Goodman GSM Installation & Operating Instructions Manual page 10

In addition, the vent temperatures are also considerably lower than conventional furnaces. This allows
the use of low temperature plastic as the vent system. The recommended plastic is schedule 40 PVC,
ABS, DWV (or equivalent if allowed by local code). See the previous chart for proper sizing. The use
o
of two 45 elbows is suggested over the use of a single 90° elbow. The vent pipe must slope toward
the furnace to properly drain the condensate. The drain trap and related parts must be installed as
shown in the illustrations. Failure to follow these instructions can cause products of combustion
including CARBON MONOXIDE entering the dwelling.
IF THIS FURNACE IS INSTALLED IN AN ATTIC OR SIMILAR AREA WHERE CONDENSATE
OVERFLOW MAY BE A PROBLEM, AN AUXILIARY DRAIN PAN MUST BE INSTALLED UNDER
THE FURNACE WITH THE AUXILIARY DRAIN LINES ROUTED TO THE OUTDOORS TO
PREVENT WATER DAMAGE CAUSED BY LEAKS.
THE COMBUSTION PRODUCTS AND MOISTURE IN THE FLUE GASES WILL CONDENSE. THE
CONDENSATE MAY FREEZE ON THE EXTERIOR WALL AND SURROUNDING SURFACES.
SOME DISCOLORATION OR ETCHING IS TO BE EXPECTED.
THE VENT AND COMBUSTION AIR SUPPLY PIPES MUST BE INSPECTED ANNUALLY.
Visually check the vent terminal and combustion air supply pipe screens, clean if necessary.
Visually check for blockage of the condensate disposal system. Hoses may be disconnected to
determine that proper flow is maintained. Should an obstruction be observed, it can be dislodged by
forcing a stream of water through it using a device such as a garden hose.
Materials and procedures must conform to the ASTM Standards.
Pipe and Fittings ASTM 1785, D2465 and D2266
PVC Primer and Solvent Cement ASTM D2564
Procedure for Cementing Joints ASTM D2855 (ref.)
This appliance may be vertically or horizontally vented.
PROTECTION FROM FREEZING The vent pipe and drain assembly must be properly protected
from freezing particularly if it is installed in an UNHEATED SPACE. Low wattage type heaters should
be employed on the drain system. The vent pipe should be insulated using a one (1) inch thick closed
foam insulation if exposed to the outdoors. For pipes located indoors or protected from the elements
such as a garage, basement, etc., fiberglass with an R value of 7 or better is acceptable.
CAUTION
DO NOT install the vent pipe in the same chase with the vent from another fuel burning appliance,
except with a GMN, GMPN, GSM, or GSMS.
DO NOT install the combustion air supply pipe and / or vent pipe under a deck or overhang where
recirculation of combustion products can occur or a positive pressure may exist.
DO NOT install the vent pipe or the combustion air supply pipe within six (6) inches of another fuel
burning appliance.
The drain trap must be easily accessible for checking and / or cleaning. It must be mounted on the
furnace jacket in the holes provided.
DO NOT install the trap higher than the venter blower outlet.
DO NOT install this appliance in any area where freezing may occur without properly protecting the
drain assembly.
CONSULT LOCAL CODES FOR SPECIAL ADDITIONAL REQUIREMENTS.
IO-176 10