Leak Check; High Altitude Derate - Nordyne M2RC-080 Installation Instructions Manual

Typical Left Side Entry - Upflow
Burner Viewport
Roll_ut Limit
°Ourn r °'llll
Some Utilities Assembly
Require Shut- I F
_
Off Valve to
be 4 to 5 feet
Above Floor - Ground
/ Denotes field-
Automatic Gas Valve / provided and
(wdh manuel shut-off) installed
component.
Typical Right Side Entry - Downflow
Denotes field-
provided and Automatic
installed Gas Valve
components. (with manual
shut-off)
' Ground J<
, UrlioR
Burner Roll-Out Lim_
Assembly _,
Ii .....
int
Some Utilities
1 Require Shut-
Off Valve to
be 4 to 5 feet
Above Floor
_-Bumer Viewport
Figure 21. Typical Gas Service Connection
NOTE: Gas piping must not be run in or
through air ducts, chimneys, gas vents,
elevator shafts, etc.
water column), the furnace must be discon-
nected from the gas supply piping system to
prevent damage to the gas control valve.
If the test pressure is less than or equal to
1/2 psig (14 in. water column), the furnace must
be isolated from the gas supply line by closing
the manual shut-off valve.
Leak Check
After the gas piping to the furnace is complete,
all connections must be tested for gas leaks.
To check for leaks use only a soap and water
solution or other approved method.
High Altitude Derate
The nameplate input rating for the furnaces
apply for elevations up to 2,000 feet (610m)
above sea level. For elevations over 2,000
feet, reduce the input by 4% for each 1,000 feet
above sea level. For example, a furnace ap-
plied at an elevation of 5,000 feet should be
derated by 20%. See Table 9 describing the
correct orifice for derate.
NOTE: For Canadian high altitude (2,000 to
4,500 ft.), simply reduce the gas manifold
pressure to 2.8" WC for natural gas and 8.5"
WC for LP gas without changing the orifices.
NOTE: The density of air decreases with
increasing elevation above sea level. This
reduces the quantity of combustion air drawn
into the furnace under normal operation and
requires the unit be derated by using smaller
gas orifices or lower manifold pressure.
Compounds used on threaded joints of gas
piping must be resistant to the actions of
liquefied petroleum gases.
The main manual gas valve and main power
disconnect to the furnace must be prop-
erly labeled by the installer in case emer-
gency shutdown is required.
CAUTION:
Do not use matches, lighters, candles,
or other sources of open flame to check
for gas leaks.
NOTE: When pressure testing gas supply
lines at pressures greater than 1/2 psig (14 in.
CAPACITY OF BLACK IRON GAS PIPE (CU, FT, PER HOUR)
FOR NATURAL GAS (SPECIFIC GRAVITY - 0.60)
i_OMI MAL LENGTH OF PIPE RUN
BLACK IRON _feet)
PIPE DIAMETER
(in. I 10 2D 30 40 50 60 70 80
1/2 130 90 75 65 55 50 45 40
3#4 280 190 150 130 115 105 95 90
1 520 350 285 245 215 195 180 170
1 114 1050 730 590 5(0 440 400 370 350
1 1/2 1600 1100 890 7_ 670 610 560 530
T_e cubicfeetperhourlietedinthetableabove mustbegreeterthan
the cubicfeetper hourofgas flowrequiredby thefurnace.
To determine the cubic feet per hour of gas flow required by the
furnace, divide the input rate ofthe furnace bythe heating value ofthe
gas:
Cubic Feet -- InputTo Furnace (Btu/hr)
Per HourRequired HeatingValue ofGas (Btu/Cu, Ft.)
Table 8. Capacity of Black Iron Gas Pipe
(cu. ft. per hour) for Natural Gas
(specific gravity = .60)
2O