510
Indoor / 510 Outdoor Service Manual
Ver. 1.00
59
CONFIDENTIAL
12-8.(B) Pump control ON/OFF conditions: BTU requirements
A. Calculating the ON/OFF conditions of the pump
【
Condition needed to turn the pump ON
】
( T
set
– T
in
) × GPM × 500 > 18,600
【
Condition needed to turn the pump OFF
】
5 minutes after activation, if the computer detects a BTU requirement of less than 18,600 BTU/h, the
computer will stop the pump 90 seconds.
( T
set
– T
in
) × GPM × 500 < 14,880 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 pump ON
】
( 120 – T
in
) × 2.5 × 500 > 18,600 T
in
< 108.1
˚
F
【
Condition needed to turn the pump OFF
】
( 120 – T
in
) × 2.5 × 500 < 14,880 T
in
> 108.1
˚
F
C.
ON/OFF table
Set temperature
(
˚
F)
Flow rate (GPM)
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
113
ON
38.6
75.8
88.2
94.4
98.1
100.6
102.4
103.7
OFF
53.8
83.4
93.3
98.2
101.2
103.1
104.5
105.6
122
ON
47.6
84.8
97.2
103.4
107.1
109.6
111.4
112.7
OFF
62.8
92.4
102.3
107.2
110.2
112.1
113.5
114.6
131
ON
56.6
93.8
106.2
112.4
116.1
118.6
120.4
121.7
OFF
71.8
101.4
111.3
116.2
119.2
121.1
122.5
123.6
140
ON
65.6
102.8
115.2
121.4
125.1
127.6
129.4
130.7
OFF
80.8
110.4
120.3
125.2
128.2
130.1
131.5
132.6
158
ON
83.6
120.8
133.2
139.4
143.1
145.6
147.4
148.7
OFF
98.8
128.4
138.3
143.2
146.2
148.1
149.5
150.6
167
ON
92.6
129.8
142.2
148.4
152.1
154.6
156.4
157.7
OFF
107.8
137.4
147.3
152.2
155.2
157.1
158.5
159.6
185
ON
110.6
147.8
160.2
166.4
170.1
172.6
174.4
175.7
OFF
125.8
155.4
165.3
170.2
173.2
175.1
176.5
177.6
