Water tank how do i drain water storage tank ?

no info generic answer ---owners manual ---manufacturer --rv dealer ---rv service center

It sounds like a couple things. First, ensure the bypass valves are closed. There should be two near the city connection that drains water from the general water lines to your camper. The other will be to drain the fresh water storage tank. If the pump is running and the drain valves are closed, the water should be directed into the camper faucets and toilet.

IS that the drain for winter time storage that is open?

open all faucets and drain water by removing hose and opening inlet valve.drain both sewage tank and grey water tank. if used drain fresh water tank . leave at least one faucet open. if possible blow air through lines to remove any excess water.Make sure your engine has adequate
antifreeze in it. check air in tires.spray all vehicle leveler jacks with WD40. cover vehicle with tarp or put in garage or storage unit . Best to park inside out of elements. Phil Anderson

This unit features the patented AutoDrain NanoMist Technology that Vaporizes excess fluid build up, eliminating the need to drain the unit. Most of this water is used to cool the unit and make it run more efficiently. This unit has a built-in water tank (non removable) with a drain outlet for end of season draining and storage purposes

The storage tank is probably bad. Shut all the water off to the RO, drain all the water from the RO tank, check the air pressure with a low pressure tire gauge. PSI should be 7psi with a 3 gallon tank. 12psi with a 10 gallon tank.
Add air to tank with a bicycle pump.
RJ

When you put air in the tank did you make sure all the water was out of tank? In a three gallon tank there should be 7 lbs of air, 10 gallon 10 lbs of air.
There can be many reasons for no water in tank.
1. Bad bladder in holding tank. No back pressure on membrane (all water going to drain)
2. Faulty membrane (all the water going to drain)
3. Bad capillary tube (all the water going to drain)
4. Plugged check valve at top of membrane (no water)
5. Faulty water feed valve (piercing valve)
6. Fines from post carbon filter have plugged up the manifold (head) of RO unit.
7. Bad valve on RO tank
8. Plugged drain line
RJ

storage tank is water logged, drain tank completely, allow air into it, seal and return to service

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