710 / 710 ASME Service Manual
Ver. 1.00
57
CONFIDENTIAL
12-7.(B) ON/OFF conditions: BTU requirements
A. C
alculating the ON/OFF conditions of the 710
【
Condition needed to turn the 710 ON
】
(T
set
– T
in
) × GPM × 500 > 14,880
【
Condition needed to turn the 710 OFF
】
(T
set
– T
in
) × GPM × 500 <11,900 or T
in
= T
set
Where: T
set
= Set temperature and T
in
= Inlet temperature
B. Calculation example
Set temperature: T
set
= 120˚F
Flow rate = 2.5 GPM
【
Condition needed to turn the 710 ON
】
(120 – T
in
) × 2.5 × 500 > 14,880 T
in
< 108.1˚F
【
Condition needed to turn the 710 OFF
】
(120 - T
in
) × 2.5 × 500 < 11,900 T
in
> 110.5˚F
The outlet temperature at that moment will be 120˚F
C. ON/OFF table
Flow rate (GPM)
Set temperature
(˚F)
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
ON
40.5
70.2
80.2
85.1
88.1
90.1
91.5
92.6
100
OFF
52.4
76.2
84.1
88.1
90.5
92.1
93.2
94.1
ON
55.5
85.2
95.2
100.1
103.1
105.1
106.5
107.6
115
OFF
67.4
91.2
99.1
103.1
105.5
107.1
108.2
109.1
ON
60.5
90.2
100.2
105.1
108.1
110.1
111.5
112.6
120
OFF
72.4
96.2
104.1
108.1
110.5
112.1
113.2
114.1
ON
75.5
105.2
115.2
120.1
123.1
125.1
126.5
127.6
135
OFF
87.4
111.2 119.1
123.1
125.5
127.1
128.2
129.1
ON
85.5
115.2
125.2
130.1
133.1
135.1
136.5
137.6
145
OFF
97.4
121.2 129.1
133.1
135.5
137.1
138.2
139.1
ON
95.5
125.2
135.2
140.1
143.1
145.1
146.5
147.6
155
OFF
107.4 131.2 139.1
143.1
145.5
147.1
148.2
149.1
ON
105.5
135.2
145.2
150.1
153.1
155.1
156.5
157.6
165
OFF
117.4
141.2
149.1
153.1
155.5
157.1
158.2
159.1
ON
125.5
155.2
165.2
170.1
173.1
175.1
176.5
177.6
185
OFF
137.4 161.2 169.1
173.1
175.5
177.1
178.2
179.1
