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470
CHAPTER20
1953 Guide'
Fig. 4. Equivalent Length of Fittings (Concluded)
GROUP 7. REGISTERS (INCLUDING LOSSES IN STACKHEAD AND VELOCITY PRESSURE).
25 EQ. FT.: FL. REC. & BOX
ONLY
Table 4A. Equivalent Length for Registers
Deflection Angle A
Baseboard, High or Low Sidewall' Registers
-Floor Registers with Box only
Eq. Ft. 35
For 2-way deflection registers, add the vertical and horizontal deflection angles together and multiply by 0.7. Select closest angle A in Table 4A. For diffuser type registers see manufactures' catalogs.
settings are used for high sidewall register installations, and the higher settings for baseboard register installations. For most satisfactory results these settings should be as low as is feasible.
.3. A protective high limit control to stop the flow of fuel to the burner independ ently of the thermostat if the air temperatureexceeds 175 F.
4. On oil and gas burner installations, a protective control should be included to cut off the fuel supply if the fire is extinguished, or if there is a failure of the igni tion system. '
. 5. On automatic stoker installations, a control is usually included to operate thestoker regardless of thermostat settings whenever the bonnet temperature indicates . that the fire is dying, or a time interval contactor is used to cause the stoker to run a few minutes out of each hour.
6. A humidistat to regulate the moisture supplied to the rooms, located either in one of the rooms or in the main return dudt near the furnace.
ADJUSTMENT OF SYSTEM FOR CONTINUOUS AIR CIRCULATION
This procedure applies to the adjustment of an automatically-fired forced warm air heating system to provide continuous air circulation, when the control arrangement is of the type where the room thermostat controls the fire, and the blower control (fan switch) controls the blower operation. This procedure as outlined in detail in Manual 6 of the National Warn Air Heating and Air Conditioning Association, is as follows:7
1. Adjust the fuel input in proper relation to the heat loss of the structure.
2. Determine the temperature rise through the furnace.
3. Adjust the air volume to produce a temperature rise through the furnace of about 100 deg.
4. Adjust the fan switch differential to a minimum of about 15 deg.
5. Adjust the fan switch cut-out point as low as practicable.
6. Adjust the room thermostat temperature differential to a minimum which will cause the burner to cycle frequently.
7. Balance the system by adjusting dampers to produce even temperature distri bution between rooms.
3. Set the room thermostat at the desired room temperature.
Forced Warm Air Systems
134 131 129 126 124 122 120 118 116 114 112 110 109 107 106 105 103 102 101 100 99 98 97 15.1 15.7 16.2 16.9 17.3 17.9 18,4 19.0 19.6 20.3 21.1 22.1 22.5 23.6 24.2 24.8 26.0 26.6 27.3 28.0 28.8 29.6 30.5
98 97 96 95 94 93 29.6 30.5 31.5 32.3 33.3 34.6
116 114 112 111 109 108 106 105 103 102 101 100 99 98 97 96 95 94 93 92 91 90 90
19.6 20.3 21.1 21.6 22.5 23.1 24.2 24.8 26.0 26.6 27.3 28.0 28.8| 29.6 30.5 31.5 32.3 33.3 34.6 35.9 37.3 38.6 38.6
240
87
42.7
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11 St-s
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go o t<Oa"S 0^_ 4S-i 2j * | C| H fc
e aa wa
03 < H
126 123 121 119 117 115 113 111 110 108 107 105 104 103 102 101
16.9 17.6 18.1 18.7 19.3 20.0 20.7 21.6 22.1 23.1 23.6 24.8 25.4 26.0 26.6 27.3
| 190
90 90 38.6 38.6
9O4
CO
88 ^
CO
8 883
o
o c5
i
-
o
91
37.3
89
39.9
89
39.9
00 03CO*OA
92 35.9
93
34.6
94
33.3
o
95
32.3
1 120
e
98 97 96
29.6i 30.5 31.5
100
101 100 99 27.31 28. o! 28.8
e
102
26.6
o
QO tO<0
s
o
103
26.0
104
25.4
106
24.2
o
CO
107
23.6
C*
jO o 00
o 00
28
SI
120
18.4
130 128 15.9 16.4 140 137 14.0 14.6
c-oi SO
160 147 143 140 137 134 131 129 127 124 122 120 118 12.6 12.9 13.5 14.0 14.6 15.1 15.7 16.2 16.6 17.3 17.9 18.5 18.4
114 112 110 109 107 106 20.3 21.1 22.1 22.5 23.6 24.2
103 102 101 100
26.0 26.6 27.3 28.0
O '61
811
rzz on J 'K
901
8'frZ
SOI
-091 j
160 166 152 149 145 142 139 136 133 130 128 126 123 121 119 117 115 113 112 110 108 107
11.4 11.8 12.3 12.7 13.2 13.7 14.2 14.8 15.3 15.9 16.4 16.9 17.6 18.1 18.7 19.3 20.0 20.7 21.1 22.1 23.1 23,6
104 103
25.4 26.0
170
10.6 180 175 9.7 10.0
161 157 153 150 146 143 140 137 134 131 128 126 124 122 120 118 116 114 112
11.3 11.7 12.2 12.6 13.1 13.5 14.0 14.6 15.1 15.7 16.4 16.9 17.3 17.9 18.4 19.0 19.6 20.3 21.1
109 107 106
22.5 23.6 24.2
801
991
170 166 161 157 153 150 146 143 140 137 135 131 128 126 124 122 120 118 116 115 113 111 n o
10.5 10.8 11.3 11.7 12.2 12.6 13.1 13.5 14.0 14.6 14.9 15.7 16.4 16.9 17.3 17.9 18.4 19.0 19.6 20.0 20.7 21.6 22.1
V II 901
091 691
200
8.6
* Register delivery volumes in oolumn 1 for zero length of duct.
116
19.6
135 132 129 127 125 122 120
14.9 15.5 16.2 16.6 17.2 17.9 18.4
156 153 149 145 142 139 136 133 130 128 126 124 121 119 117 115 113 1 112 11.8 12.2 12.7 13.2 13.7 14.2 14.7 16.3 15.9 16.4 16.9 17.3 18.1 18.7 19.3 20.0 20.7 21.1
471 38
00
CO Tf
171 167 163 158 154 151 147 144 140
10.4 10.7 111 11.6 12.1 12.4 12.9 13.4 14.0
165 10.9
ct-o
y-4
174 10.1
C4C0
00
CO
00 y*
3^
Y--03 o
CO <HOO
Register temperature, Fahrenheit. (Use upper value in each group). 1Register delivery volume in cubio feet per minute per 1000 Btu. (Use lower value in each group).