TMC V2 Pure 50 RO System + DI Unit with Bypass

[X3NiTH]

I plumbed in the V2 Pure 50 RO unit under my sink this weekend and installed a tap next to my sink to draw the water. This is my first experience of plumbing in and using a RO System and I was hoping to have done everything correctly with the installation? I'm no stranger to plumbing and can competently bend/plumb/solder copper, so I am fairly confident I have it plumbed in correctly.The System doesn't come with a DI unit so I had to order this separately along with 4 valves and 2 T-Pieces, the extra connectors were to plumb a bypass line so I can extend the life of the DI unit when doing a system flush post cartridge change. The below image shows how the bypass line is plumbed in.

http://farm4.staticflickr.com/3668/14104585637_d8850f2f80_b.jpg

I have a valve just before the water inlet to the RO unit so I can isolate the system from the 'clamp kit' mains feeder line when doing a cartridge change without having to disturb the tap on the clamp or turns the mains water off. I have plumbed in the TDS/Out probe after the bypass so that I can measure the TDS of the output water before or after the DI unit depending on the state of the bypass.

I have a question about its normal operating parameters -

Does this RO system when correctly installed continually run waste water down the drain even when you are NOT drawing the filtered water from the tap ?

If this is correct its not a huge problem as I am not on a water meter but I don't want to waste water unnecessarily, so in order not to waste water should I use the tap before the system to stop waste water flow when I'm not drawing from the tap or should I plumb another valve on the waste line and use that if there were a need to keep the system pressurised. Talking of pressure, my mains pressure on the unit is reading 40psi which is below the recommended value for optimal efficiency so I am only getting about 22gpd out instead of the potential 50gpd, but this is still way more than enough for my needs, I just hope that the low pressure hasn't anything to do with the constant waste flow but then again if it does require more pressure I can always stick a pump before the system to get the pressure up from the mains.

So, if anyone has any experience of this unit, have I done it right?

 

[ian_m]

You need to fit an auto shutoff valve on the inlet to cut off water supply when there is not output flow. You can't leave it running 24/7 (obviously water waste) as it will quickly exhaust your carbon filter, start letting chlorine/chloramine through and then ruin the membrane.

You need one of these.
Auto Shutoff Pressure Valve - Osmotics Water Filtration

Also might want to consider a booster pump to run the unit at optimum pressure, as most RO units give their working output (yours 50gpd) at usually 6 bar pressure. As you are running yours at 2.7bar (40psi) you will get less than 1/2 the output (50 * 2.7/6 -> 22.5 gpd). At reduced pressure there can also be an increase in waste water ratio to sometimes even 10:1. Thus 1litre of RO water @ 2.7bar uses 11l of water -> £3.50 @ 11/1000 -> 4 pence per litre (Southern water prices). At 6bar uses 5l of water (assuming 4:1 ratio) -> 1.7 pence per litre, thus 1/2 the price.

http://www.osmotics.co.uk/products/...ster-Pump-for-36gpd-to-150gpd-RO-Systems.html

Oh I nearly forgot, you need to inform your water board you have connected a RO system (item d). It is quite a serious offence to contaminate the water supply, if you accidently pump waste water into the mains due to incorrectly fitting something.

Notification form guidance notes

I did it when I fitted my water softener, they just replied with an OK. They where mainly interested that a double check valve had been fitted to the incoming mains supply to stop reverse contamination of the mains

 

[X3NiTH]

Thanks for the detailed response Ian!

Funnily enough when I was researching the behaviour of this unit a malfunctioning ASPV was one of two things that explained what I was experiencing, the other being a broken check valve, I went as far as watching a video on Youtube showing the dismantling of an ASO (US acronymical descriptive of ASPV) to clear any debris blockage to regain functionality of the unit. I then scoured the V2 manual for said part and found no ASPV and no check valve either, this prompted my post to confirm the units behaviour. You know it would have been really nice if TMC had supplied all of this information as a leaflet of some sort within the box, especially the part of having to inform your local water authority.

It's very good information to know that the use of a double check valve before the RO draw point was the necessary piece of the puzzle you needed to have installed to achieve regulatory compliance.

As I live in Scotland I have found the necessary notifications of regulations for 2014 here - Bylaws and the form that needs filling in here - Water Bylaws Notification Form.

At the end of the Notification Form is this little nugget -

Please ensure that you send a hard copy of the plan of premises to which the proposal relates and a schematic diagram showing pipe work, terminal fittings and backflow prevention devices to be installed to:

Thats pretty much a night in front of sketchup then to describe my little slice of Tenement and either a retrospective photograph or back of an envelope scribble of the pipe fittings to submit. Obviously I'll need to source an ASPV, difficult to get locally so I will have to order that online, but the all important Double Check Valve, I can get that locally and fit that now to secure the mains for compliance. I have already been looking into the pumps to up the pressure and will probably end up with the D-D RO Booster Pump, other domestic RO pumps I had looked at were 1 hour of continuous operation with 2 hours rest which would be a pain to use, the Aquarium Solutions pump has a much better cycle time of 4 hours continuous use with a 15 minutes rest period, this should mean I can fill a 25L Jerry Can with my 50gpd unit in one go, (theoretically)!

Again, many thanks!

 

[ian_m]

When I fitted my double check valve I also added (as I had the room under the kitchen sink) a full bore quarter turn ball valve straight after the main incoming stop cock. This means I can easily turn the water off without, in my case, having to reach under the kitchen units to get to the mains stop cock.

Of course if you are fitting a booster pump and ASPV you could pipe the RO water to a container with a ball valve fitted. Thus before you need your RO water (night before ?), you turn the RO output valve on, water flows, pump pumps until the ball valve fitted to your RO storage container stops the flow as storage container full. Job done, zero intervention by you.....

And....

Put a 100W (?) heater in your storage tank and you can pre-warm your RO water as well....

Put a RO ball valve 50% way up in your tank and another on mains water at top, thus fill to 50% with RO and then top up to 100% with tap water for 50:50 RO/tap water.....

And fit a timer and valve to flush the membrane every month.....

 

[X3NiTH]

I may sort the storage later, if and when I can commandeer the remaining space under the sink by finding an alternative home for the pots and pans. D-D pump and ASPV ordered, also a couple of RO hose inline check valves in addition to the 15mm double check valve for the mains under the sink. I take it you mean Float Valves in the storage tank for flow shutoff. The kitchen sink is about 3-4ft from my tank so I could install an RO auto-topoff, or even auto water change, but for the moment I'll stick with getting the basics sorted first and if it that pans out okay, I may try and open negotiations for the upgrades later, maybe.