Daikin DM92SN, Service Instructions Manual

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25
SERVICING
1/4
cu/ft
1/2
cu/ft
1
cu/ft
2
cu/ft
5
cu/ft
10 90 180 360 720 1800
11 82 164 327 655 1636
12 75 150 300 600 1500
13 69 138 277 555 1385
14 64 129 257 514 1286
15 60 120 240 480 1200
16 56 113 225 450 1125
17 53 106 212 424 1059
18 50 100 200 400 1000
19 47 95 189 379 947
20 45 90 180 360 900
21 43 86 171 343 857
22 41 82 164 327 818
23 39 78 157 313 783
24 37 75 150 300 750
25 36 72 144 288 720
26 34 69 138 277 692
27 33 67 133 265 667
28 32 64 129 257 643
29 31 62 124 248 621
30 30 60 120 240 600
31 -- -- 116 232 581
32 28 56 113 225 563
33 -- -- 109 218 545
34 26 53 106 212 529
35 -- -- 103 206 514
Size of Test Dial
GAS RATE -- CUBIC FEET PER HOUR
Seconds for
One
Revolution
1/4
cu/ft
1/2
cu/ft
1
cu/ft
2
cu/ft
5
cu/ft
36 25 50 100 200 500
37 -- -- 97 195 486
38 23 47 95 189 474
39 -- -- 92 185 462
40 22 45 90 180 450
41 -- -- -- 176 439
42 21 43 86 172 429
43 -- -- -- 167 419
44 -- 41 82 164 409
45 20 40 80 160 400
46 -- -- 78 157 391
47 19 38 76 153 383
48 -- -- 75 150 375
49 -- -- -- 147 367
50 18 36 72 144 360
51 -- -- -- 141 355
52 -- -- 69 138 346
53 17 34 -- 136 340
54 -- -- 67 133 333
55 -- -- -- 131 327
56 16 32 64 129 321
57 -- -- -- 126 316
58 -- 31 62 124 310
59 -- -- -- 122 305
60 15 30 60 120 300
GAS RATE -- CUBIC FEET PER HOUR
Seconds for
One
Revolution
Size of Test Dial
Combustion Quality
Combustion quality can be affected by several factors.
Major factors are venting and draining.
Venting
The venting system should be planned and installed with
the following in mind:
• Should not be longer than necessary
• Use 45° elbows rather than 90° elbows when possible
• Must not sag or otherwise trap condensate
• Use longest radius fittings possible
• If using 3" venting, make the transition from 2" to 3" as
close as practically possible
• Make sure there is no flue gas recirculation into the
combustion air pipe
Condensate Drainage
Furnace combustion can be affected if a furnace is holding
condensate. Check for proper connections of drain
hoses; make sure furnace condensate trap is clean. Make
sure furnace is not improperly sloped. Make sure air
conditioning coil drain is not interfering with furnace drain.
Other Causes
1. Manifold Gas Pressure must be set, the gas being
used, Natural or L.P., high and low firing rates. If
converted to L.P. gas, check size of all orifices.
2. Remove Draft Inducer, Check the integrity of the
gasket between the inducer and the collector box
cover, any air leak here will have a negative effect
on combustion. Check the orifice hole in the collector
box, it must be free or burrs on both sides.
3. Make sure burners are clean, not out of position and
line up correctly with heat exchanger tubes, including
the heat exchanger orifice plate - this is the plate
which mounts to the front panel of the heat exchanger
between the burners and the heat exchanger tubes,
make sure it is not loose, missing a screw or hanging
down between the burners and heat exchanger
causing flame impingement.
4. Make sure the field installed gas line is not binding
and causing distortion of burner assembly.
5. If the furnace is installed as a one pipe system; make
sure the surrounding area and structure are adequate
to provide combustion air.
6. Make sure there are no cabinet air leakes allowing
supply air to affect combustion.
7. If heat exchanger integrity is uncertain, follow
procedures in Service Bulletin SF-041.