The 9500 control valve uses a 1.5” gallon meter either mechanical with a black flexible cable that pushes into the meter dome as seen in the picture. The meter dome can be a PVC dome or a brass dome. Inside the meter dome there are more than a dozen small reduction gears that react to the impeller inside the brass housing as it spins registering gallons. This dome can be standard range 0 to 100 times 100 for registering up to 10,000 gallons (100 x’s 100) #15218
or extended range 0 to 50 x’s 1000 registering up to 50,000 gallons #15237
. The picture of the gallon wheel indicates that the meter dome being used on this control is a standard range dome. The white dot above the numbers is the set point which in this case is 9,900 gallons. After switching tanks the fresh tank starts at the set point 9,900 and counts down as soft water is used. At any time you can look at the gallon capacity triangle and it will be pointing at the number of gallons left on the in service tank before it switches to the stand by tank and begins a regeneration.
A digital 9500 will have a like gallon meter but the meter dome will have a recessed slot and a securing screw for a digital wire end plug. This digital meter wire sends digital pulses back to the electronic control board to register gallons. The capacity for this meter is 0 to 999,000 gallons, meter dome #14716.