Email: - Phone: 610-666-1220


ASME Bladder Type Hydro-Pneumatic Tanks

In contrast from diaphragm tanks, bladder tanks completely enclose the water inside a replaceable butyl rubber bladder (other bladder materials available upon request), eliminating problems such as water-logging and tank corrosion.  Air precharge pressure is maintained using a car-tire type valve, also known as a Schrader valve.

Hydro-pneumatic tanks help protect the pump and pressure switches in a system against short-cycling.  The tanks are designed to deliver water under pressure between pump cycles to meet demand, also known as the required tank drawdown.  Hydro-pneuamtic tanks improve the system operation and extend the pump motor service life by reducing surge pressures, dampening pressure spikes, and minimizing pump run times.

Similar to other items in a heating or cooling system, bladder tanks must be maintained to ensure proper operation.  Precharge pressure must be field adjusted per the operating conditions of the system it is being installed in.  See IOM for more details regarding proper maintenance procedures.

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The John Wood Company, LLC

Phone (610) 666-1220
Fax (610) 666-0193
Toll Free (800) 537-5581

Remit To:

The John Wood Company
PO Box 644250
Pittsburgh, PA 15264

Mail to:

The John Wood Company
PO Box 364
98 Highland Avenue
Oaks, PA 19456

Ship To:

The John Wood Company
Highland Business Park
98 Highland Avenue
Oaks, PA 19456-1052

NOTE: We are NOT affiliated with the John Wood Water Heater Company of Canada. They may be contacted at 1-888-599-2837, e-mail at or at