Trane GMND-SVX01B-EN Installation, Operation And Maintenance Manual page 28

Start-Up
Gas Input Rate
NOTICE:
Overfiring!
Never overfire the duct furnace, as this could cause
unsatisfactory operation, or shorten the life of the
heater.
Check the gas input rate as follows:
1. Turn off all gas appliances that utilize gas through the
same gas meter as the unit heater.
2. Turn gas on to the unit heater.
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:
Heating Value (Btu/ft
Input Rate =
Example: If the heating value = 1000 BTU/ft
3 3
ft = 18 s/ft then
(1000 BTU/ft
Input Rate =
Input Rate = 200,000 BTU/hr
(Refer to "General Safety Information, " p. 7
conversions.)
Note: If the computation exceeds, or is less than 95
percent of the gas Btu/h input rating (see
Dimensions and Weights, " p.
pressure:.
Gas Pressure Adjustments
Adjust the gas pressure as follows:
1. NATURAL GAS: Best results are obtained when the
duct furnace is operating at its full input rating with the
manifold pressure of 3.5 inches wc (0.9 kPa).
Adjustment of the pressure regulator is not normally
necessary since it is preset at the factory.
However, field adjustment may be made as follows:
a. Attach manometer at pressure tap plug below the
control outlet.
b. Remove the regulator adjustment screw cap,
located on the combination gas valve.
c. With a small screwdriver, rotate the adjustment
screw clockwise to increase pressure.
d. Replace regulator adjustment screw cap.
2. PROPANE GAS: An exact manifold pressure of
10.0 inches wc (2.5 kPa) must be maintained for proper
operation of the duct furnace. If the unit is equipped
with a pressure regulator on the combination gas
valve, follow Step a through
is not so equipped, the propane gas supply system
28
3
) (3600 s/hr)
3
Time (s/ft )
3
and the time/
3
) (3600 s/hr)
3
18 s/ft
for metric
"Unit
10), adjust the gas
Step d (above). If the unit
pressure must be regulated to attain this manifold
operating pressure.
Table 7. Main burner orifice schedule
Type of Gas Natural
Heating 1075 BTU/ft
Value (40.1 MJ/m
Input in
1000 Manifold
BTU(a) Pressure 3.5" wc (0.9 kPA) 10.5" wc (2.6 kPA)
3
100 ft /hr 96
Orifice Drill 42
3
125 ft /hr 120
Orifice Drill 42
3
150 ft /hr 140
Orifice Drill 42
3
175 ft /hr 163
Orifice Drill 42
3
200 ft /hr 186
Orifice Drill 42
3
225 ft /hr 210
Orifice Drill 42
3
250 ft /hr 233
Orifice Drill 42
3
300 ft /hr 280
Orifice Drill 42
3
350 ft /hr 326
Orifice Drill 42
3
400 ft /hr 372
Orifice Drill 42
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.
(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).
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.
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
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.
(a)
Propane
3 3
2500 BTU/ft
3 3
) (93.1 MJ/m )
No. of
Burner
Orifices
40 4
54
50 5
54
60 6
54
70 7
54
80 8
54
90 9
54
100 10
54
120 12
54
140 14
54
160 16
54
19.
GMND-SVX01B-EN