Lennox International Inc 4HP18LT manual Refrigerant Metering Device, Expansion Valve Systems

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 4HP18LT 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 4SHP18LT unit’s service valves.

11.Install the fixed orifice (or thermal expansion valve approved for use with R410A refrigerant) in the liquid line at the indoor coil.

Refrigerant Metering Device

4HP18LT units are designed for use with TXV systems. Refer to the appropriate following section for information on installing the chosen refrigerant metering device.

An R410A system will not operate properly with an R-22 metering device.

Install the refrigerant metering device as shown in Figure

11.Do not twist cap tubes when loosening the seal nut from the orifice housing. Use wrench to back up the distributor.

Figure 10

Expansion Valve Systems

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

4HP18LT- 24 H4TXV01

4HP18LT - 36 H4TXV02

4HP18LT - 48, -60 H4TXV03

Table 3

To install an expansion valve (See Figure 10 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.

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