Daikin EWWQ-AJYNN Service Manual

Contents

Daikin EWWQ-AJYNN Service Manual Manual pdf 77 page image

ESIE07-05 Functional ControlPart 2 – Functional Description 2–71324512.18 Capacity ControlIntroduction Cooling capacity control is infinitely variable by means of a capacity slide controlled by amicroprocessor system. Each unit has infinitely variable capacity control from 100% down to 6.25%(four compressor units), to 8.3% (three compressor units) to 12.5% (two compressor units). Thismodulation allows the compressor capacity to exactly match the building-cooling load. The result is adecrease in chiller energy costs, particularly at the part-load conditions at which the chiller operatesmost of the time. Additionally, in some cases there should be the possibility to avoid inertial tank in thewater circuit.FunctiondescriptionThe compressor capacity, moving of the sliding vane, is done by oil pressure. The controller will decideto feed or to drain oil from the capacity control piston compartment in order to load or download.■ When the unload valve (B) is energized, the valve will feed oil to the piston and the slide will moveto the right (loading down).■ When the load valve (A) is energized, the valve (A) will open. The discharge pressure will push thesliding vane to the left and the oil will drain via the loading valve.Number of pulses The compressor load regulation is controlled by a fixed number of pulses to the two solenoid valves,draining and feeding oil in the slide valve chamber.With the default settings, the compressor will load from 25% capacity to 100% capacity in 15 pulses.SuctionPressureLOAD UNLOADDischargePressureCapacity Control MechanismSpringOil SupplyNC NCB AOil VentPistonNumber of PulsesTo Load Comp.Number of PulsesTo Unload Comp.1515