Honeywell PGF3 - Manual (Page 6)

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3/17/06
FIRE AND/OR EXPLOSION HAZARD
Failure to follow this warning could result in personal
injury, death, and/or property damage.
Do NOT attempt to light the burner with a match or
flame of any kind.
!
HEATING INPUT RATE CHECK
The gas input to the unit is determined by measuring
the gas flow at the meter. Measuring gas flow at the
meter is recommended for natural gas units. To
measure the heating input, perform the following
steps:
1. Turn off all other gas appliances that use the same
meter.
2. Turn off gas supply to unit and attach manifold
pressure gauge as instructed in the ”Gas Valve
Adjustment” section.
3. With gas ON to the unit and the unit operating, record
the number of seconds for the gas meter dial to make
one revolution.
4. Divide number of seconds in Step 3 into 3600
(number of seconds in 1 hour).
5. Multiply result of Step 4 by the number of cubic feet
shown for one revolution of the meter dial to obtain the
cubic feet of gas flow per hour.
6. Multiply result of Step 5 by Btu heating value of gas to
obtain total measured input in Btu/hr. Compare this
input rate with the Required Input Rate for the
installation altitude, as shown in Table 3. Consult with
local gas supplier if the heating value of gas is not
known.
Example: Assume that the size of the meter dial is 1 cu. ft.,
one revolution takes 44 seconds, and the heating value of
the gas is 1020 Btu/ft3. Proceed as follows:
1. 38 sec. To complete 1 revolution
2. 3600/38 = 94.7
3. 94.7 x 1 = 94.7
4. 94.7 x 1020 = 96,632 Btu/hr
For this example, the nameplate input is 100,000 Btu/hr, so
only a minor change in manifold pressure is required. In no
case should the final manifold pressure vary more than
+-- .3 ”water column from the values in Table 2. Never
exceed the required input rate (Table 3).
Table 3
0-2000 2001-3000 3001-4000 4001-5000 5001-6000 6001-7000 7001-8000 8001-9000 9001-10000
"040" or "B" 40,000 35200 33600 32000 30400 28800 27200 25600 24000
"060" or "C" 60,000 52800 50400 48000 45600 43200 40800 38400 36000
"080" or "D" 80,000 70400 67200 64000 60800 57600 54400 51200 48000
"100" or "E" 100,000 88000 84000 80000 76000 72000 68000 64000 60000
"120" or "F" 120,000 105600 100800 96000 91200 86400 81600 76800 72000
"140" or "G" 140,000 123200 117600 112000 106400 100800 95200 89600 84000
1 Note:
For PGF3, PGX3, and PDX3 models, heating model size is indicated by the numbers in the 5 th , 6 th , and 7 th characters in the model number.
For PGF, PGC, PGS models, heating model size is indicated by the numbers in the 8 th , 9 th , and 10 th characters in the model number.
For GPFM, GPCM, and GPSM models, heating model size is indicated by the numbers in the 8 th , 9 th , and 10 th characters in the model number.
For PGAA, PGAD, PGCA, and PGCD models, heating model size is indicated by the letter in the 7 th character in the model number.
For PGMD and PGME models, heating model size is indicated by the letter in the 7 th character in the model number.
Required Input Rate of Furnace Converted to Natural Gas (Btu/hr)
Elevation Above Sea Level (feet)
Required Input Rate for All Models
Heating Model
Size 1