direct vent or non direct

[harshal]

Most of the for furnaces now can be installed as direct vent or non direct vent.so is it OK to install the high eff furnace of 7000btuh in the 1300 sq ft home as a non direct vent .the house is 30 yrs  old.
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[bster352]

Read the manual to confirm but it should be ok as long as the fresh air piping is there and sized correctly.

[Admin]

(8.1.2) The requirements of 8.2 through 8.5 inclusive do not apply to:
(a) direct-vent appliances, or
(b) Category IV appliances unless installed in designated R-2000 homes or in an enclosure.

If the house is 30 years old and it most likely does not conform to Clause 8.2.1,

(8.2.1) An outdoor air supply sized in accordance with Clause 8.2.2 shall be provided for an enclosure or structure in which an appliance is installed when the enclosure or structure
(a) has a vapor or air barrier with joints continuously sealed by taping or caulking in all thermally insulated walls, ceilings and floors, or
(b) has an equivalent leakage area of 78 in² or less at a differential pressure of 9.00144 psig as determined by a recognized Canadian fan depressurization test procedure.

Your furnace is most likely a Category IV appliance and if the furnace is not installed in an enclosure then no outdoor air supply is required by Code.

Bster352 is right though, you must follow the installation manual if its outdoor air requirements are more stringent than the Gas Code.

If you have other gas appliances like a water heater or dryer you would have to size the outdoor air supply according to Tables 8.1 to 8.4.

You're safer installing an outdoor air supply.  If the client turns on the dryer, range hood, bathroom exhaust fans and the furnace you could be left with a negative air situation.  If there's a natural draft water heater the flue gases could come back down the chimney.  The TSSA would hold you responsible even if the furnace manual and Gas Code did not require an outdoor air supply.