Has anyone had this problem? RO membrane O ring failure?

[MidlandsJohn]

I'll state the facts and the problem first, then my theory. Hopefully some of you might weigh in with some experience.

Been using a Brodex system for 10 years, so not a novice.

For about 6 months my resin has not been lasting as long as normal, so a month ago I changed the main RO membrane. They normally last about 2 years, but this time it was only about 18 months old. Weird, I thought. Of course, I changed the resin and the sediment filter at the same time.

Now, a month later my resin is dead again. Resin refill used to last up to 4 months (we are in a very hard water area).

The TDS reading a week ago was zero. Now its 60. How can the new membrane be chucking out such dirty water, I wondered?

I can keep changing resin to keep working, but its expensive, and something is definitely wrong here.

My theory is this.... I believe the O-rings, which sit inside the RO housing end-cap, sealing around the output nozzle on the end of the membrane have gone hard, and lost the ability to seal.

Therefore I believe that drain water is leaking into my output, along with clean water from the membrane, and all going into the resin vessel, which purifies the mixture, thus causing the resin to work harder, and thus become dead sooner. Once the resin is done, it's done, and the TDS shoots up to 60 odd, which is condition of the mixture coming out of the RO housing (clean water plus the drain water leaking past the O rings.

If any of you can get your brain around this, I'd love to hear what you think.

I have new O rings on order, but at this point I cannot know if I'm on the right track.

 

[Iron Giant]

@spruce is the man

 

[Part Timer]

Have you checked the TDS out of the R/O before it goes into the DI? Has your water pressure dropped recently?

 

[spruce]

I'll state the facts and the problem first, then my theory. Hopefully some of you might weigh in with some experience.

Been using a Brodex system for 10 years, so not a novice.

For about 6 months my resin has not been lasting as long as normal, so a month ago I changed the main RO membrane. They normally last about 2 years, but this time it was only about 18 months old. Weird, I thought. Of course, I changed the resin and the sediment filter at the same time.

Now, a month later my resin is dead again. Resin refill used to last up to 4 months (we are in a very hard water area).

The TDS reading a week ago was zero. Now its 60. How can the new membrane be chucking out such dirty water, I wondered?

I can keep changing resin to keep working, but its expensive, and something is definitely wrong here.

My theory is this.... I believe the O-rings, which sit inside the RO housing end-cap, sealing around the output nozzle on the end of the membrane have gone hard, and lost the ability to seal.

Therefore I believe that drain water is leaking into my output, along with clean water from the membrane, and all going into the resin vessel, which purifies the mixture, thus causing the resin to work harder, and thus become dead sooner. Once the resin is done, it's done, and the TDS shoots up to 60 odd, which is condition of the mixture coming out of the RO housing (clean water plus the drain water leaking past the O rings.

If any of you can get your brain around this, I'd love to hear what you think.

I have new O rings on order, but at this point I cannot know if I'm on the right track.

This is probably a question for @doug atkinson.

As with a lot of things, finding a solution to an issue usually means identifying a suspect area and then testing it to see if the issue goes away.

You have ordered replacement o rings so fit those first and see if that solves the problem.

The brine seal on the membrane also plays an important part so you need to check that that is seated properly and that the housing has a clean surface for that seal to seal against.

My gut is pointing me in the direction of the membrane.

Whose membrane did you fit?

What prefilter are you fitting?

Brodex only used to supply a single prefilter on their systems. They fitted a sediment filter in it as they didn't believe that chlorine is an issue in our water supply. This belief is strange, as every other supplier believes that their system must have a carbon block filter to remove chlorine. Chlorine eats away membrane material. This is why most of us have 2 prefilter housings, one for a sediment filter and the other for a carbon filter.

If you have a single prefilter and your water is sediment free then you could use a Fiberdyne carbon block 5 micron filter only which would act as a sediment filter as well.

 

[spruce]

Have you checked the TDS out of the R/O before it goes into the DI? Has your water pressure dropped recently?

His tds before di is 60ppm which is why he is using so much resin.

 

[Part Timer]

His tds before di is 60ppm which is why he is using so much resin.

Bit early on a Monday for me, thought he said after DI

 

[MidlandsJohn]

I get my supplies from Doug at Daqua. Membrane is Axeon HF5. Resin is Tulsion MB115. 10" Carbon prefilter.

