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Contractor > Proper Tank Sizing > Thermal Systems

Online Tank Sizing

To properly size your Flexcon thermal tank you will need to obtain the following information:

The total system water content including the water heater and all piping

The initial fill temperature of the system

The maximum water temperature of the system

The normal system water pressure in PSI

The maximum system pressure in PSI (use 10% less than relief valve setting)

 

Once these factors are known, the following calculations will determine, in most cases, the correct model to meet your specifications.*


Required Information

1. Total system water content

Gallons
2. Initial fill water temperature

F
3. Maximum water temperature

F
4. System fill pressure

PSIG
5. Maximum pressure (10% below relief valve)

PSIG

Tank Selection

6. Enter total system water content (form line 1)

Gallons
7. Enter Expansion factor from Table 1
8. Expanded water volume( line 6 X line 7)

Gallons
9. Acceptance factor from Table 2
10. Total tank volume required (divide line 8 by line 9)

Gallons

Thermal Tank Chart

Select a Flexcon tank below which satisfies both line 8 and line 10. For larger systems, multiple tanks may be manifolded together to meet system requirements. For systems containing propylene glycol please contact customer service.

PH & WHV Series and ASME
Model Total
Volume
(gallons)
Maximum
Acceptance
(gallons)
Dimensions
Diameter
(inches)
Length
(inches)
Weight
(lbs)
ASME* Non-ASME
PH 5C PH 5 2.1 1 8.5 11.5 7
PH 12 C PH 12 4.5 2 10 15 10
PH 25 C PH 25 6 3.8 12.5 19.2 11.5
PH 30 C WHV 50 15 6.3 16 21.7 32
PH 42 C WHV 75 20 9 16 28.8 39
PH80 C WHV 120 33 14.4 16 27.8 60
PH 100 C WHV 165 44 19.8 21 36.2 72
PH 180 C WHV 320 81 38.3 21 44.4 140

*Dimensions for ASME tanks are different. Please refer to the ASME section

Table 2
Acceptance Factors
 Hydronic and Thermal tanks
Po Maximum Operating Pressure (PSIG) Pf-Minimum Operating Pressure at Tank (PSIG)
  12 20 25 40 50 60 70 80 90
27 0.36 0.168              
30 0.403 0.224 0.112            
50 0.587 0.464 0.386 0.155          
70 0.685 0.59 0.531 0.364 0.236 0.118      
90 0.745 0.669 0.621 0.478 0.382 0.287 0.191 0.096  
110 0.786 0.723 0.682 0.561 0.481 0.401 0.321 0.241 0.16
130 0.815 0.76 0.726 0.622 0.553 0.484 0.415 0.346 0.277
150 0.838 0.789 0.759 0.668 0.608 0.547 0.486 0.429 0.365
Table 1
  Expansion Factors
Final Temp Initial Temperature
  40 50 60
100 0.00575 0.00569 0.0052
110 0.00771 0.00765 0.00716
120 0.01004 0.00998 0.00949
130 0.01236 0.0123 0.01181
140 0.01501 0.01495 0.01446
150 0.01787 0.01779 0.0173
160 0.02092 0.02086 0.02037
170 0.02418 0.02412 0.02363
180 0.02763 0.02757 0.02708
190 0.03127 0.03121 0.03072
200 0.0351 0.03504 0.03455
210 0.03911 0.03905 0.03856