Ro system tank will fill completely

If the RO is not shutting off and there is no water from tank there are several things to check.
1. The product water tank is probably low on air. The tank may be full but no water will come out. Put enough air in tank to force out all the water then reset air pre-charge to 7psi for 3 gallon tank.
2. The capillary tube / check valve of RO system is bad. This puts back pressure on membrane to help create water.
3. The Automatic shutoff is not working, causing the unit to run constantly.
I would have to know what model RO it is to narrow down the problem further.
Depending on the Membrane production 10, 25 gpd, etc. and the TDS of water it may take 24 hrs to fill the tank.
RJ

Here are the steps to remove your RO system. Put a pan and a couple rags under sink to catch any water that might spill.
1. Label all the lines from RO (with masking tape) to remember where they go.
2. Turn the water off to RO system
3. Run all the water from the RO tank
4. Turn the valve off on RO tank.
5. Remove the line to the RO tank and pull tank out.
6. Remove the line to the RO drain.
a. If there is an AIR GAP faucet this line may go there first
b. plug the whole for RO drain or replace the standpipe
7. Remove the product line from RO faucet
8. Remove the water line feeding the RO system.
9. Make sure the valve feeding RO is shut off completely
a. If this valve is a piercing valve you may want to consider replacing the section of copper
plumbing because it will eventually leak if left unused.
10. When re-installing the RO remove old filters, sanitize system and replace with new filters.
RJ

Make sure all the lines are hooked up correctly. It is going to take 3-8 hours to fill a 3 gallon RO storage tank. It depends on the capacity of the membrane (IE: 14, 20, 30, 50 or 75 gpd). It also depends on the TDS of the water. Water that has high TDS 500+ppm will take longer to produce product water than TDS of 100ppm. Check the pressure in the RO tank. When empty (In a 3 gallon tank) there should be 7psi pressure. A ten gallon tank takes 10psi. If it needs air you can use a bicycle pump to add appropriate air. Make sure the tank valve is turned off when adding air.
Do not use the RO faucet for several hours to allow tank to fill up. Also you should dump the first couple tanks of RO water to make sure any carbon fines are rinsed out.
RJ

There are several things to look for here.
1. Turn the feed valve off. Take the product line off the RO tank (shut the tank valve off first), turn
the feed valve back on and see if water is coming out the product line to RO tank
2. Make sure the feed valve is supplying water. If it's a piercing valve they can get plugged with debris.
3. Make sure there is water going to the drain
4. If the filters were just replaced, remove them, inspect them thoroughly and re-install
5. In an empty 3 gallon RO tank there should be 7 psi pressure. If there is too much pressure it will
prevent the tank from filling up.
6. Make sure there are no kinks in any of the RO lines.
RJ

Too much pressure in holding tank will not cause leaks in the RO unit. All too much pressure in tank will do is cause low or no product water in RO tank. Older Culligan RO systems (H8, H83, H5) had fittings that used metal locking washers and these can cut the RO line after the RO has been moved around while changing filters. Newer styles (AC30, Water Tower) use quick connect fittings and the RO line may work loose after filter changes and system being moved around under sink.
Turn the incoming water off to RO, turn the water off on RO tank, open the RO faucet to relieve pressure and pull the line off feeding the RO tank, inspect (you may want to cut off a small portion of the line at the filter) check the o-ring and re-install.
RJ

A reverse osmosis system drinking water system will waste a certain amount of water for every gallon it produces.
1. The higher the TDS (total dissolved solids) the higher the ratio of waste water to product water.
IE: An RO on TDS of 1000ppm may require 7 or more gallons of water to waste to 1 gallon of product water. TDS of 100ppm will have about 3 gallons of waste to each gallon produced.
2. It also depends on the Membrane capacity. Membranes for residential RO systems come sized from 7-75 gallons per day. If you are a heavy water user and have a low producing membrane the RO may not shut off until it gets to rest at night and fill the tank.
3. There can also be a problem with the automatic shutoff on the RO. When the tank fills up and the pressure equalizes across the system the ASO (which is just a simple diaphram system) shuts the water off to the system.
4. If there is not enough pressure in the RO tank the tank may fill up but there may not be enough back pressure to shut the ASO off. So the waste and product water go down the drain and it runs constantly.
RJ

The RO tank will still fill up even without any pressure it just won't push any water out. If the RO tank lost pressure and it is a sealed tank, it should be replaced. The bladder is bad.
A 3 gallon tank should have 7psi pre-charge pressure, 10 gallon 10psi. There must not be any water in tank to set the pre-charge pressure.
If the RO tank is not filling up then there is another problem.
RJ

