Specifications

Start-Up
28 GAND-SVX01B-EN
Checking Unit Heater Rate
Gas appliances are rated based on sea level operation,
with no adjustment required at elevations up to 2000 feet
(610 m). At elevations above 2000 feet (610 m), input
ratings should be reduced by 4 percent for each 1000 feet
(305 m) above sea level. Check the input rate as follows:
1. Turn off all other gas appliances that utilize the same
gas meter as the unit heater.
2. Let the unit heater run for 15 minutes.
3. Using the gas meter, clock the time
that it takes to burn
one cubic foot of gas (Heating Value).
4. Insert the time, in seconds
, into the formula below:
Example: If the heating value = 1000 BTU/ft
3
and the time/
ft
3
= 18 s/ft
3
then
Input Rate = 200,000 BTU/hr
(Refer to “General Safety Information,” p. 7 for metric
conversions.)
Primary Air Shutter Adjustment
After the unit has been operating for at least 15 minutes,
adjust the primary air flow to the burners. Turn the friction-
locked, manually-rotated air shutters clockwise to close, or
counterclockwise to open (see Figure 20, p. 27 and
Figure 2, p. 8).
For correct air adjustment, close the air shutter until yellow
tips in the flame appear. Then open the air shutter to the
point just beyond the position where yellow tipping
disappears. Refer to Figure 21.
Note: There may be momentary and spasmodic orange
flashes in the flame. This is caused by the burning
of airborne dust particles, and should not be
confused with the yellow tipping, which is a stable
or permanent situation when there is insufficient
primary air.
NOTICE:
Overfiring!
Never overfire the unit heater, as this could cause
unsatisfactory operation, or shorten the life of the
heater.
Input Rate =
Heating Value (Btu/ft
3
) (3600 s/hr)
Time (s/ft
3
)
Input Rate =
(1000 BTU/ft
3
) (3600 s/hr)
18 s/ft
3
Table 6. Main burner orifice schedule
(a)
(a) This schedule is for units operating at normal altitudes of 2000 feet
(610 m) or less. SPECIAL ORIFICES ARE REQUIRED FOR INSTALLA-
TIONS ABOVE 2,000 FEET (610 m).
Input in
1000
BTU(a)
Type of Gas Natural Propane
No. of
Burner
Orifices
Heating
Value
1075 BTU/ft
3
(40.1 MJ/m
3
)
2500 BTU/ft
3
(93.1 MJ/m
3
)
Manifold
Pressure 3.5” wc (0.9 kPA) 10.5” wc (2.6 kPA)
100 ft
3
/hr 96 40 4
Orifice Drill 42 54
125 ft
3
/hr 120 50 5
Orifice Drill 42 54
150 ft
3
/hr 140 60 6
Orifice Drill 42 54
175 ft
3
/hr 163 70 7
Orifice Drill 42 54
200 ft
3
/hr 186 80 8
Orifice Drill 42 54
225 ft
3
/hr 210 90 9
Orifice Drill 42 54
250 ft
3
/hr 233 100 10
Orifice Drill 42 54
300 ft
3
/hr 280 120 12
Orifice Drill 42 54
350 ft
3
/hr 326 140 14
Orifice Drill 42 54
400 ft
3
/hr 372 160 16
Orifice Drill 42 54
Note: When installed in Canada, any references to deration at altitudes in
excess of 2000 feet (610 m) are to be ignored. At altitudes of 2000
to 4500 feet (610 to 1372 m), the unit heaters must be orificed to
90 percent of the normal altitude rating, and be so marked in
accordance with the CSA certification.