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My Amtrol SF-20 is cycling wildly from 90 down to about 30. Water runs at low pressure then up for about 10-15 seconds then back down again for about 30 seconds. How do I clean/service the unit and replace air? The service tag says it is a 90psi unit.

Posted by stormyehitch on


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I can't find that model number on the Amtrol site, please check it.
Is this a water storage tank? With an air charge?
If so:
Remove the dust cap on the charging valve on top, Schrader valve, like a car tire.
Use a small tool to slightly depress the pin in the middle.
If water comes out, the tank should be replaced but adding air will help for a while.
If air comes out, you can pressurize.
Determine the pump turn on and turn off pressures using a good pressure gauge.
Turn on may be 30 psi, turn off should be around 50 psi, TYPICALLY.
Switch the pump off.
Open a valve and drain all pressure from the water system.
Get a tire pump and pump up the tank pressure through the top valve to 2 psi lower than the pressure that the pump turned on above. If the pump turned on at 30 psi, pump up to 28 psi.
Put system back in service.

Posted on Feb 13, 2011

  • Anonymous Feb 13, 2011

    I would like to add that there could be a pump problem, rather than a tank problem, but I don't know enough about your system.




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