72
Page
240 (T-H3J), 340 (T-H3S) and 540 (T-H3) models Service Manial
Ver. 1.00
CONFIDENTIAL
12-8. (B) ON/OFF conditions: BTU requirements
A. Calculating the ON/OFF conditions of the water heater
പ
ഩΗŽŶĚŝƚŝŽŶŶĞĞĚĞĚƚŽƚƵƌŶƚŚĞǁĂƚĞƌŚĞĂƚĞƌKEΗ
( T
set
– T
in
Ϳп'WDпϱϬϬхϭϰ͕ϴϴϬ
"Condition needed to turn the water heater OFF"
( T
set
– T
in
) × GPM × 500 < 11,900 or T
in
= T
set
Where: T
set
= Set temperature and T
in
с/ŶůĞƚƚĞŵƉĞƌĂƚƵƌĞ
B. Calculation example
പഩ^ĞƚƚĞŵƉĞƌĂƚƵƌĞ͗d
set
сϭϮϬȗ&&ůŽǁƌĂƚĞсϮ͘ϱ'WD
പഩΗŽŶĚŝƚŝŽŶŶĞĞĚĞĚƚŽƚƵƌŶƚŚĞǁĂƚĞƌŚĞĂƚĞƌKEΗ
(120 – T
in
ͿпϮ͘ϱпϱϬϬхϭϰ͕ϴϴϬd
in
фϭϬϴ͘ϭȗ&
പഩΗŽŶĚŝƚŝŽŶŶĞĞĚĞĚƚŽƚƵƌŶƚŚĞǁĂƚĞƌŚĞĂƚĞƌK&&Η
(120 – T
in
) × 2.5 × 500 < 11,900 T
in
хϭϭϬ͘ϱȗ&
dŚĞŽƵƚƉƵƚƚĞŵƉĞƌĂƚƵƌĞĂƚƚŚĂƚŵŽŵĞŶƚǁŝůůďĞϭϮϬȗ&
C. ON/OFF table
Set temperature
(
ȗ&Ϳ
Flow rate (GPM)
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
100
ON
40.5
70.2
80.2
85.1
88.1
90.1
91.5
92.6
OFF
52.4
76.2
84.1
88.1
90.5
92.1
93.2
94.0
110
ON
50.5
80.2
90.2
95.1
98.1
100.1
101.5
102.6
OFF
62.4
86.2
94.1
98.1
100.5
102.1
103.2
104.0
120
ON
60.5
90.2
100.2
105.1
108.1
110.1
111.5
112.6
OFF
72.4
96.2
104.1
108.1
110.5
112.1
113.2
114.0
130
ON
70.5
100.2
110.2
115.1
118.1
120.1
121.5
122.6
OFF
82.4
106.2
114.1
118.1
120.5
122.1
123.2
124.0
140
ON
80.5
110.2
120.2
125.1
128.1
130.1
131.5
132.6
OFF
92.4
116.2
124.1
128.1
130.5
132.1
133.2
134.0
150
ON
90.5
120.2
130.2
135.1
138.1
140.1
141.5
142.6
OFF
102.4
126.2
134.1
138.1
140.5
142.1
143.2
144.0
160
ON
100.5
130.2
140.2
145.1
148.1
150.1
151.5
152.6
OFF
112.4
136.2
144.1
148.1
150.5
152.1
153.2
154.0
175
ON
115.5
145.2
155.2
160.1
163.1
165.1
166.5
167.6
OFF
127.4
151.2
159.1
163.1
165.5
167.1
168.2
169.0
185
ON
125.5
155.2
165.2
170.1
173.1
175.1
176.5
177.6
OFF
137.4
161.2
169.1
173.1
175.5
177.1
178.2
179.0
