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Non-Potable Water Expansion Tank Sizing
 

TO PROPERLY SIZE A WATTS REGULATOR SERIES ET, ETX, ETSX, ETA or ET-RA NON-POTABLE WATER EXPANSION TANK:

Enter the appropriate information in the boxes below..
* Required Fields
System Volume *
System volume must include the total capacity of the boiler, piping, heat exchangers, radiation, etc.
 Gallons
Supply Pressure *
The set pressure of the boiler fill valve.		 PSI

Air Pre-Charge *
15psi Air Charge is Standard.

 PSI
Relief Valve *
The set pressure of the relief valve. 		PSI
Inital Temperature - Start *
NOTE: The lowest setting of the aquastat.		 °F
Max Temperature - End *
NOTE: The maximum setting of the aquastat.		 °F
Expansion Factor
Calculated Acceptance Volume Gallons
Calculated Total Volume Gallons
I have a system with Ethylene Glycol
I have a system with Proplene Glycol
None of the above apply to my system
WATTS Model Tank Volume
(Gal) 		Tank
Acceptance
(Gal) 		MAX. PRESSURE (PSI)
Model ET
ET-15 2.1 1.4 60
ET-30 4.7 3.0 60
ET-60 6.6 4.3 60
ET-90 13.0 8.0 60
Model ETX mounts to supply piping
ETX-15 2.1 1.0 75
ETX-30 4.5 2.5 75
ETX-60 6.0 3.0 75
ETX-90 15.0 6.0 100
Model ETSX is free standing
ETSX-30 15.0 6.0 100
ETSX-40 20.0 8.0 100
ETSX-60 33.0 13.3 100
ETSX-90 44.0 17.7 100
ETSX-110 62.0 24.9 100
ETSX-160 81.0 32.6 100
ASME Pressurized Expansion Tanks
Fixed Bladder Type
ETA-15 7.5 2.5 150
ETA-20 10.9 2.5 150
ETA-40 25 10 150
ETA-60 35 10 150
ETA-80 45 21 125
ETA-100 60 21 125
ETA-120 70 48 125
ETA-144 80 48 125
ETA-180 90 48 125
ETA-200 115 48 125
ETA-240 140 52 125
ASME Pressurized Expansion Tanks
Removable Bladder Type
ET-RA 35 10 10 125
ET-RA 50 13 13 125
ET-RA 85 23 23 125
ET-RA 130 35 35 125
ET-RA 200 53 53 125
ET-RA 300 79 79 125
ET-RA 400 106 106 125
ET-RA 500 132 132 125
ET-RA 600 158 158 125
ET-RA 800 211 211 125
ET-RA 1000 264 264 125
ET-RA 1200 317 317 125
ET-RA 1400 370 370 125
ET-RA 1600 422 422 125
ET-RA 2000 528 528 125
HIDE CHART
  1. Using the calculated acceptance volume and the calculated total volume, select a tank from the chart to the right.
    • Tank volume of the selected model must be greater than the calculated total volume.
    • Tank acceptance of the selected model must be greater than the calculated acceptance volume.
    Note: Both the Tank Volume and the Acceptance Volume must be greater than the calculated volumes as indicated.
  2. A pressure reducing valve should be installed on the supply when system pressure exceeds 80psi.
  3. To accommodate the thermal expansion required for higher temperature and/or higher pressure systems, multiple tanks may be used. Please contact the factory for sizing information.
  4. For complex tank sizing for multiple apartments/condos, please contact the factory for sizing information.
  5. The potable water expansion tank shall be installed in the cold water service pipe line on the supply side of the water heater (or water storage tank).
 
   
     
     
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