Goodman GMN SERIES Installation & Operating Instructions Manual page 11

PROTECTION FROM FREEZING
The vent pipe must be properly insulated if there is any chance of condensate freezing inside the pipe, particularly when the
pipe passes through an UNCONDITIONED SPACE or is exposed to the exterior. For exterior use, a minimum of 1 inch thick
closed cell foam insulation is recommended. For interior piping, fiber glass with a vapor barrier having "R" value of R-7 or better
may be used.
VENT LENGTH
The maximum recommended vent length is 60 total equivalent feet with each L.R. 90 degree elbow (3 max.) counted as 5
ft. and each 45 degree elbow (6 max.) counted as 2.5 ft. The vent run should be as short as possible with a minimum length
of 5 ft. for vertical run, and 3 ft. for horizontal run. When determining vent length DO NOT count vent terminal or drain trap
assembly. (S.R. elbows are equivilant to 7 1/2 ft.)
SUPPORTING AND PITCHING
All horizontal runs must be supported at least every 3 ft. with straps or hangers. No sags or dips are permitted. Maintain
1/4 inch per foot minimum pitch upward on all horizontal piping from the drain trap to the vent terminal. Horizontal pipe run
from the unit to the trap must be pitched upward a minimum of 1/4 inch per foot of run away from the drain trap assembly
so the condensate will flow into drain trap. Vertical runs must be supported every 6 ft.
JOINING PIPE AND FITTINGS
Clean pipe joint area and fitting socket of all grease, dirt and moisture. Checking pipe and socket for proper fit.
Wipe socket and pipe with cleaner-primer. Apply a generous coat of primer to connecting areas.
DO NOT ALLOW PRIMER TO DRY BEFORE APPLYING CEMENT.
Apply a thin coat of cement in the socket. Quickly apply a heavy coat of cement to the pipe end and insert pipe into fitting.
Hold the pipe in the fitting for 30 seconds.
Wipe all excess cement from the joint and allow 15 minutes before handling.
DO NOT CEMENT VENT PIPE TO VENT BLOWER OUTLET
CAUTION: For proper installation
DO NOT use solvent cement that has become curdled, lumpy or thickened.
DO NOT thin. Observe shelf precautions printed on containers.
For application below 32 degrees F use only low temperature type solvent cement.
WARNING: DANGER OF FIRE OR BODILY INJURY PVC SOLVENT CEMENTS AND PRIMERS ARE HIGHLY FLAM-
MABLE. PROVIDE ADEQUATE VENTILATION. DO NOT ASSEMBLE NEAR HEAT SOURCE OR OPEN FLAME. DO NOT
SMOKE. AVOID SKIN OR EYE CONTACT. OBSERVE ALL CAUTIONS AND WARNING PRINTED ON MATERIAL
CONTAINERS.
CONDENSATE DRAIN
This furnace is designed to remove both sensible and latent heat from the combustion flue gas. As a result, condensed water
vapor is formed in the secondary heat exchanger and drains to the drain trap outside the unit. Use 1/2 inch PVC flex tube.
Install overflow line if routing to floor drain.
If an indoor drain is not readily available, a condensate pump or sump pump must be used. The condensate pump must be
constructed of acid resistant materials. The condensate pump must have an auxiliary safety switch to prevent operation of
DO NOT RUN CONDENSATE DRAIN TO AN OUTDOOR DRAIN
OR WHERE THE POTENTIAL FOR FREEZING CAN OCCUR.
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