RT-SVD03L-EN
121
voltage and the unit Max-Fire voltage. The Modulating
Gas Heat Output Operating Range is determined by the
Supply Airflow measurement.
To keep the heat exchangers from getting too hot or
cold, the supply fan airflow is calculated by measuring
the differential pressure between the fresh air section
and a peizo-electric ring (the transducer is a 0”-5” iwc
Kavlico transducer) on the supply fan discharge orifice.
The resulting airflow will then be standardized to get
CFM/Ton and used to determine the Modulating Gas
Heat Output Operating Range for the valve operation
according to the following table.
Table 88.
Precedent 6 to 10 tons — modulating gas
heat operating range
Airflow
(CFM/
T):
Min
Valve
Pos %
Max
Valve
Pos %
Min
Valve
Com-
mand
%
Max
Valve
Com-
mand
%
Min
Fire
Voltage
Max
Fire
Voltage
175
40
68
0
47
2
5.76
200
40
70
0
49
2
5.92
225
40
71
0
52
2
6.16
250
40
73
0
55
2
6.4
275
40
75
0
58
2
6.64
300
40
77
0
61
2
6.88
Table 88.
Precedent 6 to 10 tons — modulating gas
heat operating range (continued)
Airflow
(CFM/
T):
Min
Valve
Pos %
Max
Valve
Pos %
Min
Valve
Com-
mand
%
Max
Valve
Com-
mand
%
Min
Fire
Voltage
Max
Fire
Voltage
325
40
78
0
64
2
7.12
350
42
80
3
66
2.24
7.28
375
45
82
8
69
2.64
7.52
400
48
83
14
72
3.12
7.76
425
51
85
19
75
3.52
8
450
55
87
24
78
3.92
8.24
475
58
89
29
81
4.32
8.48
500
61
90
35
84
4.8
8.72
525
64
92
40
86
5.2
8.88
550
67
94
45
89
5.6
9.12
575
70
96
51
92
6.08
9.36
600
73
97
56
95
6.48
9.6
625
77
99
61
98
6.88
9.84
650
80
100
66
100
7.28
10
675
83
100
72
100
7.76
10
700
86
100
77
100
8.16
10
725
89
100
82
100
8.56
10
750
92
100
87
100
8.96
10
775
96
100
93
100
9.44
10
800
99
100
98
100
9.84
10
825
100
100
100
100
10
10
Summary of Contents for ReliaTel
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