Requirements; Refrigerant Piping Connections - Lennox T?CLASS TAA SERIES Installation Instructions Manual

Requirements

These instructions are intended as a general guide and do
not supersede local or national codes in any way. Consult
authorities having jurisdiction before installation.
In addition to conforming to manufacturer's installation
instructions and local municipal building codes, installation
of Lennox air handler units (with or without optional electric
heat), shall conform with the following National Fire
Protection Association (NFPA) standards:
S
NFPA No. 90A
Conditioning and Ventilation Systems
S
NFPA No. 90B
Residence Type
Conditioning Systems
This unit is approved for installation clearance to
combustible material as stated on the unit rating plate.
Accessibility and service
precedence over combustible material clearances.

Refrigerant Piping Connections

TAA series evaporator coils have a holding charge of
nitrogen or dry air. If there is no pressure when the rubber
plugs are removed, check the coil for leaks before
installing. After installation, pull a vacuum on the coil and
line set before releasing the outdoor unit charge into the
system.
PROTECTIVE COIL COVER BETWEEN TXV(S)
AND EVAPORATOR COIL MUST BE REMOVED
BEFORE UNIT START−UP.
Standard for Installation of Air
Standard for Installation of
Warm Air Heating and
clearances must
Figure 1. Protective Coil Cover Removal
Table 1. TAA Series Refrigerant Connections
Models
−072S4S
−090S4D, −120S4D,
and −150S4D
−180S4D, and
−240S4D
For single−stage applications, pipe the upper and lower
evaporator circuits together (does not apply to TAA072).
For two−stage applications, pipe the stage 1 system to the
lower part of the evaporator and the stage 2 system to the
Air
upper part of the evaporator. Table 1 lists piping connection
sizes at the evaporator coil. The line set between the TAA
air handler and outdoor unit should be sized per the
Lennox Refrigerant Piping Guidelines.
take
4. Route piping through either side of the unit.
5. Remove the knockouts from the piping mullion. Install
the rubber grommets into the piping holes.
6. Remove the plugs from the vapor and liquid line stubs.
7. Wrap a wet rag around each TXV before brazing to
avoid overheating the valve.
8. Remove protective coil cover between TXVs and
evaporator coil as illustrated in figure 1.
Page 7
Size/Quantity
Liquid Line
5/8" (1)
5/8" (2)
5/8" (2)
PROTECTIVE COIL COVER BETWEEN TXV(S)
AND EVAPORATOR COIL.
REMOVE TAPES
Vapor/ Suction Line
1−1/8" (1)
7/8 (2)
1−1/8" (2)
TAA SERIES