QTD2
Series
29
3.0
Installation
•
Installation of the Gas Line to the Heater
Refer to Chart 3.5 for natural gas and Chart 3.6 for propane to determine the cubic feet per hour (CFH)
required for the type of gas and size of unit to be installed. To determine the proper pipe diameter, use the
CFH value and the length of pipe necessary from Chart 3.7. In the case where several units are serviced by
the same main gas line, the total capacity (CFH) and length of main must be adequate to service all
appliances downstream of this main.
Chart 3.5
•
Natural Gas Consumption
* Assumes an average heating value of 1050 BTU/SCF and a Specific Gravity of 0.60.
Chart 3.6
•
Propane Gas Consumption
* Assumes an average heating value of 2500 BTU/SCF and a Specific Gravity of 1.53.
Chart 3.7 allows for a 0.3 inch W.C. pressure drop in the supply pressure from the building main to the inlet
of the unit. Refer to the chart for the appropriate range of inlet pressures for each gas type. When sizing the
inlet gas pipe diameter, make sure that the unit supply pressure can be met after the 0.3 inch W.C. pressure
drop has been subtracted from the main pressure. If the 0.3 inch W.C. pressure drop is too high, refer to
NFPA 54 or the Gas Engineer’s Handbook for other gas pipe capacities.
Model
Input
Manifold Pressure
(Inches W.C.)
Minimum Inlet
Pressure
(Inches W.C.)
Gas Consumption*
(CFH)
QTD2-80N
80,000
3.5
5.0
76.2
QTD2-60N
60,000
3.5
5.0
57.1
Model
Input
Manifold
Pressure
(Inches W.C.)
Minimum Inlet
Pressure
(Inches W.C.)
Gas
Consumption*
(CFH)
Gallons per
Hour*
QTD2-80P
80,000
10.0
11.0
32.0
0.88
QTD2-60P
60,000
10.0
11.0
24.0
0.66