3M under sink reverse osmosis; trying to sanitize it. Manual says to empty the tank. Manual says the tank will feel light when empty. Water eventually stops running, but the tank is still heavy.

There is a problem with the automatic shutoff. There may be carbon fines or debris in it. When the shutoff is trying to close it will have a chirping or light honking noise. Try running all the water out of the tank Make sure you clean and sanitize the filter housings when changing filters.
Here is a link for Culligan RO manuals.
http://www.freshwatersystems.com/t-manuals.aspx

RJ

The storage tank probably has low air pressure. On a 3 gallon RO tank empty the tank completely of water and adjust tank pressure to 7psi.
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

I would pull out all the filters changed and check them. If a GAC filter is used as the post filter, before the RO tank, carbon fines can come out of the filter and can plug up the head on the RO system. Make sure the sediment pre-filter is not plugged and there is plenty of water supply. You may have lost pressure in the RO tank. A 3 gallon tank should have 7psi pressure when totally empty.
RJ

Sanitizing the reverse osmosis system each time you change filters is a good practice. It is very easy to introduce bacteria into the RO system simply from your hands. I prefer to clean the housings with a tablespoon of bleach and rinse them thoroughly. Most RO systems now have TFC membranes, these membranes are susceptible to chlorine damage so it is important that any bleach not come in contact with the membrane. Changing of the capillary tube should be done about every 3yrs or if any iron is present sooner. It also helps to wear latex gloves when changing filters to prevent introducing bacteria into the RO. If this is done you may get by with sanitizing every other time. Make sure you dump at least 2 tanks of water after installing new filters and sanitizing.
RJ

Typically a reverse osmosis storage tank should have a precharge of approximately 7 psi. Depending on the make/model of your tank it may have a higher charge currently which would cause the tank to not fill. There should be a schrader valve on the bottom or side of the tank. Using a tire gauge and bicycle pump you should be able to check the current pressure in the tank and adjust it up or down to 7 psi.

reverse osmosis storage tanks: http://www.freshwatersystems.com/c-32-reverse-osmosis-storage-tanks.aspx

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

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

Hello, first open the Reverse Osmosis faucet and see what the pace of the drip or water stream is. It should be a constant rapid drip. If it is, next disconnect the drain line of the RO System from the Drain Saddle Clamp attached to the plumbing under the sink. The Drain Water should be a "Steady Slow Stream" of water. If it is, next, take a Tire Pressure Gauge and attach it to the Shrader (Tire Valve) Valve at the bottom, side, or top of the storage tank to see what the air pressure is inside of the tank. The Tank pressure should be a minimum of 8-10 psi when completely empty of water. If the tank is empty you should be able to pick it up rather easy. If the air pressure is good in the tank, then next remove the primary Pre-Filter Cartridge from the first filter housing and reattach the filter housing. See if the Dripping from the RO faucet increases in Velocity or Pressure. If so, simply replace the filter. After performing these tests let me know what you discover. Thanks, Victor

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.

www.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