Water Softeners and Air Filtration Systems - GE Merlin RO won't shut off reliably.

Ok, this thing is giving me fits. The vendor it was bought from is out of state and no longer sells or supports the unit. GE refers me to a local vendor - whom I didn't buy the unit from, we'll see if they will help.

The issue is that it runs continuously. Sometimes a .6gal/min, sometimes a fairly slow leak out of the waste water line.
It's configured differently than OEM as the faucet is *not* an air gap faucet. The OEM faucet will not work in our thickness of counter and GE doesn't provide an alternate solution.

We've tried replacing all 3 filters (about $250) - making sure they were properly seated, allowing the air to bleed out of the system.
Occasionally the system will not leak and will function properly, but I find myself manually shutting off the water as over a week, it will go through 1000 gallons or more if not shut off.

How do the valves in the manifold system work to cut off water flow?
Our input pressure varies from 40-70psi (well water).
Measured pressure on the faucet varies from about 5psi (leaking waste water) to 20 psi (unit shuts off). The faucet itself has no leaks of any kind.

I've considered pressure sensitive switches to turn off the incoming water, but faucet pressure isn't high enough to trigger many of them.

GE says to not use this unit with a pressure tank, except for the backflush tank/port.

I can replace the manifold on this system ($125) - but if I don't have a good chance of fixing it, I don't want to do that... Can anyone explain how these systems shut off mechanically and if there are any issues going from airgap to non-airgap faucet (the unit should support either). I'm about ready to toss this thing and it wasn't inexpensive.

The auto shut off works on both inline (feed water) pressure and ro tank pressure. When the tank pressure drops below inline pressure, the auto shut will allow inline water to pass through the membrane. Once the tank pressure is strong enough, it shut the feed water. To test the shut off, simply turn off the tank valve. This will represent a full tank and within 5 mins, the feed water should shut off.

The GE Merlin is a "tankless" unit. GE says specifically not to use a pressure tank with the unit as it will cause "damage"... The units that are setup with a tank use an atmospheric pressure tank and a float.

I can tell you that my faucet pressure usually doesn't reach my line pressure. The unit seems to be leaking water internally - I get about 5-10 psi registering at the faucet, the unit is leaking. If I can get the faucet up to 20 psi or so, usually by manipulating the faucet on/off, then the unit appears to stop leaking.

Am I correct to assume that this is a manifold issue?

I didn't know it was a tankless unit. I looked up the specs but could not find any repair advise. Yes, the auto shut off has to be in the manifold but it did not show how to get to it. I worked in Round Rock for 13 yrs in the water treatment industry. You might try Tommy Dorsey Water Conditioning. He's been doing water treatment in your area for over 30 years.

I didn't know it was a tankless unit. I looked up the specs but could not find any repair advise. I worked in Round Rock for 13 yrs in the water treatment industry. You might try Tommy Dorsey Water Conditioning. He's been doing water treatment in your area for over 30 years.

I'm familiar with Tommy Dorsey - that's a good recommendation.
I'm a DIYer. Tommy has done several of my neighbors systems - I've copied his implementations at about 1/2 of the price.
Also, he's not a "dealer/retailer" for GE. I'm sure he can sell me a great RO unit, but I'd rather have advice on this one before I decide to kick it out the door...
Hopefully a GE dealer will respond.

LOL. He taught me the business about 19 years ago. I am a authorized GE service tech. I'll call them tomorrow and ask some questions. I'm always wanting to learn and if I can help, it would be my pleasure. Can you give me the model number? I know they will ask for it.

I'd sincerely appreciate it.
The model is "GE Merlin" - I can't find a number on the manifold or the filter covers anywhere... I believe there was a model number on a sticker at one time, but it's long since been washed way when changing filters.

What I'd tell them:
1) I've got a non-airgap faucet (this should be supported)
2) Variable water feed pressure 40-70psi
3) Water pressure at the faucet is varying from 5-20psi. When the faucet pressure is low, I hear water running in the wastewater line. The faucet doesn't leak. We get the best shut off when we have higher pressure in the faucet line.

All 3 filters were changed recently - the unit leaked prior to the filter change. They've also been removed and were checked to make sure that the o-rings were properly seated in the manifold.

Basically I suspect a bad manifold, but I don't want to drop another dime on this thing until I can confirm that diagnosis with GE - or someone else who has experienced the same thing.

Man, I'd really appreciate some support from a GE dealer as GE won't talk to me directly... I've seen a lot of dealers have dropped support of this product, I just wish I knew why.

I've seen a lot of dealers have dropped support of this product, I just wish I knew why.

