Determining The Total
Square Feet of Heating Surface

Step 1
Determine The Following Variables:
Boiler Water Entering: _______________  ^oF
Boiler Water Leaving:________________^oF
Boiler Water Flow Rate:_____________GPM
Recovery Rating:___________________GPH
Incoming Cold Water:__________________ ^oF
Desired Hot Water:_____________________^oF

Step 2
Determine if the storage tank is to include a built-in Intra-Tank circulator, or if it is to rely on natural convection for circulation within the tank. 

Note: If the Recovery Rating is greater than three times the storage capacity of the vessel, then the heating coil may be wrapped and baffled to allow for an integral pump to force circulate water over the heating coil. The pump must be sized for the maximum GPM recovery rating.

Step 3
Use Chart #3 to determine the conversion factor of GPH heated per square foot of heating coil at the given boiler water entering and leaving temperature, temperature rise, and method of tank circulation.

Step 4
Solve for the required square footage of heating surface by dividing the total GPH recovery by the conversion factor solved for in Chart #3.

Selecting The Steam Coil

Step 5
Determine the length of the heating coil.
Note: A coil in a vertical tank should be as close to but not exceeding the diameter of the vessel as possible.
A coil in a horizontal tank is typically approximately 2/ 3 the length of the vessel
______  " Approximate Coil Length desired

Step 6
From Chart #4 starting with the smallest diameter coil, continue down the Coil Total Sq. Ft. column until the desired Sq. Ft. as determined in Step 4 is within the range. Then multiply the desired Sq. Ft. of heating surface by the length multiplier. This will yield the total length of the coil. If the resulting length is longer than the required length as determined in Step 5, then continue to the next coil range until a suitable length can be selected.

Step 7
Formulate the coil model number by using the model number configurator on the back page.

Temperature

Boiler Water Temperature

180^oF-160^oF

190^oF-170^oF

200^oF-180^oF

212^oF-192^oF

40-120^oF

27

30.4

34.0

39.9

20.3

24.0

27.7

32.3

40-140^oF

18.0

21.0

24

28

13.7

16.5

19.5

23.2

40-160^oF

10.0

13.1

15.4

19.9

8.7

10.7

13.7

16.8

40-180^oF

---

---

10.1

12.9

---

---

9.1

11.9

50-120^oF

28.9

33.2

37.5

43.1

22.1

26.3

30.5

35.6

50-140^oF

19.0

22.2

25.5

29.9

14.4

17.6

20.8

24.7

50-160^oF

11.0

13.5

16.4

21.0

9.0

11.5

14.3

17.6

50-180^oF

---

---

10.3

14.0

---

---

9.3

12.3

60-120^oF

32.1

36.9

41.8

47.9

24.4

29.1

34.3

39.8

60-140^oF

19.9

23.5

27.2

31.9

15.0

18.5

22.3

26.5

60-160^oF

11.1

13.7

16.6

22.2

9.1

11.6

14.4

18.5

60-180^oF

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---

10.3

14.1

---

---

9.3

12.3

Base
Head

Head Flange Size
(150 lb. ASA)

4 Pass

6 Pass

Number
of
Tubes

Coil Total
Sq. Ft.
Range

Length
Multiplier

Steam Inlet And
Condensate Outlet
Port Sizing
Male NPT (Inches)

Steam Inlet And
Condensate Outlet
Port Sizing
Male NPT (Inches)

C

4

1

1

5

1-24

6.3

D

5

1 1/4

1

7

2-31

4.4

E

6

1 1/2

1 1/4

13

4-55

2.4

F

8

2

1 1/2

24

11-105

1.3

G

10

3

2

41

17-186

0.76

H

12

3

2 1/2

59

34-266

0.53

J

14

4

3

92

42-364

0.39

K

16

To Spec

To Spec

112

54-625

0.28

L

18

To Spec

To Spec

143

76-803

0.22