Adjustment Of Temperature Rise; Checking Gas Input; Secure Owner's Approval; Gas Rate - Cubic Feet Per Hour - York D3CG090 Installation Instructions Manual

530.18-N10Y
After readings have been obtained, remove the tubes and seal
up the drilled holes in the side panels. 5/16" dot plugs (P/N
029-13880) are available through normal parts ordering
procedures.
NOTE: DE-ENERGIZE THE COMPRESSORS BEFORE TAKING ANY TEST
MEASUREMENTS TO ASSURE A DRY INDOOR COIL.
Btuh Input x 0.8
CFM =
1.08 x

ADJUSTMENT OF TEMPERATURE RISE

The temperature rise (or temperature difference between the
return air and the heated air from the furnace) must lie within
the range shown on the U.L. or CGA rating plate and the data
in Table 2.
After the temperature rise has been determined, the cfm can
be calculated as follows:
After about 20 minutes of operation, determine the furnace
temperature rise. Take readings of both the return air and the
heated air in the ducts (about six feet from the furnace) where
they will not be affected by radiant heat. Increase the blower
cfm to decrease the temperature rise; decrease the blower cfm
to increase the rise. Refer to Table 8 for blower motor and drive
data.

CHECKING GAS INPUT

NATURAL GAS
1. Turn off all other gas appliances connected to the gas meter.
2. With the furnace turned on, measure the time needed for
one revolution of the hand on the smallest dial on the meter.
A typical gas meter usually has a 1/2 or a 1 cubic foot test
dial.
3. Using the number of seconds for each revolution and the
size of the test dial increment, find the cubic feet of gas
consumed per hour from Table 12.

SECURE OWNER'S APPROVAL

location of all disconnect switches and the thermostat. Teach him how to start and stop the unit and how to adjust temperature
settings within the limitations of the system.
16
o
F Temp. Rise
: When the system is functioning properly, secure the owner's approval. Show him the
TABLE 12 - GAS RATE - CUBIC FEET PER HOUR
Seconds
for One
1/2 cu. ft.
Rev.
10
12
14
16
18
20
22
24
26
28
30
32
34
36
38
40
42
44
46
48
50
52
54
56
58
60
Example: By actual measurement, it takes 19 seconds for the hand on the 1-cubic
foot dial to make a revolution with just a 100,000 Btuh furnace running. Using this
information, interpolate for 19 seconds in the first column in the table above. Read
across to the column headed "1 Cubic Foot", where you will see that 190 cubic
feet of gas per hour are consumed by the furnace at that rate. Multiply 190 x 1050
(the Btu rating of the gas obtained from the local gas company). The result is
199,500 Btuh, which is close to the 204,000 Btuh rating of the furnace.
If the actual input is not within 5% of the furnace rating (with
allowance being made for the permissible range of the
regulator setting), replace the orifice spuds with spuds of the
proper size.
Size of Test Dial
1 cu. ft.
180 360
150 300
129 257
113 225
100 200
90 180
82 164
75 150
69 138
64 129
60 120
56 113
53 106
50 100
47 95
45 90
86
43
41 82
39 78
37 75
36 72
35 69
34 67
32 64
31 62
30 60
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