I have only tested the TDS after DI, but considering the resin is totally shot, we can assume the TDS reading may as well be pre-DI (the resin is doing nothing)

 

[spruce]

I'll state the facts and the problem first, then my theory. Hopefully some of you might weigh in with some experience.

Been using a Brodex system for 10 years, so not a novice.

For about 6 months my resin has not been lasting as long as normal, so a month ago I changed the main RO membrane. They normally last about 2 years, but this time it was only about 18 months old. Weird, I thought. Of course, I changed the resin and the sediment filter at the same time.

Now, a month later my resin is dead again. Resin refill used to last up to 4 months (we are in a very hard water area).

The TDS reading a week ago was zero. Now its 60. How can the new membrane be chucking out such dirty water, I wondered?

I can keep changing resin to keep working, but its expensive, and something is definitely wrong here.

My theory is this.... I believe the O-rings, which sit inside the RO housing end-cap, sealing around the output nozzle on the end of the membrane have gone hard, and lost the ability to seal.

Therefore I believe that drain water is leaking into my output, along with clean water from the membrane, and all going into the resin vessel, which purifies the mixture, thus causing the resin to work harder, and thus become dead sooner. Once the resin is done, it's done, and the TDS shoots up to 60 odd, which is condition of the mixture coming out of the RO housing (clean water plus the drain water leaking past the O rings.

If any of you can get your brain around this, I'd love to hear what you think.

I have new O rings on order, but at this point I cannot know if I'm on the right track.

When assembling the membrane, we had to lubricate the o rings with the grease provided when I purchased the housing.

I have always used a very thin smear of Vaseline on the o rings but recently purchased and used some WRAS approved silicone grease on the seal on my tank lid.

https://www.ebay.co.uk/itm/293268497348

My 4040 membrane is now 8 years old and still performing at a rejection rate of 97%. Granted, our water is soft to medium; around 130ppm.

Its an Axeon HF5 membrane.

Snap ring A O Ring installation.pdf rokit.pdf

 

[doug atkinson]

With Brodex systems I tend to find they have not been set up right waste to pure ratio. Past experience less waste than pure which means that if kills off your membrane quickly and high ppm. 
 

You need to measure the ppm going into the DI Vessel, then measure how long to fill a litre jug pure and waste.

I know this can be hard as they seem to configure systems differently. It can be R/O into tank then tank to pump to DI Vessel. Or R/O to DI to tank.

One of the most common things that go on Brodex machines is the washer which they use to create back pressure. It usually rusts away as not made of SS.

 

[MidlandsJohn]

Hi Doug, thanks for showing up.

Forget the DI vessel for now, Not being funny, but its not part of this problem. Consider the DI vessel to be empty. I'm getting TDS of 60+.

Somehow a small amount of drain water is finding its way past/around the membrane, and burning up my resin real quick.

The only explanation I can think of is the O ring has gone hard after 11 years, and it is allowing drain water through, along with the clean water, into the DI vessel. Hence the output mixture from the RO being at TDS 60.

The O ring has had about 6 membrane changes in 11 years, so it wouldn't be surprising if it is no longer sealing.

I wondered if its something anyone else has experienced. The replacements arrive tomorrow or Wed, so I'll report back if it fixes the problem.

At the moment, I have no choice but to rely on the DI to clean the water, so I can earn.

By the way, the Brodex I have has an adjustable drain valve/gauge on the side of the tank, so I can see how much drain versus how much product I'm making. I flush (fully open valve) every day before filling, and I fill at around 2ltrs drain to 1.25 ltrs pure. We have very hard water, around 290 TDS from the tap.

 

[doug atkinson]

Hi Doug, thanks for showing up.

Forget the DI vessel for now, Not being funny, but its not part of this problem. Consider the DI vessel to be empty. I'm getting TDS of 60+.

Somehow a small amount of drain water is finding its way past/around the membrane, and burning up my resin real quick.

The only explanation I can think of is the O ring has gone hard after 11 years, and it is allowing drain water through, along with the clean water, into the DI vessel. Hence the output mixture from the RO being at TDS 60.

The O ring has had about 6 membrane changes in 11 years, so it wouldn't be surprising if it is no longer sealing.

I wondered if its something anyone else has experienced. The replacements arrive tomorrow or Wed, so I'll report back if it fixes the problem.

At the moment, I have no choice but to rely on the DI to clean the water, so I can earn.

