Carrier 48KHA User Manual
Page 11
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6. Multiply result of step 5 by Btu heating value of
gas to obtain total measured input in Btuh. Com
pare 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 120cuft 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 counterclockwise to decrease input. Mani
fold 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 cap 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.
2. Remove pipe plug on gas valve outlet identified
as PRESS. TAP, then connect manometer at this
point.
3. Turn on gas to unit.
4. Remove cover screw over REG ADJ screw on
gas valve.
5. Adjust regulator adjustment screw for a manifold
pressure reading of 10.5 in. wg. Turn adjusting
screw clockwise to increase manifold pressure, or
turn adjusting screw counterclockwise to de
crease manifold pressure.
6. Replace cover screw.
7. 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.
ADJUSTING BURNER AIR SHUTTERS —
After burners have operated at full input for at least
10 minutes, adjust primary air to each burner to
ensure optimum heating performance. Make these
adjustments when unit is being installed and during
routine maintenance inspections at beginning of
each heating season. Be sure each burner is clean and
free of deposits before adjusting primary air.
Primary air to each burner is regulated by burner
air shutter on each burner. See Fig. 9 (Burner
Flames, Standard) for location of burner air shutter.
With all burners operating, adjust primary air to
each burner as follows:
1. Loosen locking screw that secures air shutter in
place on burner, then partially close air shutter
until a slight yellow tip appears on top of burner
flames.
Table 4 — Rated Gas Inputs at Indicated Manifold Pressures
MODEL 48-
NUMBER
OF
ORIFICES
GAS SUPPLY
PRESSURE (in. wg)
MANIFOLD
PRESSURE
(in. wg)
NATURAL GAS
PROPANE GAS
Orifice
Part No.
(Size)
Heating
Input
(Btuh)*
Orifice
Part No.
(Size)
Heating
Input
(Btuh)*
Natural
Propane
Min
Max
Min
Max
Natural
Propane
KLA118,124,130
2
50
13 6
11 0
13 0
3 5
10 5
LH32DB205(45)
40,000
LH32DB201(55)
40,000
KLA136,142
3
50
13 6
11 0
13 0
3 5
10 5
LH32DB205(45)
60,000
LH32DB201(55)
60,000
KLA036,042
3
50
13 6
11 0
13 0
3 5
10 5
LH32DB205(45)
60,000
LH32DB201(55)
60,000
KHA024,030
3
50
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
LH32DB20K55)
80,000
KLA048
4
50
13.6
11 0
13 0
3 5
10 5
LH32DB205(45)
80,000
LH32DB201(55)
80,000
KHA136.KLA160
S
5.0
13 6
11 0
13 0
3 5
10 5
LH32DB205(45)
100,000
LH32DB201(55)
100,000
KHA036
5
5 0
13 6
11 0
13 0
3 5
10 5
LH32DB205(45)
100,000
LH32DB201(55)
100,000
KHA042
5
50
13 6
11 0
13 0
3 5
10 5
LH32DB207(42)
1 25,000
LH32DB060(53)
125,000
KHA036BF/CF
KHA048BF/CF
5
5.0
13 6
11 0
13 0
3 5
10 5
LH32DB207(42)
1 25,000
LH32DB060(53)
125,000
KHA060BF
6
5 0
13 6
11 0
13 0
3 5
10 5
LH32DB207(42)
1 50,000
LH32DB060(53)
150,000
*Based on altitudes from sea level up to 2000 ft above sea level
For altitudes above 2000 ft, reduce input rating 4% for each
1000 ft above sea level