Installation and Maintenance Manual

Start-Up
GTND-SVX01B-EN 41
b. Remove the regulator adjustment screw cap,
located on the combination gas valve.
c. With a small screwdriver, rotate the adjustment
screw counterclockwise to decrease or 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
op
eration of the heater. If the unit is equipped with a
pressure regulator on the combination gas valve,
follow Step a through Step d (above). If the unit is not
so equipped, the propane gas supply
system pressure
must be regulated to attain this manifold operating
pressure.
3. The adjusted manifold pressure should not var
y more
than 10 percent from the pressure specified in Ta b le 9,
p. 41 and Ta b l e 10, p. 42.
Tubular Unit Heater High Altitude Deration
This tubular unit heater has been manufactured utilizing
standard burner orifices and a normal manifold pressure
setting as per the specifications shown on the unit rating
plate (see Table 4, p. 23, Table 9, p. 41, and Table 10, p. 42).
All unit deration must be done through field adjustments
by a qualified technician (see Tab le 10 , p . 4 2). Once the
proper adjustments are made in the field, attach label
#J17-06459 to the unit, and record adjusted manifold
pressure, altitude of the unit installation and the
technician’s name and date on the label using a permanent
marker.
Table 9. All unit sizes: 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” wc (2.5 kPA)
30 ft
3
/hr 28 12 1
Orifice Drill 38 52
45 ft
3
/hr 42 18 1
Orifice Drill 31 48
60 ft
3
/hr 56 24 1
Orifice Drill 27 43
75 ft
3
/hr 70 30 1
Orifice Drill 20 40
90 ft
3
/hr 84 36 1
Orifice Drill 16 36
105 ft
3
/hr 98 42 1
Orifice Drill 11 32
120 ft
3
/hr 112 48 1
Orifice Drill 6 3.1 mm
150 ft
3
/hr 140 60 6
Orifice Drill 42 53
175 ft
3
/hr 163 70 7
Orifice Drill 42 53
200 ft
3
/hr 186 80 8
Orifice Drill 42 53
250 ft
3
/hr 233 100 10
Orifice Drill 42 53
300 ft
3
/hr 280 120 12
Orifice Drill 42 53
350 ft
3
/hr 326 140 14
Orifice Drill 42 53
400 ft
3
/hr 372 160 16
Orifice Drill 42 53
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 ETL certification.