I am assuming based on your description that the system you have is a reverse osmosis system. If this is true, you most likely need to recharge the air pressure in your RO storage tank. I have included step-by-step instructions below. If you find that your tank is not holding air or the tank will not empty completely, the bladder inside the tank may be broken and the tank will need to be replaced. I have included a link to our selection of RO tanks as well. To recharge the tank you will need a bicycle tire pump and a tire gauge that will be capable of reading below 10 psi. If you don’t have one that reads in single psi increments, then a meter that starts at 5 psi will work.
http://www.freshwatersystems.com/c-32-reverse-osmosis-storage-tanks.aspx

1) Close the cold water feed valve (if you can’t locate this on your system, you may be able to turn off the cold water to your sink)
2) With the RO tank valve on, locate the valve stem on the bottom or side of the tank. (this will look like the air stem on a bicycle or car tire)
3) Remove the stem cap.
4) Drain all water out of tank through open RO faucet into sink. (Continue to leave the RO
faucet open throughout the entire procedure)
5) If the current tank pressure doesn’t empty the tank, apply tire pump to valve stem
and pump a few times. Flow will increase and then gradually decrease as
pressure equalizes. Do not overcharge the bladder during this procedure.
6) Repeat step #4 and #5 until tank is completely empty. (Tank is empty when additional
pumping produces no more water)
7) At this point, adjust EMPTY tank to exactly 7psi. (Gauge reading midway between 5
& 10psi is sufficient)
8) Turn off RO faucet.
9) Replace cap on valve stem
10) Open cold water feed valve.
11) The water is useable immediately; however, tank will take a few hours to completely fill.


Geoff D., CWS-I - WQA Certified Water Specialist
Fresh Water Systems, Inc - http://www.freshwatersystems.com 1.877.335.3339

Make sure that all valves are in the open position.
Try to recharge the water storage tank. Here are the steps to follow.
* In General: When any type shut-off valve handle is positioned so that it is parallel or in line with the tubing that enters the valve, valve is OPEN. When handle is turned perpendicular to tubing that enters valve, valve is CLOSED.

Necessary Supplies:
1) Tire Gauge marked in 5psi increments (ie 5, 10, 15, 20psi, etc.)
2) Bicycle tire pump for standard type bike tire valve
To recharge RO system tank:

1) Close cold water feed valve (valve located at some point along the cold water line from street plumbing).*
2) Leaving RO tank valve on, turn tank on side & locate valve stem on bottom side.
3) Remove stem cap.
4) Drain all water out of tank through open RO faucet into sink. (Continue to leave RO faucet open throughout procedure)
5) If current tank pressure is insufficient to empty tank, apply tire pump to valve stem and pump 10 – 15 times. Exit flow will increase and then gradually decrease as pressure equalizes. Do not overcharge internal bladder of tank during this
procedure.
6) Repeat step #4 until tank is completely empty. (Tank is empty when additional pumping produces no more water)
7) At this point, adjust EMPTY tank to exactly 7psi. (Gauge reading midway between 5 & 10psi is sufficient)
8) Turn off RO faucet.
9) Replace cap on valve stem and reposition tank in upright position.
10) Open cold water feed valve.*
11) System water is useable immediately, however, tank will take 3-4 hrs to completely refill.

FreshWaterSystems.com: The Water Super Store: 1-877-335-3339

This might be a possible tank pressure issue. This could also be a clogged filter. I would first check the tank pressure by using the following steps

Necessary Supplies:
1) Tire Gauge marked in 5psi increments (ie 5, 10, 15, 20psi, etc.)
2) Bicycle tire pump for standard type bike tire valve

To recharge RO System Tank:

1) Close cold water feed valve (valve located at some point along the cold water line from street plumbing).*
2) Leaving RO tank valve on, turn tank on side & locate valve stem on bottom side.
3) Remove stem cap.
4) Drain all water out of tank through open RO faucet into sink. (Continue to leave RO faucet open throughout procedure)
5) If current tank pressure is insufficient to empty tank, apply tire pump to valve stem and pump 10 – 15 times. Exit flow will increase and then gradually decrease as pressure equalizes. Do not overcharge internal bladder of tank during this procedure.
6) Repeat step #4 until tank is completely empty. (Tank is empty when additional pumping produces no more water)
7) At this point, adjust EMPTY tank to exactly 7psi. (Gauge reading midway between 5 & 10psi is sufficient)
8) Turn off RO faucet.
9) Replace cap on valve stem and reposition tank in upright position.
10) Open cold water feed valve.*
11) System water is useable immediately, however, tank will take 3-4 hrs to completely refill.

FreshWaterSystems.com: The Water Super Store: 1-877-335-3339