Johnson Controls SABROE HeatPAC, Operating Manual

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Operating manual - HeatPAC with reciprocating compressor
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Design and function
3.2.11 By-pass function during start-up
The R717 charge on HeatPAC is very low. HeatPAC is therefore equipped with a by-pass from the bot-
tom of the oil separator to the evaporator. R717 condensed in the oil separator during standstill is lead to
the evaporator through a timer-operated solenoid valve, pos. 2, Fig. 19, which is open during standstill
and for a short start-up period only. The timer can be adjusted in the UniSAB III controller.
Fig. 19: Solenoid valves for oil recovery, oil return and by-pass.
Pos. no. Designation
1 Oil recovery from evaporator, compressor suction
2 Oil recovery from evaporator, discharge gas
3 Oil return from oil separator
4 By-pass function during start-up/equalizing at standstill
3.2.12 WHC circulation system
The Sabroe WHC circulation system is designed to maintain optimum cooling water temperature on heat
pumps and refrigeration compressors with water-cooled top and side covers. The system ensures a con-
stant cooling water temperature thus giving the compressor optimum operating conditions. The system
circulates water (or glycol) during both operation and standstill.
The Sabroe WHC circulation system is a complete system with built-in control. The system has two
functions:
• At standstill the water is circulated and heated in the circuit to prevent condensing of refrigerant
in the compressor while at the same time keeping the oil in the compressor crankcase warm for
operation. The system ensures that the compressor is always ready for start-up.
• During operation water is circulated and cooled in the circuit so that oil and discharge tempera-
tures do not exceed the fixed limits.
The system ensures optimum cooling water temperature and minimum water consumption.
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