Another Pressure Tank Irrigation Problem
Pressure tanks are great for the proper applications, but too often I run into a system that should have utilized a pump-start relay instead of a pressure tank. But pressure tanks are great for house water or for any on-demand water system.
Pressure tanks eventually go bad. The diaphragms or bladders inside them go bad and they no longer continue to hold air pressure. The tanks naturally loose air due to attrition (natural air loss) over time and may just need a re-boost or re-fill to the proper air pressure level.
You need a typical or standard tire pressure gauge to do this. You also need to determine the pressure switch's cut-on and cut-off pressure. This can be determined first by looking at the inside cover of the pressure switch cover, and then verified by measuring the air pressure in the tank when the pump cuts on and cuts off.
As a rule of thumb, I adjust the tanks to 2psi less than the pressure switch cut on/off psi adjustments. For instance, if you have a typical 30/50psi switch then I will set the air in the pressure tank to 28 psi to cut on and thus will cut the system off at approximately 48 psi. This was taught to me by a well driller that I worked with for many years.
I do not recommend the use of pressure tanks with horizontal centrifugal pumps! Without adjusting the spread screw just right, you wil have problems. and this can prove to be more difficult than it seems; trust me, if I have been through this many times! I centrifugal pump will only get up to like 40 - 45 psi. A jet pump will run from 50 - 70 psi typically depending on system design and volume of water source. This makes using pressure switches on jet pumps much easier.
With submersible pumps and jet pumps, pressure tanks and pressure switches can be beneficial if designed, sized, and used correctly. The whole point of a pressure tank is too reduce stress on the pump. But if your pump is continuously turning on and off then you are causing more harm to your pump then if it just runs longer. This happens when a tank is undersized or used with the wrong type of well and pump setup.
For irrigation systems, a like using pump-start relays instead of pressure tanks. For house water or on-demand water systems, then a pressure tank is necessary. Just make sure that if you are doing this yourself, that you consult with your irrigation supplier to make sure that you get the right parts, do not under-size your tank, and get the correct pressure switch needed for your particular water application.
Scotthttp://www.autolawnsprinklers.com
Pressure tanks eventually go bad. The diaphragms or bladders inside them go bad and they no longer continue to hold air pressure. The tanks naturally loose air due to attrition (natural air loss) over time and may just need a re-boost or re-fill to the proper air pressure level.
You need a typical or standard tire pressure gauge to do this. You also need to determine the pressure switch's cut-on and cut-off pressure. This can be determined first by looking at the inside cover of the pressure switch cover, and then verified by measuring the air pressure in the tank when the pump cuts on and cuts off.
As a rule of thumb, I adjust the tanks to 2psi less than the pressure switch cut on/off psi adjustments. For instance, if you have a typical 30/50psi switch then I will set the air in the pressure tank to 28 psi to cut on and thus will cut the system off at approximately 48 psi. This was taught to me by a well driller that I worked with for many years.
I do not recommend the use of pressure tanks with horizontal centrifugal pumps! Without adjusting the spread screw just right, you wil have problems. and this can prove to be more difficult than it seems; trust me, if I have been through this many times! I centrifugal pump will only get up to like 40 - 45 psi. A jet pump will run from 50 - 70 psi typically depending on system design and volume of water source. This makes using pressure switches on jet pumps much easier.
With submersible pumps and jet pumps, pressure tanks and pressure switches can be beneficial if designed, sized, and used correctly. The whole point of a pressure tank is too reduce stress on the pump. But if your pump is continuously turning on and off then you are causing more harm to your pump then if it just runs longer. This happens when a tank is undersized or used with the wrong type of well and pump setup.
For irrigation systems, a like using pump-start relays instead of pressure tanks. For house water or on-demand water systems, then a pressure tank is necessary. Just make sure that if you are doing this yourself, that you consult with your irrigation supplier to make sure that you get the right parts, do not under-size your tank, and get the correct pressure switch needed for your particular water application.
Scotthttp://www.autolawnsprinklers.com
posted by Irrigationman at
7:05 PM
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