Allied Air Enterprises 4AC18LT manual Thermostat Designations, Refrigerant Piping

Thermostat Designations

See unit wiring diagram for power supply connections.

If the indoor unit is not equipped with a blower relay, one must be field supplied and installed.

Do not connect C (common) connection between indoor unit and thermostat except when required by the indoor thermostat. Refer to thermostat installation instructions. C (common) connection between indoor unit and outdoor unit required for proper operation.

Figure 4

1.Install line voltage power supply to unit from a properly sized disconnect switch. Any excess high voltage field wiring should be trimmed or secured away from the low voltage field wiring.

2.Ground unit at unit disconnect switch or to an earth ground. To facilitate conduit, a hole is in the bottom of the control box. Connect conduit to the control box using a proper conduit fitting. Units are approved for use only with copper conductors. 24V Class II circuit connections are made in the low voltage junction box. Refer to Figure 4 for high voltage field wiring diagram. A complete unit wiring diagram is located inside the unit control box cover.

3.Install room thermostat on an inside wall that is not subject to drafts, direct sunshine, or other heat sources.

4.Install low voltage wiring from outdoor to indoor unit and from thermostat to indoor unit (See Figure 5).

5.Do not bundle any excess 24V control wire inside control box. Run control wire through installed wire tie and tighten wire tie to provide low voltage strain relief and to maintain seperation of field-installed low and high voltage circuits.

Refrigerant Piping

If the 4AC18LT unit is being installed with a new indoor coil and line set, the refrigerant connections should be made as outlined in this section. If an existing line set and/or indoor coil will be used to complete the system, refer to this section as well as the section that follows entitled - Flushing Existing Line Set and Indoor Coil.

If this unit is being matched with an approved line set or indoor coil which was previously charged with R-22 refrigerant, the line set and coil must be flushed prior to installation. If the unit is being used with and existing indoor coil which was equipped with a liquid line which served as a metering device (RFCI), the liquid line must be replaced prior to the installation of the 4AC18LT unit.

Field refrigerant piping consists of liquid and suction lines from the outdoor unit (sweat connections) to the indoor coil (flare or sweat connections).

Select line set diameters from Table 2 to ensure that oil returns to the compressor. Size vertical suction riser to maintain minimum velocity at minimum capacity. Recommended line length is 50’ or less. If more than 50’ line set is required, contact Technical Services. Table 2 shows the diameters for line sets up to 100’ although vertical lift applications and trapping requirements need to be reviewed with Technical Services for line sets over 50’.

Installing Refrigerant Line

During the installation of an air conditioning system, it is important to properly isolate the refrigerant line to prevent unnecessary vibration. Line set contact with the structure (wall, ceiling, or floor) may cause objectionable noise when vibration is translated into sound. As a result, more energy or vibration can be expected. Close attention to line set isolation must be observed.

Following are some points to consider when placing and installing a high-efficiency outdoor unit:

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