RO/DI system won't shut off. I'm stumped.

[Rychek]

Just over five years ago I purchased a Buckeye 100 gpd Reff/Residential RO/DI. I have used it daily since then for my reef and/or for drinking water. It has served my family very well. However, it never shuts off. It used to shut off (most of the time at least) when I lived in an apartment with water pressure closer to ~43 PSI, but the last 3.5 years I have been in a house with ~90 PSI line pressure and it never stops. In an effort to get the system to shut off when the storage tank is full, I pulled the tank to check the water pressure. As soon as I hit the Schrader valve, water came out. :( I ordered a new tank, pressure regulator, pressure gauge kit and a 75 gpd RO membrane (figured I was way overdue to for a replacement) on Monday night based on the assumption that my line pressure is too high and broke the membrane in my storage tank. The parts arrived today and I installed the tank, regulator and pressure gauge with the gauge in-line before the regulator (I'm waiting on the RO membrane until I can replace the sediment and carbon filters, which I will be ordering shortly). I have a line pressure that "fluctuates" between 90 and 94 PSI (I can watch the needle wave back and forth) before the regulator and a fairly steady 64 psi after the first two stages. When I try to close the regulator to reduce the psi much below ~63 psi, the source water line begins to bounce, the pressure gauge goes nuts and I can hear a thumping sound that reminds me of a slow version of a WWII era machine gun. I figure I have multiple issues going on, but I'm at a loss for making this work so I don't have to turn the water on every time I want to get a drink of water (it wouldn't be a problem if it weren't for the drinking water aspect of the setup).

In regard to the physical setup of the filter unit, the source water line is only a few feel long. The water source is the cold water valve for the kitchen sink (the valve has a threaded output for 1/4" hose), so there is plenty of volume. The filter is pretty much stock as far as the internal plumbing goes. The drinking water output Ts off after the storage tank. The two runs go to the sink RO faucet that came with the unit and the other runs around the kitchen to the ice-maker/water dispenser of the refrigerator. All plumbing is 1/4". I have in-line valves on the input and all output lines (for "flood control" when I'm working on the system).

Main questions/concerns:
How do I get the filter to shut off/pressure balance/whatever you call it so I'm not dumping water 24/7 or having to manually control the input water? Is this even a reasonable expectation, or am I off in left field among the dandy lions?
Do I need to change anything in order to replace my 100 gpd RO membrane with a 75 gpd membrane?

Bonus questions:
How do I stop the machine gun?
Do I need to worry about getting my line pressure below 60 psi?

Thanks!

[BuckeyeHydro]

Let me take a shot at each of your questions and give you another comment or two.


Just over five years ago I purchased a Buckeye 100 gpd Reff/Residential RO/DI. I have used it daily since then for my reef and/or for drinking water. It has served my family very well. However, it never shuts off. It used to shut off (most of the time at least) when I lived in an apartment with water pressure closer to ~43 PSI, but the last 3.5 years I have been in a house with ~90 PSI line pressure and it never stops. In an effort to get the system to shut off when the storage tank is full, I pulled the tank to check the water pressure. As soon as I hit the Schrader valve, water came out. :( I ordered a new tank, pressure regulator, pressure gauge kit and a 75 gpd RO membrane (figured I was way overdue to for a replacement) on Monday night based on the assumption that my line pressure is too high and broke the membrane in my storage tank. The parts arrived today and I installed the tank, regulator and pressure gauge with the gauge in-line before the regulator (I'm waiting on the RO membrane until I can replace the sediment and carbon filters, which I will be ordering shortly). I have a line pressure that "fluctuates" between 90 and 94 PSI (I can watch the needle wave back and forth) before the regulator and a fairly steady 64 psi after the first two stages.

Do you actually have one of our pressure regulators controlling pressure in the feedwater line?
http://i224.photobucket.com/albums/dd293/BuckeyeFS/pressureregulator.gif (http://s224.photobucket.com/user/BuckeyeFS/media/pressureregulator.gif.html)




When I try to close the regulator to reduce the psi much below ~63 psi, the source water line begins to bounce, the pressure gauge goes nuts and I can hear a thumping sound that reminds me of a slow version of a WWII era machine gun. I figure I have multiple issues going on, but I'm at a loss for making this work so I don't have to turn the water on every time I want to get a drink of water (it wouldn't be a problem if it weren't for the drinking water aspect of the setup).

Just dial it down to 80 psi.


How do I get the filter to shut off/pressure balance/whatever you call it so I'm not dumping water 24/7 or having to manually control the input water? Is this even a reasonable expectation, or am I off in left field among the dandy lions?
When an ASOV no longer shuts off, it is typically one of these three things:
1. Check valve between permeate port and low pressure "in" port on the ASOV has failed.
2. Float valve on the DI output is leaking (even just a very little bit).
3. The ASOV itself needs to be replaced.


Do I need to change anything in order to replace my 100 gpd RO membrane with a 75 gpd membrane?
I'd sanitize the system if you've never done that. Take the opportunity to lube all the orings. You'll need to replace your capillary flow restrictor with BFS-217 Capillary flow restrictor, pre-trimmed for 75 gpd - $4.00



How do I stop the machine gun?
You won't have this issue to solve as you are only reducing the pressure to 80 psi


Do I need to worry about getting my line pressure below 60 psi?
Nope. Many people buy booster pumps to get their pressure OVER 60 psi.

