Trane GHND-SVX01A-EN - Manual (Page 31)

GHND-SVX01A-EN • High Efficiency Propeller Fan Gas Unit Heater 31
Operation
GAS INPUT RATE
Check the gas input rate as follows (Refer to general safety section for metric
conversions/SI units):
Note: IMPORTANT! Never overfire the unit heater, as this may cause unsatisfactory
operation or shorten the life of the heater.
1. Turn off all gas appliances that use gas through the same meter as the unit heater.
2. Turn gas on to the unit heater.
3. Clock the time in seconds required to burn one cubic foot of gas by checking the gas
meter.
4. Insert the time required to burn one cubic foot of gas into the following formula and
compute the input rate.
For example, assume the Btu content of one cubic foot of gas equalled 1000 and that it
takes 18 seconds to burn one cubic foot of gas.
Note: If the computation exceeds or is less than 95 percent of the gas Btu/hr. input
rating (see Specifications), adjust the gas pressure.
Gas Pressure Adjustments
Adjust the gas pressure as follows:
1. NATURAL GAS: Optimum results are obtained when the unit heater is operating at
its full input rating with the manifold pressure of 3.5 inches W.C. (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 adjacent to the control outlet.
b. Remove regulator adjustment screw cap, located on combination gas valve.
c. With a small screwdriver, rotate the adjustment screw counterclockwise to
decrease or clock- wise to increase pressure. Do not force beyond stop limits.
d. Replace regulator adjustment screw cap.
2. PROPANE GAS: An exact manifold pressure of 10.0 inches W.C. (2.5 kPa)must be
maintained for proper operation of the unit heater. If the unit is equipped with a
pressure regulator on the combination gas valve, follow steps “a” through “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 vary more than 10% from the pressure
specified in the Main burner orifice schedule table.
3600 (Sec. Per Hr.) x Btu/Cu. Ft = Input Rate
Time (Sec.)
3600 x 1000 = 200,000 Btu/Hr.
18
Gas Input Rate