110
Electronic Vacuum Gauge
Copeland recommends charging liquid in a CONTROLLED manner into the suction side until the
system is full. This recommendation does not hold true for reciprocating 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 field charging procedures grows exponentially.
Unfortunately larger systems are often field 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.
To Next Page
Loading...
Need help?
General
