SpectraPure Maxcap Questions

[CastAway]

Setting up my system. First time. I have a few questions:

The two DI canisters don't seem to fill, but both product and waste water flow. Should these canisters fill all the way? The water just trickles in.

The pressure gage on the RO unit is just measuring pressure across the membrane itself, right? This is not my tap pressure is it?

Without cutting the flow restrictor at all, I am at a 4:1 ration already, but only putting out about 38 gpd instead of 90. Does this mean I need a booster pump?

One of the SpectraPure videos said the nominal operating temp is 77 degrees F. What are the implications if my tap water is much much colder than that? Should I be measuring temperature and compensating somehow?

Thanks in advance for any help?

 

[RacinRevo0818]

Setting up my system. First time. I have a few questions:

The two DI canisters don't seem to fill, but both product and waste water flow. Should these canisters fill all the way? The water just trickles in.

I loosen the canister till air is out

The pressure gage on the RO unit is just measuring pressure across the membrane itself, right? This is not my tap pressure is it?

Sounds correct

Without cutting the flow restrictor at all, I am at a 4:1 ration already, but only putting out about 38 gpd instead of 90. Does this mean I need a booster pump?

I'm sure some one else will chime in but I'm guessing thats if you have all your filters in peak ( yours are new) temp of water entering unit and pressure of incoming water all play large factor in waste water. Booster pumps seem to help with waste if water pressure is under 50 psi.

One of the SpectraPure videos said the nominal operating temp is 77 degrees F. What are the implications if my tap water is much much colder than that? Should I be measuring temperature and compensating somehow?
I've heard a lot of discussion about this and most say don't use water from hot water for some reason. I'm sure AZdesertrat will chime in as he seems to have this rodi stuff down.

My production usually goes up when warmer weather gets here!!

Thanks in advance for any help?

 

[CastAway]

I loosen the canister till air is out.

Worked like a charm. Thanks!

 

[CastAway]

Definitely going to need that booster pump. This initial fill is gong to take a few days. Need too many other things first though. :squigglemouth:

 

[AZDesertRat]

Doesn't matter, it is normal to have headspace in the DI canisters since they are gravity and not under pressure. Even if you unscrew it and fill them, first time the outlet line drops below the canister the leve drops again. It is perfectly normal and does not affect resin life or performance. The water actually travels down the outside of the cartridge then up through the center where you don't see it.
I have used all forms of the MaxCap, 90 GPD, 180 GPD dual membrane and now the 100 GPD+ UHE 1:1 for the last 10+ years and they do not come any better at any price.


Two things have a major effect on RO or RO/DI performance, water pressure and water temperature. The gauge will be vry close totap water pressure when the filters are new and not causing headloss. 40 psi is the absolute bare minimum and 60-80 or higher is preferred. The higher the pressre the more efficient the RO membrane will be, I run mine at 95-100 psi and get 99.4% rejection rate, at 40 psi it would be much lower so DI would not lastearly as long.

Water temperature is the other big factor but DO NOT mess with what you have. Cold water actually treats better since it is less viscous or more dense and the contaminants donot pass as easily through the membrane so get flushed away and only the pure water goes through. To counteract the effect of coldwater on the GPD, boost the pressure, not warm the water.

What is your pressure? Is your water feed turned all the way on? Do you possibly have a pressure regulator on your home wate rsupply or are you on a domestic well system?

 

[CastAway]

Thanks! I had read about cold water and membranes. I'll consider that a benefit. I tossed the 1/4" feed line that came with the unit, and put in a 3/8" feed, in naïve hope that the larger line would result in more pressure/flow. I think the saddle on the copper line is still a restriction point, and a soldered fitting would have been best, but oh well. Based on the pressure across the brand new membrane, I think my household tap is at 43psi. Sounds like I just need the booster pump, to save time, and get a little better rejection rate. Right now I'm getting 98.5% on average, although it seems to vary with total time running, and, starts and stops. Once the initial fill is complete, I'll put in a booster pump, flush, and perhaps another pressure gage, etc.. Thanks DesertRat

 

[AZDesertRat]

The 3/8" line will not make any difference unless you have an extremely long run to the RO/DI from the source and have line losses due to friction. Saddle valves plain old suck, I have had more problems with them over the years than I care to count. If you have a sink or toilet close by use a feed water adapter valve which does not permanently alter plumbing and will give you a reliable source.

One way to check if your sadlle valve is the culprit or not is to turn the RO/DI on then install a closed ball valve, pinch or kink both the treated and waste lines at the same time and see what the pressure rises to under static non flowing conditions. If it rises more than a few psi above what you have been seeing then it is causing a restriction.

If you decide to install a booster pump, only consider the Aquatec 8800. There are cheaper clones out there but they do not last as well nor have the history and track record the Aquatecs do. Also the 6600 and similar pumps are not large enough and will burn up trying to keep up.

Rejection rate will change with temperature, pressure and incoming TDS. It also changes early in the run due to TDS creep and osmotic pressure changes.