York DJ150 - Manual (Page 41)

035-19046-002-B-0104
Unitary Products Group 41
3. Measure the time needed for one revolution of the hand
on the smallest dial on the meter. A typical gas meter
has a 1/2 or a 1 cubic foot test dial.
4. Using the number of seconds it takes for one revolution
of the dial, calculate the cubic feet of gas consumed per
hour. (See example below).
5. If necessary, adjust the high pressure regulator as dis-
cussed in the section “Manifold Gas Pressure Adjust-
ment”. Be sure not to over-fire the furnace on Second
stage. If in doubt, it is better to leave the Second stage of
the furnace slightly under-fired. Repeat Steps 1-5.
To determine the rate of gas flow (First Stage)
1. Turn of all other gas appliances connected to the gas
meter.
2. Turn on the furnace and make sure the thermostat is
calling for first stage (60% input) heat.
3. Even when the thermostat is calling for first stage heat,
the unit will light on second stage and will run on Second
stage for 1 minute. Allow this one-minute time period to
expire and be certain the unit is running on first stage.
4. Measure the time needed for one revolution of the hand
on the smallest dial on the meter. A typical gas meter
has a 1/2 or a 1 cubic foot test dial.
5. Using the number of seconds it takes for one revolution
of the dial, calculate the cubic feet of gas consumed per
hour (See example below).
6. If necessary, adjust the low pressure regulator as dis-
cussed in the section “Manifold Gas Pressure Adjust-
ment”. Be sure not to under-fire the furnace on first
stage. If in doubt, it is better to leave the first stage of the
furnace slightly over-fired (greater than 60% input).
Repeat Steps 1-6.
NOTE: To find the Btu input, multiply the number of cubic
feet of gas consumed per hour by the Btu content of
the gas in your particular locality (contact your gas
company for this information as it varies widely from
area to area).
TABLE 27: GAS RATE CUBIC FEET PER HOUR
Seconds
for One
Rev.
Size of Test Dial
1/2 cu. ft. 1 cu. ft.
10 180 360
12 150 300
14 129 257
16 113 225
18 100 200
20 90 180
22 82 164
24 75 150
26 69 138
28 64 129
30 60 120
32 56 113
34 53 106
36 50 100
38 47 95
40 45 90
42 43 86
44 41 82
46 39 78
48 37 75
50 36 72
52 35 69
54 34 67
56 32 64
58 31 62
60 30 60