Used Kent Maxxima RO/DI

[schulzcm]

I have recently purchased a used Kent Maxxima RO/DI. I am not sure if it is the 35 or 60 GPD. Is their anyway to tell? Another thing is that the "good" water is coming out extremly SLOW. What should I replace if anything. I believe the filter has not been used in a few months. TIA.

[AZDesertRat]

Water will be extremely slow at best, you are only talking 1.4 to 2.5 gallons of water per hour ie. 35 or 60 gallons per day. And that is only if you have 60 psi pressure and 77 degrees F water temperature. Normally people get about 60 to 75% of the rated flow per day out of units.
You should at a minimum replace the prefilter, carbon block and DI resin as you don't know the condition of them. The only way to tell if the membrane is good is with a TDS meter, I hope you got one of those with the unit? You need to sample the TDS from the Tap, RO only and combined RO/DI to determine the efficiency. You should be seeing in the neighborhood of 96 to 98% TDS removal with the RO only and 0 TDS after the DI portion.
Buying a used RO/DI system can be a gamble unless you know who you are buying from and how it been used and maintained. Sometimes replacement costs exceed the cost of a new unit.
Luckily that unit uses all standard sized replacements so any of the RO vendors here on RC can supply you with replacement filters and DI resin or a replacement cartridge, I would go with a refillable DI cartridge if it does not already have one.

[Thefilterguys]

AZ is right you need to change your sediment carbon and DI to start with since the thing has been sitting. You also should have a TDS meter to assess your membrane. Even if the membrane is OK you'll need a TDS meter to know your getting good quality water.

Jim