Strange plumbing issue and RO unit

[chunkoblue]

Hi, I'm having a strange issue regarding my new setup for my RO unit. We have a spare shower that does not get used, so I decided to install my RO unit in the shower so I didn't have to constantly connect/disconnect it from my bathroom sink. Here is what I did. I removed the shower head, and replaced it with a 1/2 sillcock valve, and attached the RO unit. The valve for the shower is the kind that is a knob that can be turned all the way to the left for hot water, and all the way right for cold water. There are no leaks, and the RO unit is functioning just fine, but there is one weird issue.
Before I did this, and the shower head was attached, the knob had to be turned almost all the way to the left (hot) for it to be warm enough to shower with. Now, with the RO unit attached, I have the knob all the way to the right (cold) and the water eventually comes out very warm. Not so hot that you couldn't wash your hands with it, but on the warmer side of what is comfortable to wash your hands with. So this raises a few questions:

1. Anybody have any idea why the water would be coming out warm when the knob is set all the way to cold?
2. Is this going to harm my membrane if I let it go through warm, but not hot?

I have found that it takes about 30 minutes to get up in temperature, so I have been running the unit 30 minutes at a time and letting the pipes cool down between uses, but I really would like to leave it running longer. I have thought maybe attaching a long hose between the adapter and RO unit might allow some of the heat dissipate before getting to the unit, but am not sure that would work either. Any ideas?

 

[SubRosa]

It likely has to do with the added backpressure that the valve is subjected to. It's not designed for it. RO systems are generally rated with water @ 70F. Cooler temps reduce production, and higher temps can definitely damage the membrane. You could turn off the hot water supply to the shower.

 

[TL1000RSquid]

I believe they say the ideal temp water to run through a RO unit is around 58-60 degrees. Warmer water might maybe shave a couple months off the membranes life but I don't think it will shorten it significantly.

 

[chunkoblue]

I read online that damage generally occurs at 95 degrees F and up. I can't really tell what the temp is by the time it gets to the membrane, but I imagine it around 95. Maybe I will try attaching a hose to the sillcock and coil about 20 feet of it inside a bucket, then attach the hose to the RO unit. I can have the waste water fill the bucket so incoming water will lose some heat to the waste water filling the bucket. This probably won't work for long periods of time, but should buy me some extra time..

Also, if I throw a thermometer in the bucket I can get an idea within a few degrees of the temperature of the water entering the membrane.

I would turn the hot water of to the shower if I know where to do it, but I recently moved into thiis condo, and I don't know where a shutoff valve for the shower would be, if I even have access to it..

 

[chunkoblue]

Also, if the sillcock valve is causing back pressure perhaps causing more hot water and less cold water to come from the shower knob, would the following adapter be a better choice?

http://www.amazon.com/Anderson-Meta...8-2&keywords=1/2"+female+to+3/4"+male+adapter

 

[Rev_Jim_Jones]

The Back Pressure is Coming from the RO Unit not the Hose bib, Best bet is jut to turn the hot water off to that Shower.

 

[dudley]

I would say the problem is related to the shower handle valve and not the R.O. unit. It's possible that the cartridge valve located below the handle is worn and causing hot water to migrate over to the cold water side and probably also the cold to hot side since you noticed an issue with getting sufficiently hot water from the original setup.

Or the previous owner adjusted the valve to avoid scalding issues. It's relatively easy to check or repair the valve by removing the cap on the knob, the center screw and then the knob. Also the silver faceplate will remove and this will allow you to see whether you have shut off valves in the wall.

 

[chunkoblue]

I would say the problem is related to the shower handle valve and not the R.O. unit. It's possible that the cartridge valve located below the handle is worn and causing hot water to migrate over to the cold water side and probably also the cold to hot side since you noticed an issue with getting sufficiently hot water from the original setup.

Or the previous owner adjusted the valve to avoid scalding issues. It's relatively easy to check or repair the valve by removing the cap on the knob, the center screw and then the knob. Also the silver faceplate will remove and this will allow you to see whether you have shut off valves in the wall.

Thank you so much dudley! I removed the knob, made some adjustments and now it runs cold when set to cold, and hot when set to hot. You made my day!

 

[SubRosa]

I read online that damage generally occurs at 95 degrees F and up. I can't really tell what the temp is by the time it gets to the membrane, but I imagine it around 95. Maybe I will try attaching a hose to the sillcock and coil about 20 feet of it inside a bucket, then attach the hose to the RO unit. I can have the waste water fill the bucket so incoming water will lose some heat to the waste water filling the bucket. This probably won't work for long periods of time, but should buy me some extra time..

Also, if I throw a thermometer in the bucket I can get an idea within a few degrees of the temperature of the water entering the membrane.

I would turn the hot water of to the shower if I know where to do it, but I recently moved into thiis condo, and I don't know where a shutoff valve for the shower would be, if I even have access to it..

If the building is anywhere near current on code you have to have access to it. There's likely an access panel on a wall outside the bathroom, most likely directly behind the shower head itself. They're often in closets.

 

[dudley]

Thank you so much dudley! I removed the knob, made some adjustments and now it runs cold when set to cold, and hot when set to hot. You made my day!

Glad I could help and that it was an easy fix.