Hot gas cycle has two functions in that it prevents gas that can condense in the " hot line of the gas pipeline from draining back into the heads of the compressor cycles, and this prevents the oil leaving one compressor from draining down, the head of machine downtime. It is important to reduce pressure losses in the hot gas lines, because the losses in these lines to increase the required compressor horsepower per ton of cooling and reduce compressor output. The differential pressure to minimize, dimension lines generously to avoid friction loss, but all the same, making sure that the refrigerant line speed sufficient to capture and transportation of oil on all load conditions. In addition, the following directories must be met:
Compressor hot gas discharge line must be connected as shown on Fig. 4.7.
The maximum length of risers to horizontal manifold does not exceed 6 metres.
Collector size must be at least equal to the size of total hot-gas line evaporative condenser.
If water-cooled condensers are interrelated, hot gas collectors must be at least equal to the reset largest compressor.
If evaporative condensers are interrelated, one pipeline should be launched on the evaporative condensers, and the same type of collector, provided the compressors must be installed.
Always stagger and pipelines installation of capacitors.
When the capacitors over compressors, setting of a loop with a minimum depth of 3 feet in hot gas pipeline.
Install manual shutoff valve hot gas line for each compressor.
Water Valves
water-regulating valve control is used with water-cooled condensers. When you install the water valves, the following should be observed:
The condenser water related compressor capacitors should be applied from the total water supply.
Unified automated water taps or more valves in parallel (Fig. 4.8) must be installed in the common water supply.
For the control of pressure pipes of the water valves must be connected to a common line, which in turn must be associated with one of the receivers, or in the total liquid line.
Air-Conditioning 
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