Carrier PERFORMANCE 50VT-A Installation Instructions Manual

Also see for COMFORT 50VT-A: Owner's information manual Owner's information manual Installation instructions

Contents

Carrier PERFORMANCE 50VT-A Installation Instructions Manual Manual pdf 27 page image

27Step 8 — Pressure SwitchesPressure switches are protective devices wired into control circuit(low voltage). They shut off compressor if abnormally high or lowpressures are present in the refrigeration circuit. These pressureswitches are specifically designed to operate with Puron (R--410A)systems. R--22 pressure switches must not be used as replacementsfor the Puron (R--410A) system.Step 9 — Loss of Charge SwitchThis switch is located on the liquid line and protects against lowsuction pressures caused by such events as loss of charge, lowairflow across indoor coil, dirty filters, etc. It opens on a pressuredrop at about 20 psig. If system pressure is above this, switchshould be closed. To check switch:1. Turn off all power to unit.2. Disconnect leads on switch.3. Apply ohm meter leads across switch. You should havecontinuity on a good switch.NOTE: Because these switches are attached to refrigerationsystem under pressure, it is not advisable to remove this device fortroubleshooting unless you are reasonably certain that a problemexists. If switch must be removed, remove and recover all systemcharge so that pressure gauges read 0 psig. Never open systemwithout breaking vacuum with dry nitrogen.Step 10 — High--Pressure SwitchThe high--pressure switch is located in the discharge line andprotects against excessive condenser coil pressure. It opens at 650psig.High pressure may be caused by a dirty outdoor coil, failed fanmotor, or outdoor air recirculation.To check switch:1. Turn off all power to unit.2. Disconnect leads on switch.3. Apply ohm meter leads across switch. You should havecontinuity on a good switch.Step 11 — Copeland Scroll Compressor (PuronRefrigerant)The compressor used in this product is specifically designed tooperate with Puron (R--410A) refrigerant and cannot beinterchanged.EXPLOSION HAZARDFailure to follow this warning could result in personal injury,death or property damage.Wear safety glasses and gloves when handling refrigerants.Keep torches and other ignition sources away from refrigerantand oils.! WARNINGThe scroll compressor pumps refrigerant throughout the system bythe interaction of a stationary and an orbiting scroll. The scrollcompressor has no dynamic suction or discharge valves, and it ismore tolerant of stresses caused by debris, liquid slugging, andflooded starts. The compressor is equipped with an internalpressure relief port. The pressure relief port is a safety device,designed to protect against extreme high pressure. The relief porthas an operating range between 550 and 625 psig differentialpressure.Step 12 — Refrigerant SystemThis step covers the refrigerant system of the 50VT--A, includingthe compressor oil needed, servicing systems on roofs containingsynthetic materials, the filter drier and refrigerant charging.RefrigerantPROPERTY HAZARD, PERSONAL INJURY ORENVIRONMENTAL HAZARDFailure to follow this warning could result in property damageor personal injury or death.This system uses Puron (R--410A) refrigerant which hashigher operating pressures than R--22 and other refrigerants.No other refrigerant may be used in this system. Gauge set,hoses, and recovery system must be designed to handle Puron.If you are unsure consult the equipment manufacturer.! WARNINGCompressor OilThe Copeland scroll compressor uses 3MAF POE oil. If additionaloil is needed, use Uniqema RL32--3MAF. If this oil is notavailable, use Copeland Ultra 32 CC or Mobil Arctic EAL22 CC.This oil is extremely hygroscopic, meaning it absorbs waterreadily. POE oils can absorb 15 times as much water as other oilsdesigned to HCFC and CFC refrigerants. Take all necessaryprecautions to avoid exposure of the oil to the atmosphere.Servicing Systems on Roofs with Synthetic MaterialsPOE (polyolester) compressor lubricants are known to cause longterm damage to some synthetic roofing materials. Exposure, even ifimmediately cleaned up, may cause embrittlement (leading tocracking) to occur in one year or more. When performing anyservice that may risk exposure of compressor oil to the roof, takeappropriate precautions to protect roofing. Procedures which riskoil leakage include, but are not limited to, compressor replacement,repairing refrigerant leaks, replacing refrigerant components suchas filter drier, pressure switch, metering device, coil, accumulator,or reversing valve.Synthetic Roof Precautionary Procedure1. Cover extended roof working area with an impermeablepolyethylene (plastic) drip cloth or tarp. Cover anapproximate 10x10 ft (3x3 m) area.2. Cover area in front of the unit service panel with a terrycloth shop towel to absorb lubricant spills and preventrun--offs, and protect drop cloth from tears caused by toolsor components.3. Place terry cloth shop towel inside unit immediately undercomponent(s) to be serviced and prevent lubricant run--offsthrough the louvered openings in the unit base.4. Perform required service.5. Remove and dispose of any oil contaminated material perlocal codes.Liquid Line Filter DrierThe biflow filter drier is specifically designed to operate withPuron. Use only factory--authorized components. Filter drier mustbe replaced whenever the refrigerant system is opened. Whenremoving a filter drier, use a tubing cutter to cut the drier from thesystem. Do not unsweat a filter drier from the system. Heat fromunsweating will release moisture and contaminants from drier intosystem.50VT-- A