The pressure generated by spa jets is the result of water flowing through a narrow orifice in the rear of the jet, combined with air drawn into the space adjacent to the jet orifice via vacuum venturi action.
The combined mixture of air and water results in the aerated pressurised flow from the spa jet. The amount of air drawn in and the resultant additional jet pressure experienced is dependent on the water flow rate through the orifice.
Air flow to the venturi is generally regulated with an air control mounted on the spa. A well calculated spa plumbing system can generate what feels like double the jet pressure once the air venturi is fully open. An air control that can be screwed in/out allows for variable flow rates to be selected depending on the desired user jet pressure.
Insufficient water flow can result in the inability to draw air into the jet from the venturi. This can be an issue on spas with under-sized pumps or plumbing, easily avoided by ensuring pumps and plumbing are correctly selected to ensure each jet receives approx. 40Lpm to 50Lpm which is the optimal flow rate for proper jet action.
For more information contact technical support at Australian Spa Parts on 1300 736 025.