17
Condensate Drain Trap
This furnace removes both sensible and latent heat from the
products of combustion. Removal of the latent heat results in
condensation of the water vapor. The condensate is removed from
the furnace through the drains in the plastic transition and the
vent fitting. The drains connect to the externally mounted
condensate drain trap on the left or right side of the furnace.
The start--up of a new furnace will involve a cycle or two of the
furnace to properly prime the condensate trap with water. Until
the trap is fully primed, some condensate will be pulled into the
combustion blower. The furnace may cycle on the pressure switch
connected to the plastic transition box due to condensate buildup.
After the trap is primed, the condensate will start draining from
the furnace. The combustion blower will clear out any remaining
condensate in the blower housing through the vent fitting
downstream of the blower. Note that the condensate trap can also
be primed by pouring water into the
1
/
2
″
drain hose. Remove
the
1
/
2
″
ID drain hose from either the gutter or the white PVC tee
trap. Using a funnel pour eight (8) ounces of water into
1
/
2
″
(13
mm) ID drain hose. Water will flow through the drain hose and
into the condensate drain trap. This will prime both the vent and
the transition sides of the trap. Reconnect the
1
/
2
″
(13 mm) ID
drain hose to the original component, either the gutter or the PVC
tee trap.
The condensate drain trap supplied with the furnace MUST be
used. The drain connection on the condensate drain trap is sized
for
3
/
4
″
PVC or CPVC pipe, however alternate
1
/
2
″
(13 mm)
CPVC (nominal
5
/
8
″
O.D.) or vinyl tubing with a minimum inner
diameter (I.D.) of
5
/
8
″
may also be used, as allowed by local
codes. Alternate drain pipes and hoses may be used as allowed by
local codes.
The drain line must maintain a
1
/
4
″
(6 mm) per foot downward
slope toward the drain.
1
/
4
″
(6 mm) per foot is recommended.
Installation of an overflow line is recommended when the
1
/
4
″
(6
mm) per foot slope to the condensate drain cannot be maintained.
A drain tube clip is included in the furnace to prevent
kinking/buckling of the drain tube. The clip should remain in the
furnace (between the door switch plate and the blower shelf, Fig.
9) during operation. See Fig. 19 for proper routing and
installation of the overflow.
DO NOT trap the drain line in any other location than at the
condensate drain trap supplied with the furnace.
FROZEN AND BURST WATER PIPE HAZARD
Failure to follow this caution may result in property damage.
If a condensate pump is installed, a plugged condensate drain
or a failed pump may cause the furnace to shut down. Do
not leave the home unattended during freezing weather
without turning off water supply and draining water pipes or
otherwise protecting against the risk of frozen pipes.
CAUTION
!
If possible, DO NOT route the drain line where it may freeze.
The drain line must terminate at an inside drain to prevent
freezing of the condensate and possible property damage.
1. A condensate sump pump
MUST
be used if required by
local codes, or if no indoor floor drain is available. The
condensate pump must be approved for use with acidic
condensate.
2. A plugged condensate drain line or a failed condensate
pump will allow condensate to spill. If the furnace is in-
stalled where a condensate spill could cause damage, it is
recommended that an auxiliary safety switch be installed
to prevent operation of the equipment in the event of pump
failure or plugged drain line. If used, an auxiliary safety
switch should be installed in the R circuit (low voltage)
ONLY
.
3. If the auxiliary switch in the condensate pump is used, the
furnace may shut down due to a blocked condensate line
or failed pump. To prevent frozen water pipes see the
“Frozen Water Pipe Hazard” Installation Section of this
manual.
Drain Tube
Clip
Door
Switch
Blower
Shelf
Representative drawing only, some models may vary in appearance.
A07705
Fig. 9 -- Drain Tube Clip Location
Condensate Drain Trap Freeze Protection
Special precautions
MUST
be made if installing furnace in an
area which may drop below freezing. This can cause improper
operation or damage to the equipment. If the the furnace
environment has the potential of freezing, the drain trap and drain
line must be protected. Use 3 to 6 watt per foot at 115 volt, 40
°
F
(4
°
C) self--regulating shielded and waterproof heat tape. Wrap
the drain trap and drain line with the heat tape and secure with the
ties. Follow the heat tape manufacturer’s recommendations.
359AA
V
