RT-SVX36G-EN 59
Installation
Notes:
1. If more than one unit is served by the same main gas supply, consider the total gas input (cubic feet/hr.) and the total
length when determining the appropriate gas pipe size.
2. Obtain the Specific Gravity and BTU/Cu.Ft. from the gas company.
3. The following example demonstrates the considerations necessary when determining the actual pipe size.
Example: A 40' pipe run is needed to connect a unit with a 500 MBH furnace to a natural gas supply having a rating of 1,000 BTU/Cu.Ft.
and a specific gravity of 0.60
Cu.Ft/Hour = Furnace MBH Input
Gas BTU/Cu.Ft. X Multiplier (Ta bl e 17 )
Cu.Ft/Hour = 500
4. Table 16 indicates that a 1-1/4” pipe is required.
Table 18. Modulating Gas Heat Settings
Natural Gas
Heater Size (MBH) Gas Orifice
Full Modulation Partial Modulation Valve Actuator
Air Damper
Actuator Voltage
Range (VDC)
Air Damper
Actuator Voltage
Range (VDC)
Left (Coarse)
Setting
Right (Fine)
Setting
500 #21 7 - 10 7 - 9.7 2.3 -1
850 #H 6 - 10 6 - 8.7 1.3 -1
1000 #N 5 - 10 5 - 8.7 0.9 0
LP
Heater Size (MBH) Gas Orifice
Full Modulation Partial Modulation Valve Actuator
Air Damper
Actuator Voltage
Range (VDC)
Air Damper
Actuator Voltage
Range (VDC)
Left (Coarse)
Setting
Right (Fine)
Setting
500 #34 / #53 7 - 10 7 - 9.7 6 1
850 #32 6 - 10 6 - 8.7 3.2 1
1000 #29 5 - 10 5 - 8.7 1.9 0
Note: Valve actuator settings are approximate and may require “fine tuning” to properly set. Right (fine) settings given are in notches from the “zero”
midpoint location on sight gage.
Table 19. Gas Heating Capacity Altitude Correction Factors
Altitude (Ft.)
Sea Level - 2000 2001 - 2500 2501 - 3500 3501 - 4500 4501 - 5500 5501 - 6500 6501 - 7500
Capacity
Multiplier
1.00 .92 .88 .84 .80 .76 .72
Note: Correction factors are per AGA Std. 221.30 - 1964, Part VI, 6.12. Local codes may supersede.
Figure 24. Unit Gas Trains (Natural Gas) 235 and 350 MBH