State Industries GPO 86-199 manual Flue GAS Venting, Vent Connector and Draft Regulator, Chimney

•When communicating with outdoors by means of vertical ducts, each opening shall have a free area of not less than one square inch per 4,000 Btu per hour (551 mm2/kW) (35 square inches per gallon of oil consumed per hour) of total input rating of all appliances in the enclosure.

•If horizontal ducts are used, each opening shall have a free area of not less than one square inch per 2,000 Btu per hour (1,101 mm2/kW) (70 square inches per gallon of oil consumed per hour) of total input of all appliances in the enclosure, fig. 5.

APPLIANCE AERATION FROM OUTDOORS (OPTIONAL

FOR CONVENTIONAL BUILDINGS, MANDATORY

FOR TIGHT BUILDINGS)

FIGURE 5

TABLE 4 SUGGESTED VENT CONNECTOR SIZES

*These models are factory supplied with a flue reducer which should be installed on the top cover.

In venting systems where a continuous or intermittent back (positive) draft is found to exist, the cause must be determined and corrected. In some cases, a special vent cap may be required.

If the back draft cannot be corrected by normal methods or if a suitable draft cannot be obtained, a blower type flue gas exhauster must be employed to assure venting and correct combustion.

Note: A negative draft must be maintained in the vent piping.

Connections shall not be to a chimney, vent or venting system served by a power exhauster unless the connection is made on the negative pressure side of the exhauster.

The barometric draft regulator must be installed in the same room as the heater, fig. 6. Locate the regulator as close as possible to the heater and at least 18" (457.2 mm) from a combustible ceiling or wall. A manually operated damper should not be placed in the chimney connector.

FLUE GAS VENTING

In the absence of any local codes, regulations, or vent pipe or chimney manufacturer's recommendations, for oil fired equipment, follow the suggestions below for designing and installing a venting system.

For these water heaters, it is recommended that an adequate chimney be used for venting the flue gases. Type B, double wall, vent pipe should be used as the vent connector pipe. However, where no chimney is available, vent pipe may be used to construct a vent.

Where an existing chimney or vent is to be used, be sure that the chimney or vent has adequate capacity for the number and sizes of appliances being vented through it. Inspect the chimney or vent and remove all soot or other obstructions which will retard free draft.

PROPER VENT CONNECTOR INSTALLATION

FIGURE 6

The chimney or vent connector diameter should be the same size as the heater flue outlet, see Table 4. A minimum rise of 1/4" per foot (21mm/M) of horizontal connector length must be maintained between the heater and chimney opening, fig. 6. The connector length should be kept as short as possible.

The oil-fired water heater must be connected to a chimney built in accordance with accepted building code practice or listed factory built type, Table 5. The exit point of the chimney flue gas must be at least 3' (0.91 M) above the highest point where it passes through the roof of a building. Also, it must be at least 2' (0.61 M) higher than any portion of a building within 10' (3.05 M) of the chimney.