Russ

[Rychek]

Do you actually have one of our pressure regulators controlling pressure in the feedwater line?
http://i224.photobucket.com/albums/dd293/BuckeyeFS/pressureregulator.gif (http://s224.photobucket.com/user/BuckeyeFS/media/pressureregulator.gif.html)


Yes. It doesn't look exactly like that, but I ordered all of the aforementioned parts directly from Buckeye (Item# 325, per my invoice).





Just dial it down to 80 psi.


That makes it easy. I'll definitely do that.



When an ASOV no longer shuts off, it is typically one of these three things:
1. Check valve between permeate port and low pressure "in" port on the ASOV has failed.
2. Float valve on the DI output is leaking (even just a very little bit).
3. The ASOV itself needs to be replaced.

I'll try to remove the ASOV and open it up. I'm not sure I'll recognize a problem if I see it, but I'll give it a shot. Worst case I replace it, but I have to order new filter elements anyway, so no biggie. Do you have plumbing diagram for how the ASOV should be plumbed?



I'd sanitize the system if you've never done that. Take the opportunity to lube all the orings. You'll need to replace your capillary flow restrictor with BFS-217 Capillary flow restrictor, pre-trimmed for 75 gpd - $4.00

How should I go about sanitizing the system? remove filters and run hot water or bleach through it? boil it? Something else entirely?



Nope. Many people buy booster pumps to get their pressure OVER 60 psi.


I didn't think lowering the pressure would be necessary, but I'm feeling a little paranoid about high pressure due to ruining my storage tank last time.

[BuckeyeHydro]

I'll try to remove the ASOV and open it up. I'm not sure I'll recognize a problem if I see it, but I'll give it a shot. Worst case I replace it, but I have to order new filter elements anyway, so no biggie. Do you have plumbing diagram for how the ASOV should be plumbed?
The ASOV comes with a detailed set of instructions. Here's one of the plumbing diagrams included with the instructions:

http://i224.photobucket.com/albums/dd293/BuckeyeFS/Instructions/RODIwithASOV.jpg (http://s224.photobucket.com/user/BuckeyeFS/media/Instructions/RODIwithASOV.jpg.html)




How should I go about sanitizing the system? remove filters and run hot water or bleach through it? boil it? Something else entirely?


http://i224.photobucket.com/albums/dd293/BuckeyeFS/Instructions/Sanitize.jpg (http://s224.photobucket.com/user/BuckeyeFS/media/Instructions/Sanitize.jpg.html)


I didn't think lowering the pressure would be necessary, but I'm feeling a little paranoid about high pressure due to ruining my storage tank last time.
It's not a given that your pressure caused the tank failure. Those tank bladders don't last forever, regardless of the pressure...

Russ

[Rychek]

Thanks for the info Russ!

I removed and disassembled the ASOV this morning and it looked ok. That is to say, I couldn't identify any obvious damage or malfunction inside. That having been said, I ordered a new ASOV. Then it occurred to me that I hadn't checked the check-valve, so I ordered one of those too, as well as the flow restrictor and two sets of 1 micron sediment filters and 2 carbon blocks. I threw in a new GAC/Odor remover as well, since I'm drinking this water. All in all, I probably could have purchased a new basic RO unit for less, but I should be set once it all arrives. :) Although, after five years of use, I'm a bit hesitant to drink the water coming out of the filter. Though it probably isn't any worse than the tap water. :D

Thanks again!

[Rychek]

I pulled both check-valves from my unit and did a blow test. One let air through only in one direction while the other wouldn't let air in in either direction. However, water must be getting through it. I swapped their positions to see if it had any effect, but it hasn't appeared to change anything.

[BuckeyeHydro]

See if you can get water to flow through them in the wrong direction.

[Rychek]

The valve that wouldn't let air through, lets water through in both directions. Not only that, but while I was testing it, it let air through in the correct direction once. Go figure. At any rate, I think I've found my culprit.

[BuckeyeHydro]

Mystery solved - nice detective work!

[Rychek]

Just an update. I replaces the ASOV and one check-valve and the filter is shutting off. I haven't tested it with the pressure tank attached yet (new RO membrane is still flushing), but I'm confident it will work just fine. Thanks all for all of the help with this!

[Rychek]

Well, all was almost well with this project. I attached the pressure tank and it is working much better than it did before. However, it has trouble shutting off. It makes screeching/machine gun noises and the pressure gauge needle goes nuts. I have replaced the ASOV and check valve that feeds it. What could be causing this issue?

[BuckeyeHydro]

Where is the noise coming from? The ASOV?

[Rychek]

Most of it seems to be coming from the pressure valve as the needle slams back and forth. I would expect the sceetching sounds to be coming from the ASOV, but I haven't pulled the filter out from under the sink to determine what the source is exactly. I'll give it try this afternoon when I have some time.

[BuckeyeHydro]

By pressure valve, I think you mean "pressure gauge," right? Rather than your pressure regulating valve. Let me know what you find...

[Rychek]

Yes, gauge, not valve. I increased the pressure on my regulator to about 83 PSI and the issue has, so far, gone away. If the regulator is set lower much lower, the pressure in the feed line starts to fluctuate and I get a machine gun effect and everything starts shaking.