Lennox HP29

IV − CHARGINGUnit charge is based on a matching indoor coil andoutdoor coil with a 15 foot (4.5 m) line set. For varyinglengths of line set, refer to table 10.Liquid LineSet Diameter5/16 in. (8mm)3/8 in. (10 mm)TABLE 10Ounce per 5 foot (ml per mm) adjust from15 ft. (4.5 m)*2 ounce per 5 feet (60 ml per 1524 mm)3 ounce per 5 feet (90 ml per 1524 mm)*If line set is greater than 15 ft. (4.5m) add this amount. If line set is less than15 ft. (4.5m) subtract this amountA − Pumping Down SystemCAUTIONDeep vacuum operation (operating compressor at 0psig or lower) can cause internal fusite arcingresulting in a damaged or failed compressor. Thistype of damage will result in denial of warranty claim.The system may be pumped down when leak checkingthe line set and indoor coil or making repairs to the lineset or indoor coil.1 − Attach gauge manifold.2 − Front seat (close) liquid line valve.3 − Start outdoor unit in cooling mode.4 − Monitor suction gauge. Stop unit when 0 psig isreached.5 − Front seat (close) suction line valve.B − Leak Testing (To Be DoneBefore Evacuating)1 − Add small amount of refrigerant (3 to 5 psig) to thesystem.2 − Attach gauge manifold and connect a drum of drynitrogen to center port of gauge manifold.3 − Pressurize the system to 150 psig.CAUTIONWhen using dry nitrogen, a pressure reducingregulator must be used to prevent excessivepressure in gauge manifold, connecting hoses, andwithin the system. Regulator setting must notexceed 150 psig (1034 kpa). Failure to use a regulatorcan cause equipment failure resulting in injury.NOTE−Electronic leak or Halide detector should beused. Add a small amount of HCFC22 (3 to 5 psig(20kPa to 34kPa)) then pressurize with nitrogen to 150psig.C − Evacuating the SystemIMPORTANTThe compressor should never be used toevacuate a refrigeration or air conditioningsystem.1 − Attach gauge manifold. Connect vacuum pump (withvacuum gauge) to center port of gauge manifold. Withboth manifold service valves open, start pump andevacuate indoor coil and refrigerant lines.IMPORTANTA temperature vacuum gauge, mercury vacuum(U−tube), or thermocouple gauge should be used.The usual Bourdon tube gauges are not accurateenough in the vacuum range.2 − Evacuate the system to 29 inches (737mm) vacuum.During the early stages of evacuation, it is desirable tostop the vacuum pump at least once to determine if thereis a rapid loss of vacuum. A rapid loss of vacuum wouldindicate a leak in the system and a repeat of the leaktesting section would be necessary.3 − After evacuating system to 29 inches (737mm), closegauge manifold valves to center port, stop vacuum pumpand disconnect from gauge manifold. Attach an uprightnitrogen drum to center port of gauge manifold and opendrum valve slightly to purge line at manifold. Breakvacuum in system with nitrogen pressure by openingmanifold high pressure valve. Close manifold highpressure valve to center port.4 − Close nitrogen drum valve and disconnect fromgauge manifold center port. Release nitrogenpressure from system.5 − Connect vacuum pump to gauge manifold centerport. Evacuate system through manifold servicevalves until vacuum in system does not rise above.5mm of mercury absolute pressure or 500 micronswithin a 20−minute period after stopping vacuumpump.6 − After evacuation is complete, close manifold center port,and connect refrigerant drum. Pressurize system slightlywith refrigerant to break vacuum.D − ChargingCharging must be done in the cooling mode.If system iscompletely void of refrigerant, the recommended and mostaccurate method of charging is to weigh the refrigerant intothe unit according to the total amount shown on the unitnameplate.If weighing facilities are not available or if unit is just low oncharge, the following procedure applies.Separate discharge and vapor line service ports areprovided outside the unit for connection of gauge manifoldduring charging procedure as well as a suction line serviceport.Page 13