Wash-it pro... What am I doing wrong?

Each time I try to run the wash-it in RO/DI mode the hose blows off the DI from back pressure. I’ve tried to control it by slightly closing the RO exit valve but that doesn’t work. It’s also always leaked water from the black end cap on the bottom of the RO tank. Any advice from you wash-it owners?

If you don’t get an answer tonite or Sunday call WCR on Monday, Chris or Alex will certainly do their best to solve your dilemma.

Or send an email to John Lee

Hi Brandon

The leaking seal, I will leave to WCR to resolve - we will get advice from IPC - hopefully you can re-apply plumbers tape to seal it.

Re the back-pressure- we can approach it methodically

1/. Waste water must be open and flowing

2/. Check connecting to DI IN

3/. Try running DI ONLY

4/. Try opening the DI HOUSING, removing the canister, re-assemble without the canister and apply normal water pressure

This will determine if the problem is related to the canister.

5/. Remove all hosing to pole and check out of DI - this isolates if the problem is in housing or after it in the hose

6/. Is there anything you use differently with RO-DI compared RO ONLY?

I saw the PM - I will look at that now, also

Perry, ran through your checklist.

1 Waster water always open and running,

2 DI in is under backflow pressure constantly, making the DI drain long unless I need a shower. (It is connected correctly.)

3 Tds readings in my area range from 150-700 so I usually run RO/DI. The source hose connection is secure but again lots of back pressure.

  1. Removing DI canister gave same results.

My pole hose connects to DI out. Have had trouble from start with pressure when using 1/4 polyair hose before pole hose.

DI canister suggests incoming pressure be between 75-85 psi and also suggests installing pressure regulator. Why isn’t one included if it’s needed for consistent performance?

Thanks for the help.

Give us a call tomm when you have a free minute… We should be able to walk you through this with no problem.

It sounds like your hose set-up is causing the resistance.

At TDS 150-170, I would definitely be trying RO ONLY Mode … This should be out under TDS010 - are you doing the weekly DI Flush ?

There is absolutely no need for a Pressure Regulator. We are using universal housings - these would be found anywhere in an industrial application and the rating is there for the guidance of maximums. Some RO Systems are operated at 250PSI and greater.

If you have a problem with no DI Canister in place, it would suggest that there is too much resistance after the DI , not in the DI housing. There is still, of course, a small chance of something being caught in the throat of one of the in/outlets.

Have you read the 21 REASONS - MAXIMUM FLOW DESIGN? How did you end up with 1/4" air hose ? That is the 3 layer braided tube for pneumatic tools, right ?

Lot’s of guys use that size hose to run their poles. What size hose is recommended for wash it? [MENTION=378]Perry Tait[/MENTION]

Yeah I use air hose as well 1/4 and would like to know suggested hose size since I am considering this system.

Still don’t understand the point and hassle of running an RO unit. My DI refills are so cheap and headache free. Typical TDS around my area is 350-450, still get plenty of use out of one tank…

I see so many threads like this… :eek:

If you have a quick scan of the article “21 Reasons to Go Wash-iT PRO” Maximum Flow - you can get the gist of the issues at play here.

I have written an article on pressure losses across systems for the next WCBO magazine (the MASH with WCM) - but the main issues are anything that causes resistance, including centrifugal friction and wall friction.

Wall friction is the one at play here … imagine this - Water moves in layers - a little like clouds in the sky - you can see them moving at different speeds. When water is in a river, the water in the middle travels faster than the water at the banks because the banks cause friction.

The same happens in tubes … the walls of the tube all create friction and slow down the water running against the walls. … the next layer is also slowed down, but not as much …and so on … the fastest water is in the middle. Now if this were a 2ft stormwater pipe, the effect is less significant than a 1/4" tube. The greater the ID ( inside diameter) of a tube, not only the greater the volume, but the less the effect of wall friction.

With this in mind, your long runs should be 3/8" to 1/2" Hose (6-8mm ID) If the 1/4" refers to ID, then this is suitable, but not as good as the 8mm.

Resistance results in a build-up of pressure behind it, and it is cumulative and unable to reverse downstream, so the design of your system is CRITICAL to getting good flow at the brush - without reverting to a pump as a bandaid.

This is an easy one to answer … if you post your annual DI running cost and your cost per cu ft of DI resin, I can give you the maths.

This customer issue is nothing to do with RO or DI ( in fact it is more to do with DI than RO) - it is about the dynamics of his set-up … something is blocked and causing a back pressure.

Did you go ahead with one, Mark ?

While i’ve done my math, I’d be interested in seeing your math too,

I pay $65 for 450-600 gallons

I do see how the sediment and carbon take the load off the resin instead of using “resin power” for easily removed gunk

I pay $40 for a swap out [MENTION=1377]Bruce[/MENTION], now take the cost of an RO unit + filter replacements and annoyance of use… Ill stick to my DI :slight_smile:

$40? woo hoo! that is cheap

I am an ex-DI user x 2 and RO (RHG5) user x 2 units.

With this in mind, I think I can be even-handed in the way I recommend solutions. The key is always the balance of convenience and cost.

$40 is a cheap swap-out, but the real question is 'What does it cost per year @$40 per swap-out, per vehicle?" This will be the foundation of ROI calculations (when an investment in an RO System can be deemed profitable).

Definitely, you could invest in a simple twin-filter housing and use 10" sediment and carbon before your DI Tank. This will extend the life of the resin for sure.

That said, the cost of RO ONLY water is practically free - and usually there is no gain in using RO-DI if you can use DI profitably. If you look at the design of Wash-iT PRO, I am firmly of the belief that every one should carry a DI ONLY system with them - they are foolproof.

The real question for you then, is “How much do you spend each year in $65 refills of your resin?”

If this answer was $500, I would suggest DI is extremely affordable for you …

If this answer is $1000, I would suggest that you can get a return from investing in a Wash-iT PRO (for example)

If this answer was $1500, then you will love working with an RO - guaranteed.


Brandon - I received this from our engineer this morning in regards to your issue -

[I]Hi Chris,

I read through the post and it sounds like the ¾ gpm regulator on the DI outlet may be malfunctioning. Please have him connect the supply water garden hose to the DI inlet (DI only mode) then take a flow test on the outlet. DO the flow test twice. Once with nothing connected to the outlet fitting and then a second test with the discharge hose without the pole connected to it.

As long as he testing, an additional test would be interesting as well.
· Supply water TDS
· RO only flow rate
· RO water TDS

These tests will help him and us understand his operating conditions.

I look forward to the results.

Have a great day![/I]

Any updates? This is happening to me too on higher inlet pressure systems while running ro/di.

Send me a PM with your info and I’ll send you some clamps for your 5/16" tubing. A little too much pressure and warm weather can easily cause the tubing to pop off the barbs.