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Charging Recommendations

Charging liquid in a CONTROLLED manner into the suction side until the system is full. This recommen-

dation does not hold true for reciprocaing compressors where liquid charging into the suction side could cause

severe damage.

Charging Cylinder on Scale Close-up of Scale

Carefully monitor the suction and discharge pressures - ensure that the suction pressure does not fall below

25 psig (1.7 bar) at any time during the charging process.

CAUTION : Manifold Gauge will show cylinder pressure rather than suction pressure if the cylinder valve and

Manifold valve “A” are both open.

There are many ways of charging liquid in a “controlled manner” into the

suction side:-

1. Use valve A on the manifold gauge set

2. Use the valve on the refrigerant cylinder

3. Charge through a Shredder valve

4. Use a hose with a Shredder valve depressor

5. Charge into the suction side at some distance from the compressor

6. All of the above

Charging Procedures -Three phase compressors

The fundamental procedure is the same as for single phase models but the compressor can run in the wrong

direction on starting. If this happens reverse any two phases and start again. Short term reverse rotation will

not damage the compressor.

As compressors get larger the importance of correct eld charging procedures grows exponentially.

Unfortu¬nately larger systems are often eld charged which leads to many infant failures. All Specter

compressors have internal discharge temperature protectors which are very effective in preventing

dangerously high discharge temperatures during charging. The protection module will trip and lock the

compressor out for 30 minutes. It is not normally necessary to wait 30 minutes for the module to reset. When the

compressor has cooled down the module can be reset by breaking the power supply to the control circuit. Very

often the serviceman does not understand why the module tripped and uses a jumper wire to bypass it. He

continues to charge the system and removes the jumper when charging is complete. The compressor may or

may not run with the protector back in the circuit but it is certain that the compressor has been damaged and

premature failure is inevitable.

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McQuay M4MC Especificaciones Pagina 21