Daikin DM80TN, Service Instructions Manual

Page: 27 / 44

SCHEDULED MAINTENANCE
27
CLOCKING A GAS METER
1. Turn off all gas appliances in the home.
2. Turn on the furnace. Ensure the furnace is operating at a 100% firing rate on 2 stage and modulating furnace product.
3. Once heating cycle is at a steady state (typically 15 minutes of operation), use a stopwatch to time how long it takes
the smallest unit of measure dial on the gas meter to make a full revolution. In Table 1, one cubic foot is selected. The
smallest unit of measure will vary depending on the gas meter.
CUBIC
FEET
1 1
One
In this example
we are using the
one cubic foot
dial on the gas
meter
TABLE 1
4. Using Table 2 below, find the number of seconds it took for the dial to make a full revolution. To the right of that num -
ber of seconds and below the Size of Test Dial (selected in step 3 and shown in Table 1) will be the Cubic Feet per
Hour (CFH).
1/4
cu/ft
1/2
cu/ft
1
cu/ft
2
cu/ft
5
cu/ft
1/4
cu/ft
1/2
cu/ft
1
cu/ft
2
cu/ft
5
cu/ft
10 90 180 360 720 1800 36 25 50 100 200 500
11 82 164 327 655 1636 37 -- -- 97 195 486
12 75 150 300 600 1500 38 23 47 95 189 474
13 69 138 277 555 1385 39 -- -- 92 185 462
14 64 129 257 514 1286 40 22 45 90 180 450
15 60 120 240 480 1200 41 -- -- -- 176 439
16 56 113 225 450 1125 42 21 43 86 172 429
17 53 106 212 424 1059 43 -- -- -- 167 419
18 50 100 200 400 1000 44 -- 41 82 164 409
19 47 95 189 379 947 45 20 40 80 160 400
20 45 90 180 360 900 46 -- -- 78 157 391
21 43 86 171 343 857 47 19 38 76 153 383
22 41 82 164 327 818 48 -- -- 75 150 375
23 39 78 157 313 783 49 -- -- -- 147 367
24 37 75 150 300 750 50 18 36 72 144 360
25 36 72 144 288 720 51 -- -- -- 141 355
26 34 69 138 277 692 52 -- -- 69 138 346
27 33 67 133 265 667 53 17 34 -- 136 340
28 32 64 129 257 643 54 -- -- 67 133 333
29 31 62 124 248 621 55 -- -- -- 131 327
30 30 60 120 240 600 56 16 32 64 129 321
31 -- -- 116 232 581 57 -- -- -- 126 316
32 28 56 113 225 563 58 -- 31 62 124 310
33 -- -- 109 218 545 59 -- -- -- 122 305
34 26 53 106 212 529 60 15 30 60 120 300
35 -- -- 103 206 514
GAS RATE -- CUBIC FEET PER HOUR
Seconds for
One
Revolution
Size of Test Dial
Seconds for
One
Revolution
Size of Test Dial
Locate 40 seconds for one
revolu � on in the chart below
Then locate the 1 cu � dial column and select the
corresponding CFH from the 40 seconds for one revolu � on row
TABLE 2