When installing a water system, sometimes installers run into challenges when commissioning a water system. This article covers some of the recurring problems that we are seeing along with solutions to these problems. We are assuming that the water system has been properly commissioned but the control is still not at an optimum situation.
At some facilities, the customer may be using reverse osmosis(RO) water. According to Wikipedia, reverse osmosis is a water purification process that uses a partially permeable membrane to remove ions, unwanted molecules and larger particles from drinking water. This process also removes the bicarbonates from the water. Normally when you add acid, the bicarbonates bind themselves to the acid you are adding. This neutralizes some of the acid and will result in minor changes in the pH level. If there are no bicarbonates in the water, the acid will have nothing to bind to and you will see large swings in acidity of the water which you will not be able to control. The only solution would be to add bicarbonates to the RO water so that you have a buffer in it.
Another challenge shows up if the customer wants to use organic fertilizer. The organic fertilizer tends to leave a buildup of surface scum inside the water system. This surface scum is a visible film of micro organisms and can cause problems by plugging filters and interfering with the proper operation of the flow sensor. Since the dosing control is influenced by the amount of flow, the dosing will incorrect if the flow sensor is not spinning freely. This problem is more obvious at low flows. This problem can only be solved by cleaning the water system.
A commonly overlooked installation issue is the location of the flow sensor. The manufacturers of the flow sensors have specific instructions on the location of the flow sensors. If the flow sensor is too close to an elbow or a reducer in the pipe, the water will be turbulent and flow reading will be inaccurate. Also check with the manufacturers instructions on the orientation of the flow sensor. On a horizontal pipe, the flow sensor needs to be oriented facing up. On a vertical pipe, the flow sensor needs to be mounted where the water is flowing upwards.
Finally check the specifications of your water system. Priva's water systems operate well between 10% and 100% of the unit capacity. If you are operating at less than 10% capacity, your dosing accuracy will diminish considerably.