4
18-AD32D1-4E-EN
Installer’s Guide
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.
1. Remove both rubber plugs from the indoor coil.
2. Field supplied tubing should be cut square, round and free of burrs
at the connecting end. Clean the tubing to prevent contaminants
from entering the system.
3. Run the refrigerant tubing into the stub tube sockets of the
indoor unit coil.
PAINTED AREAS OF THE UNIT MUST BE SHIELDED DURING
BRAZING.
4. Flow a small amount of nitrogen through the tubing while brazing.
5. Use good brazing technique to make leakproof joints.
6. Minimize the use of sharp 90 degree bends.
7. Insulate the suction line and its fittings.
8. Do NOT allow un-insulated lines to come into contact with each
other.
When replacing the bulb and hose clamp, the clamp should
be "snug" but not "tight" - spec is to torque the hose clamp
to 20+/-5in-lb.
9. Wrap the TXV with insulation after the hose clamp has been
installed.
H. LEAK CHECK
1. Using a manifold gauge, connect an external supply of dry
nitrogen to the gauge port on the liquid line.
2. Pressurize the connecting lines and indoor coil to 150 PSIG
maximum.
3. Leak check brazed line connections using soap bubbles. Repair
leaks (if any) after relieving pressure.
4. Evacuate and charge the system per the instructions packaged
with the outdoor unit.
I. CONDENSATE DRAIN PIPING
Condensate drain connections are located in the drain pan at the
bottom of the coil/enclosure assembly. The female threaded fit-
ting protrudes outside of the enclosure for external connection. A
field fabricated trap is not required for proper drainage due to the
Figure 7
Figure 8
J. CLEANING THE COIL
The two piece door (3-piece on 24.5" wide models) allows removal
of the outer casing doors without interference from refrigerant or
condensate lines. Once the outer doors are removed the split
inner coil panels can be easily removed. The inside and outside
of the coil can be easily cleaned with a brush and vacuum with
the panels removed. See Figure 7.
The foil covered insulation on 4PXC coils should be wiped down
and residual dirt and dust should be vacuumed up to maintain
good air quality. See Figure 8.
Figure 6
Capillary tubes will come
out the top of bulb when
positioned correctly.
positive pressure of the furnace; however, it is recommended to
prevent efficiency loss of conditioned air.
1. The drain hole in the drain pan must be cleared of all insulation.
2. Insulate the primary drain line to prevent sweating where dew
point temperatures may be met. (Optional depending on climate
and application needs)
3. Connect the secondary drain line to a separate drain line (no
trap is needed in this line).
