Looking to add spot free rinse

[Jason Studer]

I have a four bay self serve that has never had spot free rinse, not many if any near me have spot free.

Just a few questions

1 What pressure do you suggest running it at? I have had one company say low pressure like presoak, and another says high pressure like your normal rinse.

2 What % of customers use it and for how long?

3 What is the cost to maintain and operate? Trying to do the math to see if its worth the investment.

Thanks for your input. Jason

 

[loewem]

1. Mine is set to run at lower pressure around 150 PSI. Have never seen it run at high pressure.

2. 75% or more use it.

3. Not much maintenance needed. Change the prefilter a couple/few times each year, change the membranes every couple of years, change the carbon filter media every five years. I think some maintenance depends upon the quality of yoir water. The membranes are expensive.

 

[MEP001]

I would run it at "low pressure" about 200-250, or medium pressure, about 450-500. The latter takes a big pump and is much more expensive. You can get 250 with a 2500 series Procon and 3/4 HP motor and still use Kip solenoids with a 3/32" orifice.

I like the 450 psi range, and I believe the customers do too. I can't quote an exact number but somewhere between 2/3 and 3/4 of them use it. I've watched people go around for 4-5 minutes at a time. Smart people who use it after rinse to push off the dirty water still use it a couple minutes.

I would not deliver it to the bays at high pressure. You don't want your customers using it instead of regular rinse, you want them to use high pressure rinse and then spot free. It would be very inefficient for you otherwise.

Cost to maintain can be very low depending on a lot of circumstances. If everything else is kept up, membranes should last at least five years. I prefer to change the carbon filter media with the membranes, or at five years, assuming it's sized properly to the system. I have seen them undersized and need to be refilled every year.

Cost of operation depends on the efficiency of the unit as well as whether you capture and reuse the reject water. Best efficiency units will reject one part for every part of product. In my experience, an RO system set up for 1:1 and recirculating part of the reject will have a higher production rate and longer membrane life.

It's worth the investment. Every self serve car wash should have it.

 

[soonermajic]

can you increase your gpd, by simply adding an extra housing & membrane?

 

[MEP001]

Yes and no, if the system was sized correctly you won't get much of an increase by adding a membrane because then the pump will be undersized. Then if you put in a bigger pump and motor the electrical will be undersized, then the flow meters and plumbing won't be big enough. Either replace it or re-engineer it.

 

[getnbusy]

I'm sure you already have, but the first thing I would do is check my water to see what I'm working with. My area has pretty darn good water so a spot free setup is not necessary. I put it in anyway a few years ago and have found that my customers really don't use it. I guess because we don't need it. So don't put it in just to add a feature or take up a spot on the switch. There may be a reason nobody has it.

 

[MEP001]

I'm sure you already have, but the first thing I would do is check my water to see what I'm working with. My area has pretty darn good water so a spot free setup is not necessary. I put it in anyway a few years ago and have found that my customers really don't use it. I guess because we don't need it. So don't put it in just to add a feature or take up a spot on the switch. There may be a reason nobody has it.

That's a good point. IMO the best test is to wash a dark car (Use wax to get lots of water beads) and let it dry in the sun.

I've been in several towns where the water is so bad that you have to scrub spots off the windows with 0000 steel wool.

 

[Greg Pack]

I would go with lower pressure, but use bigger solenoids. I had a a Pur-clean system that was plumbed with a 1/4" solenoid manifold. I started having intermittent problems with one bay, so converted to individual 3/8" solenoids. The flow difference was very noticeable, enough where I won't ever use a medium pressure setup again.

 

[mjwalsh]

I would go with lower pressure, but use bigger solenoids. I had a a Pur-clean system that was plumbed with a 1/4" solenoid manifold. I started having intermittent problems with one bay, so converted to individual 3/8" solenoids. The flow difference was very noticeable, enough where I won't ever use a medium pressure setup again.

Greg,

I wonder what the ratings are on your Pur-clean pump-motor setup? It seems like you must have some extra capability going on ... otherwise the end nozzle would tend to be the most restricting ... more so than the smaller than 3/8" solenoids you were running before.

I do agree that if more spot free water can be forced through the nozzle ... the customers would probably be happier than with more than 200 psi by itself.

 

[MEP001]

I would go with lower pressure, but use bigger solenoids. I had a a Pur-clean system that was plumbed with a 1/4" solenoid manifold. I started having intermittent problems with one bay, so converted to individual 3/8" solenoids. The flow difference was very noticeable, enough where I won't ever use a medium pressure setup again.

Did you ever check the MOPD of the solenoids? I've worked on a few where they had the pressure set to 200 PSI but the solenoids could only open at 150 or below. It worked as long as no one selected on spot free in a second bay.

I've also seen a few washes where they only ran about 150 psi to the bays but used large solenoids, and the pressure at the bay was very good. I would have thought a small solenoid with a 3/32" orifice wouldn't affect flow since the tip is even smaller, but apparently it does.

 

[Greg Pack]

Im prewtty sure I used a Dema 453 which looking at the specs has .350 orifice.

Edit- I used GC solenoids.

In a previous life I was a fire fighter. We studied hydraulics in apparatus operator courses. The take home from those courses is every time you did something to a stream of water- squeeze it into something smaller, split it, even just change it's direction with an el, there was a resultant change in pressure that had to be accounted for with an adjustment in pump pressure. As a rule of thumb Bigger is better from one end to the other. I figured the larger solenoid had to help, but I was pleasantly surprised it helped as well as it did. The flow went from being marginal to quite adequate for SFR usage.

 

[mjwalsh]

Im prewtty sure I used a Dema 453 which looking at the specs has .350 orifice.

In a previous life I was a fire fighter. We studied hydraulics in apparatus operator courses. The take home from those courses is every time you did something to a stream of water- squeeze it into something smaller, split it, even just change it's direction with an el, there was a resultant change in pressure that had to be accounted for with an adjustment in pump pressure. As a rule of thumb Bigger is better from one end to the other. I figured the larger solenoid had to help, but I was pleasantly surprised it helped as well as it did. The flow went from being marginal to quite adequate for SFR usage.

Greg,

Good information ... sometimes it can be a reminder of what we may already kinda know of. Sort of bringing it to the forefront so to speak.

This is the reasoning of why during a project ... a friend-mechanical engineer told me his was short on time to be able help me ... but if I narrowed down every fitting & length for my "in house facility" project & gave it to him on a sketch & a list ... he would be in a position to help because of the legwork I would have already done. It involved bring piping over to the car wash ER from our laundromat ER to integrate some of the boiler btus etc. The project went well despite of the mechanical contractor falling asleep during a key meeting with the engineer & myself!