18-AD25D1-4C-EN
3
Installer’s Guide
Since coil/ enclosure assembly must be installed within
the horizontal run of duct, a transition duct must be
fabricated to mate with the furnace supply outlet duct
flange on one end and the duct flange connection on the
coil/ enclosure assembly on the other end.
For maximum performance, it is recommended that the
transition duct be at least 2 feet in length.
1. Secure the transition duct to the furnace with the
furnace in position.
2. The refrigerant lines and condensate connections of
cased coils may be on either side of the supply air
duct. The air may be directed through the coil from
either side of the coil.
3. Attach the coil/ enclosure assembly to the transition
from the furnace, providing proper support for coil/
enclosure assembly’s weight. Keep the coil level.
Extra pitch is not required for coil to drain properly.
4. Secure the downstream side of coil/ enclosure
assembly to the supply air duct.
NOTE:
Secure properly so there will be no air leakage.
5. The indoor coil must be evacuated through the
refrigerant lines at the outdoor unit before opening
the service valves. See evacuation procedure in Field
Fabricated Refrigerant Lines section of the Installer’s
Guide for the outdoor unit.
6. Complete the installation of the unit per installation
instructions.
E. INSTALLING/BRAZING REFRIGERANT
LINES
CAUTION
!
Do NOT open refrigerant valve at the outdoor unit
until the refrigerant lines and coil have been brazed,
evacuated, and leak checked. This would cause
contamination of the refrigerant or possible discharge
of refrigerant to the atmosphere.
FLUE
STACK
TRANSITION DUCT
COIL/ENCLOSURE ASSY
SUPPLY DUCT
VERTICAL UPFLOW
FURNACE
②
③
1. The following steps are to be considered when
installing the refrigerant lines:
a. Determine the most practical way to run the lines.
b. Consider types of bends to be made and space
limitations.
c. Route the tubing making all required bends and
properly secure the tubing before making final
connections.
NOTE:
Refrigerant lines must be isolated from the structure and
the holes must be sealed weather tight after installation.
IMPORTANT:
Do not unseal refrigerant tubing until ready to fit
refrigerant lines.
There is only a holding charge of dry air in the indoor coil,
therefore no loss of operating refrigerant charge occurs
when the sealing plugs are removed.
NOTE:
TXV bulb MUST be protected (wrapped with wet rag)
or removed, while brazing the tubing. Overheating
of the sensing bulb will affect the functional
characteristics and performance of the comfort coil.
