Page 6 | LAARS HEATING SYSTEMS |
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2B-1. Combustion Air Supply
1.The heater location must provide sufficient air supply for proper combustion and ventilation of the surrounding area as outlined in the latest edition of ANSI standard Z223.1, and any local codes that may be applicable. Inadequate combustion air supply may result in incomplete combustion, sooting of the heat exchanger, and unsafe operation of the heater.
2.In general, these requirements specify that small heater rooms should be provided with two permanent air supply openings communicating directly through the wall to outside air; one within 12 inches of the ceiling, and the other within 12 inches of the floor. Each opening should have a minimum free area of one square inch per 4,000 BTUH input of the total input rating of all appliances in the enclosed area. See Table 2 for recommended air supply for each model. An improperly ventilated equipment room can get excessively hot and cause accelerated deterioration of controls and electrical components.
IMPORTANT: In beauty shops, barber shops, cleaning establishments and
Heater | Each Opening* |
Model | (Square Inches) |
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500 | 125 |
600 | 150 |
715 | 179 |
850 | 213 |
1010 | 253 |
1200 | 300 |
1430 | 358 |
1670 | 418 |
1825 | 457 |
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*Net Free Area in Square Inches
Area indicated is for one of two openings; one at floor level and one at the ceiling, so the total net free area could be double the figures indicated.
For special conditions refer to the latest edition of ANSI Z223.1.
Consult factory if not communicating directly through the walls with the outdoors.
Note: Check with louver manufacturers for net free area of louvers. Correct for screen resistance to the net free area if a screen is installed. Check all local codes applicable to combustion air.
Table 2. Minimum Recommended
Air Supply to Boiler.
combustion and ventilation air is received from a source outside the building. Please refer to the most recent edition of the National Fuel Gas Code, ANSI Z223.1, or in Canada, CGA requirements.
3.(a) In the United States: Exhaust Fans or Vents: Any equipment which exhausts air from the heater room can deplete the combustion air supply or reverse the natural draft action of the venting system. This could cause flue products to accumulate in the heater room. Additional air must be supplied to compensate for such exhaust. The information in Table 2 is not applicable in installations where exhaust fans or blowers of any type are used. Such installations must be designed by qualified engineers.
(b) In Canada: Follow Canadian standard,
4.If a blower or fan is used to supply air to the heater room, the installer should make sure it does not create drafts which could cause nuisance shutdowns of the pilot. If a blower is necessary to provide adequate combustion air to the heater, a suitable switch or equivalent must be wired into the heater control circuit to prevent the heater from firing unless the blower is operating.
5.The heater must be completely isolated and protected from any source of corrosive chemical fumes such as trichlorethylene, perchlorethylene, chlorine, etc.
2B-2. Venting
1.Laars heaters have
IMPORTANT NOTE: Do not use sheet metal screws at the snap lock joints of Type B gas vents.
2.Do not weld or fasten the vent pipe to the heater draft hood. The weight of the stack must not rest on the heater. The draft hood and heater top must be easily removable for normal heater service and inspection.
3.Avoid using long horizontal runs of the vent pipe, and too many 90° elbows, reductions or restrictions. Horizontal runs should have at least a 1/4" rise per foot in the direction of flow. A vent connector should be supported for the design and weight of the material used to