Allied Air Enterprises 4AC16LT manual Refrigerant Metering Device, TXV Data

(It may be necessary to bypass the low pressure switches to ensure complete refrigerant evacuation.)

When the low side system pressures reach 0 psig, close the suction line valve. Disconnect all power to the existing outdoor unit. Refer to the gauges after shutdown to confirm that the valves are not allowing refrigerant to flow back into the low side of the system. Disconnect the liquid and suction lines from the existing outdoor unit.

2.Remove the existing outdoor unit. Set the new R410A unit and follow the brazing connection procedure outlined previously on this page to make line set connections. Do not install the R410A thermal expansion valve at this time.

3.Make low voltage and line voltage connections to the new outdoor unit. Do not turn on power to the unit or open the outdoor unit service valves at this time.

4.Remover the existing R-22 refrigerant flow control orifice or thermal expansion valve before continuing with flushing procedures. R-22 flow control devices are not approved for use with R410A refrigerant and may prevent proper flushing. Use a field-provided fitting to reconnect the lines.

5.Remove the pressure tap valve cores from the 4AC16LT units service valves. Connect an R-22 cylinder with clean refrigerant to the suction service valve. Connect the R-22 gauge set to the liquid line valve and connect a recovery maching with an empty recovery tank to the gauge set.

6.Set the recovery machine for liquid recovery and start the recovery machine. Open the gauge set valves to allow the recovery machine to pull a vacuum on the existing system line set and indoor coil.

7.Invert the cylinder of clean R-22 and open its valve to allow liquid refrigerant to flow in to the system through the suction line valve. Allow the refrigerant to pass from the cylinder and through the line set and the indoor coil before it enters the recovery machine.

8.After all of the liquid refrigerant has been recovered, switch the recovery machine to vapor recovery so that all of the R-

22vapor is recovered. Allow the recovery machine to pull a vacuum on the sytem.

NOTE: A single system flush should remove all of the mineral oil from the existing refrigerant lines and indoor coil. A second flushing may be done (using clean refrigerant) if insufficient amounts of mineral oil were removed during the first flush.

After each system flush, allow the recovery machine to pull a vacuum on the system at the end of the procedure.

9.Close the valve on the inverted R-22 cylinder and the gauge set valves. Pump the remaining refrigerant out of the recovery machine and turn the machine off.

10.Use nitrogen to break the vacuum on the refrigerant lines and indoor coil before removing the recovery machine, gauges, and R-22 refrigerant drum. Re-install pressure tap valve cores into the 4AC16LT unit’s service valves.

11.Install the refrigerant expansion valve approved for use with R410A refrigerant in the liquid line at the indoor coil.

Refrigerant Metering Device

4AC16LT units are designed for use with TXV systems only.

Expansion valves equipped with Chatleff-type fittings are available from the manufacturer. See Table 3 for proper TXV for each unit.

TXV Data

MODEL PART NUMBER

4AC16LT -24, -36 A4TXV01

4AC16LT -48A4TXV02

4AC16LT -60A4TXV02

Table 3

To install an expansion valve (See Figure 9 above):

1.Separate the distributor assembly and remove the piston orifice and used teflon seal. Insert nozzle end of the expansion valve along with a new teflon seal into the distributor and tighten to 20 - 30 ft. lbs. Use backup wrench on all wrench flats. Overtightening will crush the teflon seal and may cause a leak.

2.Attach liquid line portion of distributor assembly along with new teflon seal to the inlet of the expansion valve. Tighten to 20 - 30 ft. lbs. Use backup wrench on all wrench flats. Overtightening will crush the teflon seal and may cause a leak.

3.Connect the external equalizer line to the equalizer port on the suction line and tighten to 8 ft.lbs.

4.Strap the superheat sensing bulb to the suction header.

If installing an expansion valve on an indoor coil that previously used a fixed orifice, be sure to remove the existing fixed orifice. Failure to remove a fixed orifice when installing an expansion valve to the indoor coil will result in improper operation and damage to the system.

506467-01 Issue 1008 Page 8