Schwank supraSchwank - Manual (Page 13)

supra/primo Manual
IM091112
RD: APR 2013
RL: 13B
13
8. VENTILATION
Inadequate venting of a heater may result in asphyxiation, carbon monoxide
poisoning, injury or death. Heating system venting must be in accordance with
all local, state, provincial, and national codes (ANSI Z223.1/NFPA 54 in USA;
B149.1 in Canada).
This heater is approved for unvented (indirect venting) application. Ensure that there is ade-
quate ventilation to supply combustion air and to dilute the products of combustion in accor-
dance with all local, state, provincial, and national codes. A balanced exhaust / inlet air system
is required to ensure that a negative air condition is not created. See below for a summary of
exhaust capacity requirements by the national codes in the U.S.A. and Canada.
Air Supply:
“Loose” buildings may not require any additional air supply if infiltration rates are
sufficient. However, for “tighter” buildings, or if air movement is stagnant in an area, air can
typically be supplied via inlet(s) with an area of 1 sq. in. per 1,000 Btuh input (22 sq cm per
kW). Locate air inlet(s) up at the level of the heaters to avoid cold drafts at work level, and ef-
fectively supply combustion and dilution air to the heaters and balance the system.
Heater Zoning: Exhausters are sized according to the input requirements of each controlled
zone of heaters. Multiple smaller zones are usually more effective in both comfort and ventila-
tion control than one large zone. Maximum zone size is limited by the total input that can be
handled by the capacity of an exhauster, and by the proximity of the exhauster to heaters in the
zone.
Exhauster Location & Proximity: Exhaust must be located as high as practicable in the
structure above the level of the heater(s) to effectively dilute and remove the warm (rising)
products of combustion. The exhauster should be as centrally located as practicable in the
zone of heaters. Schwank recommends a maximum 6:1 ratio of the horizontal distance be-
tween the exhauster and the furthest heater in a zone, to the height the heaters are mounted
above the floor . For example, if heaters are mounted 20 ft above the floor, then the exhaust
fan should be located no more than 120 ft from the furthest heater in the zone. Sufficient air
supply must be provided.
Exhauster Capacity:
USA
: Natural or mechanical means shall be provided to supply and exhaust at least
4ft 3 /min/1000Btuh (0.38m 3 /min/kW) Natural Gas input of installed heaters [4.5ft 3 /
min/1000Btuh (0..43m 3 /min/kW) Propane input]. Some local codes may require an inter-
lock to a dedicated exhaust fan. Consult your local code and ANSI Z223.1 latest edition
for all venting requirements and practices.
Canada
: It is required that the heater(s) be electrically interlocked to dedicated exhaust
fan(s) by means of an Air Proving Switch. Exhaust fan(s) must be sized to create 300
cfm (8.5 cu m/min) exhaust for every 100,000 Btuh (30 kW) or any fraction thereof of
total input of installed equipment. Provide combustion and ventilation air supply com-
patible with exhaust volume . Consult the latest edition of CSA.B149.1 Section 7.22.
WARNING