A.O. Smith 240 T-H3J Service Manual page 72

12-8. (B) ON/OFF conditions: BTU requirements
A. Calculating the ON/OFF conditions of the water heater
( T – T
set in
"Condition needed to turn the water heater OFF"
( T – T ) × GPM × 500 < 11,900 or T
set in
Where: T = Set temperature and T
set
B. Calculation example
set
(120 – T
in
(120 – T ) × 2.5 × 500 < 11,900
in
C. ON/OFF table
Set temperature
(
ON 40.5
100
OFF 52.4
ON 50.5
110
OFF 62.4
ON 60.5
120
OFF 72.4
ON 70.5
130
OFF 82.4
ON 80.5
140
OFF 92.4
ON 90.5
150
OFF 102.4
ON 100.5
160
OFF 112.4
ON 115.5
175
OFF 127.4
ON 125.5
185
OFF 137.4
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
= T
in set
in
in
T
in
0.5 1.0 1.5
70.2 80.2
76.2 84.1
80.2 90.2
86.2 94.1
90.2 100.2
96.2 104.1
100.2 110.2
106.2 114.1
110.2 120.2
116.2 124.1
120.2 130.2
126.2 134.1
130.2 140.2
136.2 144.1
145.2 155.2
151.2 159.1
155.2 165.2
161.2 169.1
72
Flow rate (GPM)
2.0 2.5 3.0
85.1 88.1 90.1
88.1 90.5 92.1
95.1 98.1 100.1
98.1 100.5 102.1
105.1 108.1 110.1
108.1 110.5 112.1
115.1 118.1 120.1
118.1 120.5 122.1
125.1 128.1 130.1
128.1 130.5 132.1
135.1 138.1 140.1
138.1 140.5 142.1
145.1 148.1 150.1
148.1 150.5 152.1
160.1 163.1 165.1
163.1 165.5 167.1
170.1 173.1 175.1
173.1 175.5 177.1
Page
CONFIDENTIAL
Ver. 1.00
3.5 4.0
91.5 92.6
93.2 94.0
101.5 102.6
103.2 104.0
111.5 112.6
113.2 114.0
121.5 122.6
123.2 124.0
131.5 132.6
133.2 134.0
141.5 142.6
143.2 144.0
151.5 152.6
153.2 154.0
166.5 167.6
168.2 169.0
176.5 177.6
178.2 179.0