Lennox B050A3B, Инструкция по установке/обслуживанию и руководство для пользователя

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Page 18 of 36 506307-01 Issue 1207
At higher altitudes and varying heating valves, manifold
pressure or orifice changes maybe required. Consult
Tables 6 and 7 for appropriate values. Failure to follow
this warning could lead to a hazardous furnace operating
condition and result in serious bodily injury or loss of life.
WARNING
Determining Furnace Input - Natural Gas ONLY:
NOTE: Burner access panel of furnace must be in place
when checking gs input.
1. Turn OFF all other gas appliances (except for pilot burners)
served by the same gas meter.
2. With furnace operating in full heat cycle, note how many
seconds it takes for one full revolution of the smallest dial
on the meter. Typically, this will be a 1/2 - or - 1 - cubic
foot test dial.
3. Using the number of seconds for one revolution and the
size of the meter dial, determine the cubic foot per hour
of gas flow by using the formula provided below or Table
4.
Cubic Ft/Hr = Number of Dial Revolutions x Cubic Foot/Revolution x 3600
Time (in seconds) Required for Number of Timed Revolutions
4.Calculate the furnace input using the following formula:
BTUH = Cubic Ft/Hr x BTU/Cubic Foot
The local gas supplier should be able to provide the heating
value of the gas, in BTU/cubic foot. If a specific value is not
available, use 1000 BTU/cubic foot for Natural gas or 2500
BTU/cubic foot for Propane (LP).
5. Calculate the unit’s input rate.
Example: If the heating value of the natural gas is
1015 Btu/cu. and it takes 60 seconds to
burn 2 cu. ft. of gas then:
Input = 1015 Btu/cu. ft. x 1 rev x 2 cu. ft./rev. x 3600
60 sec.
Input = 121,8000 btu/hr.
Burner Orifice Sizing:
The furnace is supplied with standard orifices for the
gas shown on the rating plate. Table 5 shows combinations
of heating values and specific gravities for various gases,
from which proper input can be obtained.
If changing orifices is required, remove the manifold from
the furnace (following the instructions found on page 21)
and replace orifices as required by Table 5, the altitude
derating section of this instruction or as local code dictates.
After securing the manifold assembly, replace all other
components and/or wiring, being sure that all connections
and screws are tightened properly.
Altitude Derating:
The following information is provided as guidelines for
altitude derating and is not meant to supersede any state or
local codes. Local codes have priority over any others and
in some case might limit your options in dealing with an
altitude derate situation.
NOTE: In Canada for altitudes up to 4500 ft. (1372 m) see
the rating label on this furnace for proper manifold
pressure and orifice size. Certification for
installations at altitudes over 4500 ft. (1372 m) is
the jurisdiction of local authorities.
Furnace input should be maintained within ± 2% of the
value on the rating plate or appropriate altitude derate.
Adjust manifold pressure or change main orifices size if
required.
WARNING
Burner Orifice Selection
Table 5
Gas Rate (Cubic Feet per Hour)
Table 4