Drain Connections - Mitsubishi Electric PAAA18AA1 Installation Manual

12. Drain connections

CAUTION
Over-tightening the drain connections could result in drain pan breakage and failure.
Finger-tighten the drain pan connections plus one or two turns-no more. Make sure to use a sealant for
threaded joints. Use a sealant that is non-hardening, compatible with plastic, and effective in temperatures
up to 250° F.
CAUTION
The drain pan expands or contracts when exposed to changes in temperature and humid-
ity. Do not wrap Teflon tape or apply Teflon paste, pipe dope or other sealant for metal
pipe application to add bulk to the joint. By using such types of sealants, water can leak
out of the drain pan when the drain pan expands or contracts. Such types of sealants also
lubricate the thread resulting in over torquing and breaking the fitting.
The PAA unit contains two sets of 3/4" FPT drain connections. One set of connections is to be used when
mounting the unit vertically and the other is used when mounting horizontally. Each set contains a primary
drain and a secondary or auxiliary drain. The primary drain is the one that is lowest (even with the bottom
of the pan). The secondary drain is at the higher level. They are labeled on the dimensional drawings
described in the "Dimensions" section.
These units operate with a positive pressure at the drain connections, and although a P-trap is not required,
it is recommended to prevent capacity loss. Always follow local codes and standards.
• The trap needs to be installed as close to the unit as possible. Make sure the top of the trap is below the
connection to the drain pan to allow complete drainage of the pan.
• Slope the drain line a minimum of ¼" per foot.
– Do not reduce the pipe size from ¾", this could cause premature blockage in the lines.
– Do not braze near the plastic drain piping.
© 2022 Mitsubishi Electric US, Inc.
PAA-A18, 24, 30, 36, 42AA1/BA1/CA1
64 Specifications are subject to change without notice.