Allied Air Enterprises 4HP16LT - Manual (Page 9)

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 R22 cylinder and the
gauge set valves. Pump the remaining refrigeraant 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 R22 refrigerant drum. Re-install pressure tap
valve cores into the 4HP16LT unit’s service valves.
11. Install a thermal expansion valve approved for use with
R410a refrigerant in the liquid line at the indoor coil.
Refrigerant Metering Device
4HP16LT units are designed for use with TXV systems only.
An R410a system will not operate properly with an R22
metering device.
Expansion valves equipped with Chatleff-type fittings are
available from the manufacturer. See Table 3 for proper
TXV for each unit.
To install an expansion valve (See Figure 9):
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.
506468-01 Page 9 Issue 1004
Table 3
TXV Data
MODEL PART NUMBER
4HP16LT- 24
4HP16LT - 36
H4TXV01
H4TXV02
4HP16LT - 48, -60 H4TXV03
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.
Manifold Gauge Set
Manifold guage sets used with systems charged with R410A
refrigerant must be capable of handling the higher system
operating pressures. The gauges should be rated for use
with pressures 1 - 800 on the high side and a low side of 30”
vacuum to 250 psi with dampened speed to 500 psi. Gauge
hoses must be rated for use at up to 800 psi of pressure
with a 4000 psi burst rating.
Liquid and Suction Line Service Valves
The liquid line and suction line service valves (See Figure
11) and service ports are used for leak teating, evacuation,
charging, and checking charge.
Each valve is equipped with a service port which has a
factory-installed Schrader valve. A service port cap protects
the Schrader valve from contamination and serves as the
primary leak seal.
To Access the Schrader Port:
1. Remove the service port cap with an adjustable wrench.
2. Connect gauge to the service port.
3. When testing is completed, replace service port cap.
Tighten finger tight, then an additional 1/6 turn.
Figure 9