Carrier 48KHA - Manual (Page 10)

GAS INPUT
A CAUTION
These units are designed to consume the rated gas
inputs using the fixed orifices at specified manifold
pressures as shown in Table 4. DO NOT REDRILL
ORIFICES UNDER ANY CIRCUMSTANCES.
The rated gas inputs shown in Table 4 are for altitudes from
sea level up to 2000 ft above sea level. These inputs are
based on natureJ gas with a heating value of 1050 Btu/cu ft
at 0.65 specific gravity, or propane gas with a heating value
of 2500 Btu/cu ft at 1.5 specific gravity. For elevations
above 2000 ft, reduce input 4% for each 1000 ft above sea
level. When gas supply being used has a different heating
value or specific gravity, refer to Carrier training manuals,
national and local codes, or contact your Carrier distributor
or dealer to determine required orifice size.
ADJUSTING GAS INPUT-The gas input to unit is deter­
mined by measuring the gas flow at the meter or by measur­
ing the manifold pressure. Measuring the gas flow at the
meter is recommended for natured gas units. Manifold pres­
sure must be measured to determine the input of propane
gas units.
Measuring Gas Flow at Meter Method—Natural Gas
Units—Minor adjustment can be made by changing mani­
fold pressure. Manifold pressure must be maintained
between 3.2 and 3.8 in. wg. If larger adjustments are
required, change main burner orifices following recommen­
dations of national and loced codes.
NOTE: All other appliances that use the same meter must
be turned off when gas flow is measured at meter.
Proceed as follows:
1. Turn off gas supply to unit.
2. Remove pipe plug on bottom of gas vedve, then connect
water manometer at this point. Turn on gas to unit.
3. Record number of seconds for gas meter test dial to
make one revolution.
4. Divide number of seconds in step 3 into 3600 (number
of seconds in one hour).
5. Multiply result of step 4 by the number of cu ft shown
for one revolution of test dial to obtain cu ft of gas flow
per hour.
6. Multiply result of step 5 by Btu heating value of gas to
obtain toted measured input in Btuh. Compare this
value with heating input shown in Table 4. Consult
local gas supplier if the heating value of gas is not
known.
Example: Assume that the size of test dial is one cu ft, one
revolution takes 30 seconds and the heating value of the gas
is 1050 Btu per cu ft, then proceed as follows;
a. 30 seconds to complete one revolution.
b. 30 divided into 3600 equals 120.
c. 120 times one equals 120 cu ft of gas flow per hour.
d. 120 times 1050 equals 126,000 Btuh input.
If the desired gas input is 125,000 Btuh, only a minor
change in the manifold pressure is required.
Observe manifold pressure and proceed as follows to adjust
gas input:
1. Remove cover screw over REG ADJ screw on gas
valve.
2. Turn regulator adjustment screw clockwise to increase
gas input, or turn regulator adjustment screw counter­
clockwise to decrease input. Manifold pressure must be
between 3.2 and 3.8 in. wg. UNSAFE OPERATION
OF THE UNIT MAY RESULT IF MANIFOLD
PRESSURE IS OUTSIDE THIS RANGE.
3. Replace vented seal on gas valve.
4. Turn off gas supply to unit. Remove manometer from
pressure tap. Replace pipe plug on gas valve. Turn on
gas to unit. Check for leaks.
Measuring Manifold Pressure—Propane Gas Units—The
main burner orifices on a propane gas unit are sized for the
unit rated input when manifold pressure is 10.5 in. wg.
Proceed as follows to adjust gas input on propane gas unit:
1. Turn off gas to unit.
Remove pipe plug on gas valve outlet identified as
PRESS. TAP, then connect manometer at this point.
Turn on gas to unit.
4. Remove cover screw over REG ADJ screw on gas
valve.
Adjust regulator adjustment screw for a manifold pres­
sure reading of 10.5 in. wg. Turn adjusting screw clock­
wise to increase manifold pressure, or turn adjusting
screw counterclockwise to decrease manifold pressure.
Replace cover screw.
Turn off gas to unit. Remove manometer from pressure
tap. Replace pipe plug on gas valve, then turn on gas to
unit. Check for leaks.
2
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3.
5.
6 .
7.
Table 4—Rated Gas Inputs at Indicated Manifold Pressures
GAS SUPPLY NATURAL GAS PROPANE GAS
NUMBER PRESSURE (in. wg) PRESSURE Orifice Heating Orifice Heating
MODEL 48- OF Natural Propane (in. wg) Part No. Input Part No. input
ORIFICES Min Max Min Max Natural Propane (Size) (Btuh)* (Size) (Btuh)*
KLA118,124,130 2 5.0 13.6 11.0 13.0 3.5 10.5 LH32DB204(45) 40,000 LH32DB201(55) 40,000t
KLA136,142 3 5.0 13.6 11.0 13.0 3.5 10.5 LH32DB205(45) 60,000 LH32DB201(55) 60,000t
KHA024,030 3 5,0 13.6 11.0 13.0 3.5 10.5 LH32DB207(42) 75,000 LH32DB060(53) 75,000
KLA148 4 5.0 13.6 11.0 13.0 3.5 10.5 LH32DB205(45) 80,000 LH32DB201(55) 80,000t
KHA136,KLA160 5 5.0 13.6 11.0 13.0 3.5 10.5 LH32DB205(45) 100,000 LH32DB201(55) ioo,ooot
KHA036,042,048 5 5.0 13.6 11.0 13.0 3.5 10.5 LH32DB207(42) 125,000 LH32DB060(53) 125,000
KHA060 6 5.0 13.6 11.0 13.0 3.5 10.5 LH32DB207(42) 150,000 LH32DB060(53) 150,000
♦Based on altitudes from sea level up to 2000 ft above sea level. For alti­
tudes above 2000 ft, reduce input rating 4% for each 1000 ft above sea
levei
fWhen KLA is converted to propane, all
See kit instructions
NOx burners must be modified
10