By the way, the Brodex I have has an adjustable drain valve/gauge on the side of the tank, so I can see how much drain versus how much product I'm making. I flush (fully open valve) every day before filling, and I fill at around 2ltrs drain to 1.25 ltrs pure. We have very hard water, around 290 TDS from the tap.

Is it a stainless steel housing or white PVC housing.

 

[MidlandsJohn]

Is it a stainless steel housing or white PVC housing.

Yes, its a stainless steel housing with black plastic end caps.

 

[doug atkinson]

Yes, its a stainless steel housing with black plastic end caps.

I was thinking out of the box if you swapped the end caps round and swapped fittings. It may work but the centre shaft is hollow so could replicate the problem.

 

[MidlandsJohn]

I was thinking out of the box if you swapped the end caps round and swapped fittings. It may work but the centre shaft is hollow so could replicate the problem.

That's an interesting idea, Doug.

I guess you are saying the end caps are reversible (makes sense). Didn't think of that. Not sure if the blank end will have O rings fitted - thats the "Brine seal" end, and has a plastic bung instead of the output port..

I have 5 new O rings arriving any day (£2 from ebay) after digging around to find out what size/material etc. So I'll try that option first as it is the easiest to do.

I see that replacement end caps (identical) proclaim to have 2 x O rings fitted for extra certainty.

Do you keep stock of O rings (3/4" ID x 3/32" thickness nitrile rubber) or end caps by the way?

 

[spruce]

Hi Doug, thanks for showing up.

Forget the DI vessel for now, Not being funny, but its not part of this problem. Consider the DI vessel to be empty. I'm getting TDS of 60+.

Somehow a small amount of drain water is finding its way past/around the membrane, and burning up my resin real quick.

The only explanation I can think of is the O ring has gone hard after 11 years, and it is allowing drain water through, along with the clean water, into the DI vessel. Hence the output mixture from the RO being at TDS 60.

The O ring has had about 6 membrane changes in 11 years, so it wouldn't be surprising if it is no longer sealing.

I wondered if its something anyone else has experienced. The replacements arrive tomorrow or Wed, so I'll report back if it fixes the problem.

At the moment, I have no choice but to rely on the DI to clean the water, so I can earn.

By the way, the Brodex I have has an adjustable drain valve/gauge on the side of the tank, so I can see how much drain versus how much product I'm making. I flush (fully open valve) every day before filling, and I fill at around 2ltrs drain to 1.25 ltrs pure. We have very hard water, around 290 TDS from the tap.

If you think your water it's very hard, please think of the poor window cleaners in Hartlepool. ? Their water out of the tap is 550ppm last time we heard. 

 

[MidlandsJohn]

If you think your water it's very hard, please think of the poor window cleaners in Hartlepool. ? Their water out of the tap is 550ppm last time we heard. 

Seriously? Thats crazy. Ours used to be 350 ish, but it's come down a bit (I'm in Warwick - Severn Trent Water - not sure where the water comes from though)

I won't even drink our tap water. What with all the fluoride and stuff in it, it tastes horrible.

 

[Iron Giant]

If you think your water it's very hard, please think of the poor window cleaners in Hartlepool. ? Their water out of the tap is 550ppm last time we heard. 

The tap water in Hartlepool tastes lovely ?

 

[MidlandsJohn]

So ... quick update as promised.

O-Rings arrived today so as it was raining I disassembled the RO intending to swap O-rings only to discover that the ones specified are smaller than the ones fitted in the end caps from China.

So, thanks to Doug@Daqua I left them fitted, and swapped over the end caps, as they are identical. The input end simply has a blanking plug fitted instead of the clean water output. Easy to swap over.

The result is that the output from the RO is now TDS 33 from tap water reading 310 today.

This means the RO is removing about 90% of the TDS.

Not perfect, but a big improvement on the 60+ reading before I swapped the end caps.

Conclusion is that the O ring on the other end is also old and hard, but better than its partner.

I have ordered a new end cap from ebay for £13, and to be safe, I have ordered 5 more O-rings, this time of the correct size.

My resin should last twice as long for now, and I'll update here when I have replaced the end cap in a few days.

Hope this has all been of some use to people now or in future.

Bloody O rings!!!

 

[Part Timer]

You got there in the end but still think I'd be buying a new Membrane.

 

[doug atkinson]

Thanks for sharing. I did come across an issue and too ages to find it. It was a hair line crack but not visible in normal light. Only found when using a bright light.