooling as the liquid

refrigerant enters the expansion valve.

30GV and 30GY units use a halogen refrigerant. For your

information, please find below an extract from the official

publication dealing with the design, installation, operation and

maintenance of air conditioning and refrigeration systems and

the training of people involved in these activities, as agreed by

the air conditioning and refrigeration industry.

Refrigerant guidelines

Refrigeration installations must be inspected and maintained

regularly and rigorously by specialists. Their activities must be

overseen and checked by properly trained people. To minimise

discharge to the atmosphere, refrigerants and lubricating oil

must be transferred using methods which reduce leaks and

losses to a minimum.

• Leaks must be repaired immediately

• A valve on the condenser liquid refrigerant outlet line

enables the refrigerant charge to be transferred to the

receiver provided specifically for this purpose.

• If the residual pressure is too low to make the transfer

alone, a purpose-built refrigerant recovery unit must be used.

• Compressor lubricating oil contains refrigerant. Any oil

drained from a system during maintenance must therefore

be handled and stored accordingly.

• Refrigerant under pressure must never be discharged to

the atmosphere.

Recharging liquid refrigerant (30GV units)

CAUTION: 30GV 020 to 059 units are charged with liquid

HFC-407c refrigerant.

This non-azeotropic refrigerant blend consists of 23% R-32,

25% of R-125 and 52% R-134a, and is characterised by the fact

that at the time of the change in state the temperature of the

liquid/vapour mixture is not constant, as with azeotropic

refrigerants. All checks must be pressure tests, and the

appropriate pressure/temperature ratio table must be used for

the interpretation of the values.

Leak detection is especially important for units charged with

refrigerant R-407c. Depending on whether the leak occurs in

the liquid or in the vapour phase, the proportion of the different

components in the remaining liquid is not the same.

NOTE: Regularly carry out leak checks and immediately repair

any leak found.

Undercharge (30GV units)

If there is not enough refrigerant in the system, gas bubbles

appear in the moisture sight glass. There are two possiblities:

• Small undercharge (bubbles in the sight glass, no

significant change in suction pressure).

- After detection and repair the unit can be recharged.

- The replenishment of the charge must be done in the

liquid phase at the liquid line. The refrigerant cylinder

must contain a minimum of 10% of its initial charge.

• Significant undercharge (large bubbles in the sight glass,

drop in suction pressure).

- Small units (charge below 20 kg per circuit).

After detection and repair completely drain the

refrigerant charge, using a refrigerant recovery unit,

then recharge completely, following the precautions

given above.

- Large units (charge above 20 kg per circuit).

After detection and repair completely recharge the

unit as described above, operate it for a few minutes

and then let a specialist carry out a chromatographic

analysis to verify the composition of the blend (range:

R-32: 22-24%, R-125: 23-27%, R-134a: 50-54%).

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