Daikin AGZ 025D Operating & Maintenance Manual

Daikin AGZ 025D Operating & Maintenance Manual Manual pdf 74 page image

74 AGZ 025D through 190D OMM 1166-1Liquid Line Sight GlassThe refrigerant sight glasses should beobserved periodically (a weekly observationshould be adequate.) A clear glass of liquidindicates that there is subcooled refrigerantcharge in the system. Bubbling refrigerant inthe sight glass, during stable run conditions,indicates that the system can be short ofrefrigerant charge. Refrigerant gas flashing inthe sight glass could also indicate an excessivepressure drop in the liquid line, possibly due toa clogged filter-drier or a restriction elsewherein the liquid line.See Table 22 on page 77 for maximumallowable pressure drops. If subcooling is low,add charge to clear the sight glass. Ifsubcooling is normal (15 to 20 degrees F) andflashing is visible in the sight glass, check thepressure drop across the filter-drier.Subcooling should be checked at full load with70F (21.1C) ambient temperature, stableconditions, and all fans running.An element inside the sight glass indicates themoisture condition corresponding to a givenelement color. If the sight glass does notindicate a dry condition after about 12 hours ofoperation, the circuit should be pumped downand the filter-drier changed or verify moisturecontent by performing an acid test on thecompressor oil.Planned Maintenance ScheduleOPERATION WEEKLY MONTHLY(Note 1)ANNUAL(Note 2)GeneralComplete unit log and review (Note 3) XVisually inspect unit for loose or damaged components XInspect thermal insulation for integrity XClean and paint as required XElectricalCheck terminals for tightness, tighten as necessary XClean control panel interior XVisually inspect components for signs of overheating XVerify compressor heater operation XTest and calibrate equipment protection and operatingcontrols XMegger compressor motor * XRefrigerationLeak test XCheck sight glasses for clear flow XCheck filter-drier pressure drop (see manual for spec) XPerform compressor vibration test XAcid test oil sample XCondenser (air-cooled)Clean condenser coils (Note 4) XCheck fan blades for tightness on shaft (Note 5) XCheck fans for loose rivets and cracks XCheck coil fins for damage XNotes:1. Monthly operations include all weekly operations.2. Annual (or spring start-up) operations includes all weekly and monthly operations.3. Log readings can be taken daily for a higher level of unit observation.4. Coil cleaning can be required more frequently in areas with a high level of airborne particles.5. Be sure fan motors are electrically locked out.* Never Megger motors while they are in a vacuum to avoid damage to the motor.