Most likely because of poor preformance or repeated service calls. I called GE and the first thing they asked was for a model number. I told them I didn't have one and explained the RO and the fact that it does not have a pressure tank. He told me he had never heard of an RO without a tank. Tells me all he is going to do is look in a manual. I can do that if I can find one. I've sent you a pm with my phone number. Call me.

I'll call you - Manuals can be found here:
http://www.freshwatersystems.com/support/MerlinBrochure%5B1%5D.pdf

http://www.freshwatersystems.com/support/MerlinPhotoSpread%5B1%5D.pdf

http://www.freshwatersystems.com/specifications/MerlinInstallManual.pdf

http://www.freshwatersystems.com/products/specifications/MerlinSpecsnPerf.pdf

Description: WATER TREATMENT DEVICE-REVERSE OSMOSIS
Manufacturer: GE INFRASTRUCTURE WATER & PROCESS TECH.
Product Name: MERLIN
Model Number(s): MERLIN I AND MERLIN II
Product File No: 20040642

Aquatec Permeate Pump (http://www.pwgazette.com/permeatepump.htm)
This is the permeate pump I was talking about. You must disable the auto shut off for this system to work.
I called GE again and was told without a model # (Merlin 1 or 2 is not a model #) there is nothing they can do. One of the sites you sent me had a phone #. I called it to talk with a svc tech. Left a message and am waiting for a return call. I'll keep you posted.
BTW, having a non air gap faucet does not matter.

You're having about as much luck with GE as I did.
GE's website lists the manual for the thing - no model number is mentioned:
http://www.gewater.com/pdf/resdntl/manuals/1262366_Rev_G_Merlin_Owners_Manual.pdf

The only other things I can find are through certification:
Product Name: MERLIN
Model Number(s): 20040642
Product File No: 20040642

I believe the Model number here is internal to the guys doing the certification... I *know* GE knows about these things - they spent millions marketing the unit.

They guys that are referenced as selling them to dealers:
North American Sales
5730 N. Glen Park Road
(262) 238-4400 Phone

I was able to talk with someone who knows about this unit. He said 1 of 4 things will cause it to run to the drain.
1. The prefilter is clogged. Take out the prefilter and run system (no longer than 10 min). If it shuts off, the prefilter is clogged.
2. In line pressure is too low. Must have 40 psi mim. With pressure switch set at 60/40 you might be getting less than 40at the unit. Raise pressure switch to 70/50
3. If ice maker is hooked up to the unit, it may be pulling pressure from outlet side. Connect a shut off valve on ice maker line a see if it will stop the drain from running.
4. Replace the manifold. You can not get to the auto shut off in the manifold.
Hope this helps.

Thanks - that helps.
Question:
1) By prefilter does he mean the carbon filter that's before the two permeate/membranes? In the standard implementation, there is no filter of any type before the RO unit itself (carbon -> membrane -> membrane). Note - all 3 were replaced recently.. I can try it without the carbon.

My well switch seems to be adjustable only on the high side. I can replace it with a 50psi min setup.

Ice maker is hooked up. I've tested it disconnected (and have been leaving it disconnected) - this isn't changing anything.

Manifold is next after moving the baseline pressure up on the pump.... Thanks.

Thanks - that helps.
Question:
1) By prefilter does he mean the carbon filter that's before the two permeate/membranes? In the standard implementation, there is no filter of any type before the RO unit itself (carbon -> membrane -> membrane). Note - all 3 were replaced recently.. I can try it without the carbon.

My well switch seems to be adjustable only on the high side. I can replace it with a 50psi min setup. Ice maker is hooked up. I've tested it disconnected (and have been leaving it disconnected) - this isn't changing anything.

Manifold is next after moving the baseline pressure up on the pump.... Thanks.

Yes. The carbon filter is the prefilter. Do you have 2 posts (adjusting screws) on your pressure switch? The taller (bigger nut) is the cut on/cut off adjustment. Using a 3/8 nut driver, turn it clockwise to increase the pressure. I believe 4 turns = 1 lb. Make sure the pressure gauges works. Turn the adjusting screw then push down the the plate below it. The pump will come on until it reaches the set pressure. I believe your problem is lack of pressure. You have said you can get it to turn off. That tells me it is working. When I found out it requires a min of 40 lbs and your pressure switch is set to 40 lbs, it makes sense.

Pressure switch - I have two nuts, but they basically are a rough and fine adjustment of pre-load on a spring... They adjust cut off pressure only.

The smaller one is a differential adjustment. The difference between the cut on and cut off. Normally it is set for 20 lbs. Hence 60/40 or 70/50. I don't reccomend you adjust it. The taller one will raise or lower the cut on/ cut off.