GE-based Reverse Osmosis System - Tank doesn't fill

[AzJazz]

Hi, guys!

I have a 4-stage Reverse Osmosis built from GE parts. The RO was installed professionally by an out-of-business local company, using their system part number (which I don't know).

 

It looks like a fairly standard installation. The attached diagram (from another company) matches exactly with what I have installed (parts and plumbing).

 

This weekend, I decided to replace all my filters - it has been 3 years, and long overdue.

 

Everything is reconnected (matching the diagram), and I am having a problem where the RO storage tank doesn't seem to be filling up properly. RO water is coming out of the system, but very slowly. I don't have anything installed where the "Check Valve" is indicated in the diagram, and haven't had anything there for the last 3 years.

 

I read today on the 'net that I should have a check valve installed for the "Shut-Off Valve" to work properly. I did have the mesh filter and valve, so I decided to install the check valve.

 

The check valve is now installed, and now almost nothing comes out of the RO faucet. Nothing is still getting into the storage tank.

 

What is going on?

 

Thanks,

 

AzJazz

[BryanS]

I've never worked on these, but just had thought. What kind of shutoff valve does this have? I'm just thinking that maybe the shutoff could have went bad after shutting it off and turning it back on. If it's a saddle valve like in that picture. I would check the water pressure coming out of the valve itself. Any chance the tank has some kind of air relief? Maybe it is airlocked. I have a training book from Sears. I'll take a look when I get a minute, and see if anything in it is of use.

[BryanS]

From what I've found in my book is the relief is usually built into a T-fitting hooked to the drain tube. I would check water pressure going to the system. I would then unhook the hoses to each part and check flow out of them. Those fittings are usually like the John Guest fittings I believe. Where you take out the clip and push the ring in while you pull out the tubing. Plus if it is air locked purging each part with water may fix it. Like I said, I nevered work on one before, but I'm just thinking out loud

[SANTA]

I've installed 2 of the APEC RO under sink systems and what I am thinking is maybe your post filter is backwards or maybe one of your valves isn't opened all the way. It's a very simple water pressure design so the fix has to be simple as well.

[kdog]

On your storage tank ther is a schraeder valve, this is to allow air pressure between the wall of the tank and the bladder so that it will build pressure to dispense - open the produ t water valve and allow it to fully drain the tank, then depress the schraeder valve so the tank fills to atmospheric pressure.  Allow approx 24 hrs for the unit to process a full storage tank then you should be OK

Did you replace the membrane at the same time ? It is important that you install that in the right direction.

[Samurai Appliance Repair Man]

Moved to the Water Treatment forum.

[AzJazz]

Hi, guys - I'm still working on this. I don't know if it is operating yet.

 

I re-pressurized my RO tank bladder to 5 PSI. I think it was pretty much empty.

 

One question ... When I first connect my RO supply lines, and the RO tank is totally empty, will I only see a little dribble from the RO faucet when it is first turned on? I see almost nothing coming from the RO faucet ever since I put a check valve into the system (there wasn't a check valve in the system the last few years).

 

If I remove the check valve, I see a weak, but more reasonable stream.

 

AzJazz

[SANTA]

If the check valve isn't original equipment then take it out. I don't know what size tank you have but it can take many hours to fill. The less water in the tank the lower the pressure.

[kdog]

You need to have your tank to atmospheric pressure (14.7 psi) - drain the tank completey, then depress valve for a minute, the static pressure in the room will fill the area between the bladder and tank, then when the tank (bladder) is full - the atmospheric pressure will act as a cushion to dispense water.   The unit will take up to 24 hours to fill the tank, so a gallon or so will be available. If you require more than this, fill a container and refrigerate and repeat process.  while the unit is processing, you will hear a slow dribble of water down the drain

[kdog]

As a rule, the check valve is built into the membrane housing - be certain that the membrane is installed in the right direction

[AzJazz]

If the check valve isn't original equipment then take it out. I don't know what size tank you have but it can take many hours to fill. The less water in the tank the lower the pressure.

 

@Santa - It's been a few years, but I think that a check valve might have been installed originally. The last time that replaced the filters a few years back, I believe that it fell out - and I had no idea where it came from. At the time, I didn't have the same diagram that I attached to this posting - which now shows where a check valve is inserted.

 

You need to have your tank to atmospheric pressure (14.7 psi) - drain the tank completely, then depress valve for a minute, the static pressure in the room will fill the area between the bladder and tank, then when the tank (bladder) is full - the atmospheric pressure will act as a cushion to dispense water.   The unit will take up to 24 hours to fill the tank, so a gallon or so will be available. If you require more than this, fill a container and refrigerate and repeat process.  while the unit is processing, you will hear a slow dribble of water down the drain

 

As a rule, the check valve is built into the membrane housing - be certain that the membrane is installed in the right direction

 

@kdog - I drained my tank (it looks like it is about 2-3 gallons), and then found an accurate low pressure gauge (1-20 psi) at the auto store. I pressurized the tank bladder to 5 psi when the tank was empty.

I'm 99.9% sure that I have the RO membrane installed in the right direction - it seems like there was only one logical way to put it in the housing.

 

Your comment on the check valve being built into the membrane housing makes a lot of sense, and makes me wonder if I have 2 check valves in the loop now. If I take the system apart, will I be able to see if a check valve is in the housing?

 

While it seems like the system is working pretty much OK with the (possibly extra) check valve installed after the RO filter, I still am not sure that the system is working the way it is supposed to. This is the first RO system I have owned.

 

I know that there is a huge difference in water flow rate if I remove the check valve that I inserted. My RO membrane is a 24 gallon-per-day unit. With the tank empty and the "new" check valve installed, the flow rate from the RO is not much above a trickle - pretty much what I would see if I barely turned on a normal faucet and see a stream. If I remove the "new" check valve and the tank is empty, the flow rate pretty steady at about 75% of what I would see with RO the tank full. 

 

The first (slow trickle) flow rate might actually be closer to a gallon per hour, though. I just don't have enough experience to know if what I have now is the proper operation.

 

Cheers,

 

AzJazz

Edited December 24, 2013 by AzJazz