Rain soft problem

That is probably the issue. If we are talking about the same valve I think we are either the Silver and Gold series, newer EC4 valves or any AQC. I can help you in great detail. Please let me know what unit exactly so I can make sure all of this information provided is correct.

Although dependent on how old the system is you nay need the seals replaced inside the valve. Or we can go through these steps to look for foreign material. This is something that can be done with a couple of screwdrivers, 1 Phillips , 1 flathead and some towels. You will also need a silicone based o-rind lubricant (DOW-111) available at machine shops and some hardware stores.

First you need to put the unit on BYPASS so that no water continues to run through the softener (or you can turn the water off to the house or the softener if there is a valve on your plumbing on the RIGHT hand side looking from the front). If you do turn it off and open up a faucet in your house to make sure you don't have any water flow and to relieve any pressure.) Shutting water down before the softener is recommended.
BYPASS: This can be done on the back of the valve where the inlet and outlet plumbing goes to the softener. You should have a key (looks like a T). Right where the water comes in you will see two valves accessable on the top side. These only turn one way and if you are hearing water run they will be in this position (!)(!) you need to turn both so they are like this (-)(-) Please see your manual if you need any help on this part. Water will still run in the house if only on BYPASS.

Now we need to relieve any pressure in the tank itself.

On the back of the unit there is a plastic cover which you need to remove. It slopes down at an angle and may have the MADE IN USA sticker on it.

Remove the two small phillips screws on each side. keep them with the cover. Now you should see a long stem sticking up on the back with 1 screw in the middle to center it. If you are looking at this we are still in good shape.

Unplug the Unit from the back. It should be a white plug. If not unplug it from the wall and make sure you have some slack in the line as we are going to remove the electronics from the valve here shortly.

If it is a computer controlled system (water metered GOLD and EC4) unplug the water meter itself. It is rather hard to describe its location, but it will be a black wire and the only wire protruding from the electronics in the fromt. It should be right in the middle closer to the valve and directly in between the valve and the bypass. Pull it straight up (or down if bypass is backwards). It should come out without any problems and the wire should still ge back into the electronics.

Now hopefully this is making some sense.

There is a white plunger on the right had side facing up. It will be near the tube that goes down to your brine tank (not the drain). take your flat head screwdriver and press it down and hod it for a few seconds. You should hear water run then STOP. All the pressure should be out of the system.

Remove the two flat head screws (left and right facing UPWARD on the valve near the stem I was talking about earlier leave the middle one alone for now. Also remove the one small phillips from the stem that centered it.

Now you should be able to remove the electronics from the rest of the system. Gently work it towards you and it should come off. Place these somewhere that they won't get wet.

At this time by no means should you be leaking water anywhere on a consistent basis.

Now you are looking at the valve itself with just that stem piece sticking up.

remove the other three flathead scrws facing up



Remove the three screws (FACING UPWARDS) near the back of the electronics.

The valve should be able to be pulled out at this time. Some times it is stubborn and you may need to gently pry on the plastic top to coax it out. A little water may come out and then so have your towels ready. It should stop and not continuously run. If so you still have water under pressure to the softener

Once out you should be holding in your hand a green valve. Check to make sure it is no heavily scratched or scored. DON'T DROP IT! Place aside.

now you can stick your finger down in the hole where it was a bring out all the seals and spacers there should be 5 of them. check them for any debris especially little white "balls" also known as resin. Clean them with water
and get any of the build up off of the spacers.

The rubber rings you are holding are the actual seals and you will need to purchase them from Rainsoft. If you want to replace them at this time.

Lube up these seals with the DOW-111 and replace from bottom to top. There is 1 seal between each spacer and one seal on the very top to keep it from leaking.

Insert the green valve back in and press it down. Replace the three screws and tighten then like you would the lugs on a tire in a cross fashion to that you can make sure that you aren't trying to shove the cover on sideways. You can make these fairly tight but by all means don't strip them out.

Now reverse the process. Getting the electronics back on is tricky but can be done. There are two tabs at the bottom that go into the valve so start on the bottom side. You will also need to move the valve itself by hand on the stem to get everything to line back up. Also, the words Rainsoft and or numbers are present on one side of the stem. They must be out so you can read them when the electronics are connected otherwise the system will not work right. REverse everything else except pushing the plunger down like we did earlier to relieve the pressure.
When you have the electronics back on the unit and all of the phillips screws that go to the valve are in SLOWLY turn the water back on so check for any leaks! If none them continue putting the thing back together.

1 phillips screw on the stem/
2 water meter wire that you pulled out
3 power to the unit.

Start at manual regeneration and keep looking for leaks.

If none replace the cover that may have said MADE in USA

amazing answer, also so useful in 2017. DO you know why there was a constant flow of water? Thanks. Bob

Post a picture of the control valve so we can see what model you have.
Front, back & side.