Expansion Tanks (Fiberglass Non-ASME)


Tank Setup Information

  • Corrosion-proof composite construction – From the high density polyethylene inner liner to the fiberglass-wound and epoxy resin-sealed outer shell, WM-Series tanks contain no steel. So they can’t rust.
  • Little or no maintenance – Because they contain no steel, there is no paint to scratch or touch up.
  • Longer life, greater flexibility – Our unique air cell offers longer life than the bladders or diaphragms in steel tanks. WM-Series tanks can be installed with a wider range of pressure settings, so you can select the system pressure you want. What’s more, the bottom inlet/outlet assembly is pre-installed and comes with system connections to save time and money.
  • Light weight – WellMate tanks are quicker, easier and less costly to install than steel tanks.
  • NSF and/or FDA listed materials – The complete assembly meets stringent US requirements for water components. WellMate tanks are environmentally safe, 100% lead-free. They will not introduce undesirable chemicals or elements into your customers’ water.
  • Replaceable air cell – Easy to service in the field.
 Model Number  Capacity
gal/liter
 Max. Operating Pressure
psi / kPa / bar
 Drawdown 30/50 Setting
gal/liter
 Diameter
inch / cm
 Overall Height
inch / cm
Height inlet/outlet to floor
inch /cm
 System Connection Assembly Weight
lb / kg
 WM-6  19.8 / 75  100/700/7.0  5.9 / 22.5  16 / 41  32 / 81  1¾ / 4.4  1″ male NPT  17.75 / 8.1
 WM-9  29.5 / 112  100/700/7.0  8.9 / 33.5  16 / 41  44 / 112  1¾ / 4.4  1″ male NPT  24.75 / 11.2
 WM-12  40.3 / 153  100/700/7.0  12.1 / 45.8  16 / 41  57 / 145  1¾ / 4.4  1″ male NPT  30 / 13.6
 WM-14WB  47.1 / 178  125/862/8.6  14.1 / 53.5  21 / 53  41¼ / 105  2¼ / 5.7  1¼” male NPT  43 / 19.5
 WM-20WB  60.0 / 227  125/862/8.6  18.0 / 68.1  24 / 61  41½ / 105  2¼ / 5.7  1¼” male NPT  50 / 22.7
 WM-25WB  86.7 / 328  125/862/8.6  26.0 / 98.5  24 / 61  55¼ / 140  2¼ / 5.7  1¼” male NPT  72.75 / 33.0
 WM-35WB  119.7 / 453  125/862/8.6  35.9 / 135.9  24 / 61  74¼ / 189  2¼ / 5.7  1¼” male NPT  95 / 43.1


We also have a similar tank of steel construction made by Little Giant