How do you change the filters in a Culligan RO system

yes you answered your questions there. i researched info and more than likely it is the valve

http://watersoftenernews.blogspot.com/2014/02/culligan-water-softener-noise.html

You can get replacement cartridges for all the H series through AC series RO systems on line from several suppliers. I use them and they work just fine.
RJH2O

Pre-filter and carbon block filter are changed annually. The membrane is only changed every 3-7 years depending on water quality coming in, TDS and usage. Fourth filter is an in-line carbon filter that goes on the line up to the RO faucet.
RJH2O

This usually indicates low pressure in storage tank. A 3 gallon tank should have 7psi pressure when completely empty. Also if the unit is fed by a piercing valve it may be faulty and not supplying enough water to RO.
RJ

This happens when the cold water is run. As cold water is drawn water is being pulled from the inlet of the RO system. This will cause a whine or squeal from the RO. Install an in-line check valve on the feed line to the RO system. This should alleviate the problem.
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

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

It helps to sanitize the RO system each time you change the filters. Always test the RO water with a TDS meter to determine if the TDS rejection has dropped below 80% rejection. If it has the membrane should be changed along with the other filters. Always wear latex gloves when changing RO filters to prevent bacterial contamination. There are complete instructions on sanitizing the RO in the Culligan manual. Here is the link for the AC30 Manual.
http://www.freshwatersystems.com/support/AC-30.pdf

RJ

Depending on the model of your system here is a link to the manuals for Culligan Units.

http://www.freshwatersystems.com/t-manuals.aspx

Please see the below link for a pdf file and it should explain the procudure for filter changes for the Culligan AC-30 RO Water System

http://www.freshwatersystems.com/support/AC-30.pdf


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