Schwank supraSchwank - Manual (Page 15)

supra/primo Manual
IM091112
RD: APR 2013
RL: 13B
15
GAS SUPPLY PRESSURE : The maximum supply pressure must be limited to 14 inches w.c.
(0.51 psi). If the line pressure is above 14 inches w.c. then a separate pressure reducing regu-
lator must be used - follow all codes. The minimum pressure at the inlet to the heater regulator
must be equal to or greater than 6.0 inches w.c. for NG and 12 inches w.c. for LP. A sealed
regulator is supplied with the heater which maintains the proper manifold pressure when the
main burner is operating under the following pressures:
LINE PRESSURE ( “ w.c.) MANIFOLD PRESSURE
inches w.c.
AT TAP IN GAS VALVE
MINIMUM MAXIMUM
NATURAL GAS 6.0 14.0 5.0
PROPANE GAS 11.0 14.0 10.0
TABLE 3
10 ELECTRICAL REQUIREMENTS AND THERMOSTAT CONTROL
All electrical installations must meet local codes and the latest edition Electrical Code PART 1
CSA C22.1 in Canada and ANSI/NFPA N0 70 in the U.S.A..
TRANSFORMER SPECIFICATIONS
Single heater
requires 24 Volt, 60 Hz electrical transformer sized at 40 VA.
Multiple heaters
in a zone are powered by a single transformer. The proper transformer is 24
Volt AC, 60 Hz, sized at 40 VA for the first heater plus 20VA for each additional heater in the
zone - round up the calculated value to the next higher available sized transformer. For exam-
ple, four heaters in a zone require a transformer of : 1 x 40VA + 3 x 20 VA = 100 VA . It is not
recommended to install more than 12 heaters per zone.
PROPER WIRING POLARITY MUST BE MAINTAINED, particularly when grouping the heaters
in a zone. Total wiring distances of up to 200' must use minimum 16 gauge electrical wire, and
wiring distances of over 200' must use minimum 14 gauge electrical wire. The heater must be
electrically grounded in accordance with local and national electrical codes. Malfunction of the
heating system will result if the voltage varies by more than +10% or -10%.
The heater can be controlled by a line voltage thermostat, a 24 volt thermostat or “off-on”
switch. Total load of all heaters must be considered in determining the required contact rating
of the controlling thermostat or switch.