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client will be at the mercy of the inspector’s experience and
training. On the other hand, if the system has been oper-
ated in the cooling mode, in some cases even only for a few
months, usually the evidence is glaring. The condensation
process can age a furnace dramatically.
CondEnSaTE PanS
Cooling coils come in a variety of shapes and sizes. Slant
coils, N-coils, horizontal slab coils and the popular A-coil
style all are used in residential applications. Attached to the
bottom end of these coils or placed under them is a gutter-
like device or shallow pan that collects the condensate pro-
duced during cooling. They are used in both vertical and
horizontal applications and, though somewhat different for
each orientation, the objective of all condensate drain pans is
to thoroughly collect and then direct the condensate water to
a condensate drain.
When you look at a coil box or the air handler’s service panel
installed in front of the coil, you will notice several ¾-inch
pipe openings. Some will be used; some will not. The unused,
sometimes plugged openings likely are for drain connections
to be made when the coil
is used at different orienta-
tions. Many coil boxes and
air handlers can be used in
both vertical and horizontal
applications. By simply re-
positioning the cooling coil
and condensate pan and
then orienting the panel to
fit the correct openings, the
manufacturer can use one
piece of equipment to do many jobs. Inspectors should be
wary of any drain connections made above the two lowest
fittings on the air handler or coil box you’re inspecting. This
could indicate that the installer has made connections to the
wrong fittings. When this is done, the pan can fill to over-
flowing before the water can drain away.
A condensate pan serving cooling coils installed in vertical
applications usually will encapsulate the lower end(s) of the
coil assembly and often obstructs much of actual pan surface
from view, making it difficult to inspect. Condensate pans
used in equipment positioned horizontally usually are more
accessible, simple to service and easy to inspect. The con-
densate pan for vertical installations can be seen under the
“A” coil and is labeled 5 in the image at the bottom on the
opposite page. The condensate pan for a horizontal installa-
tion can be seen at the left side on the air handler and also is
labeled 5.
Today, the major equipment makers use different plastic
materials to build a smooth-surfaced, rust-proof condensate
pan. To assist drainage and prevent pooling, some slope the
base of the pan toward the drain openings. However, since
many of these changes are recent, you’ll still find many of the
older galvanized steel pans under cooling coils.
Inspectors should be aware that the older steel pans have a
much rougher, even pitted, surface that can collect sludge.
Manufacturers relied heavily on installers to tilt this type of
pan in the direction of flow. Failure to do so may have con-
tributed to years of pooling.
Older pans can be more difficult to thoroughly clean and
when there is visible evidence of a little slime in the pan,
there can be much more blocked from view.
A dirty pan can be especially harmful to people with
allergies and weakened immune systems. Breathing the air
circulated across an unclean condensate pan can cause eye
irritations, headaches, sinus issues and serious respiratory
ailments. Although I’m aware that accessing the cooling coil
and the pan can be beyond the scope of a home inspector’s
duties, I would encourage inspectors to notify their clients if
they have not accessed the coil and the pan, and point out the
importance of an annual professional inspection and cleaning.
Unlike the newer plastic pans, which can be cracked or
broken, areas of the steel pans can rust away. When this hap-
pens, water leaking through the pan can be mistaken for an
overflowing blocked drain.
Mistaking a rusted-out pan
for a simple blocked drain
can be costly. Unless you’re
certain of the integrity of
the condensate pan, don’t
call out the evidence of
moisture damage around
the cooling coil as a mere
blocked drain. Replacing
the condensate pan often
requires a total coil replacement and starts at several hundred
dollars. If you are uncertain, note what you observed, recom-
mend further professional evaluation and leave it at that.
TraPPing
Probably the most misunderstood portion of a condensate
drain system is trap installation. The primary purpose of
a condensate trap is to prevent air from moving in or out
of the coil box or air handler during operation. Traps must
be installed in a manner that will stop the air from passing
through, but still allow the condensate to drain from the
condensate pan.
Without a trap, this doesn’t happen. Air that is lost through
the condensate drain in blow-through systems primarily is
an efficiency issue. Failure to install a trap on a blow-through
system can be likened to drilling a hole in the ducts for each
drain connection. As for draining away condensate, the
pressure around the pan on a blow-through system almost
guarantees the pan will drain, trapped or not.
Trapping is a major issue on draw-through systems. Untreated
air can be drawn into the airstream while the system is run-
ning. If the coil is located in an attic or other warm space,
there is even greater reason for concern. As on a
“Unlike the newer plastic pans, which can
be cracked or broken, areas of the steel
pans can rust away. when this happens,
water leaking through the pan can be
mistaken for an overflowing blocked drain.”
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T H E C A N A D I A N
HOME INSPECTOR
CONDENSATE continued from page 19