A centrifugal separator is close to maintenance free by design: no cartridge, no media, nothing consumed. That is precisely why it is neglected, and it has exactly one requirement. The collection chamber fills, and when it does the separator stops separating and passes grit straight through while looking entirely normal from outside.
The purge is the whole routine
Separated grit accumulates in a chamber below the body and has to be removed by opening a valve under line pressure, which blows it out. Doing that briefly and often is far more effective than doing it thoroughly and rarely, because a chamber allowed to fill has already stopped the separator working. An automatic purge valve on a timer suits a household that will not remember, and is worth fitting where the sand load is steady rather than occasional.
Where the purge water goes
Somewhere that can take grit. Not into a septic system, where it accumulates, and not onto planting or a path where a stream of sand will build up. A floor drain, a sump, or a discharge to a suitable outside point are the usual answers, and the line should be short and unrestricted, since the purge relies on line pressure to carry material out. A partly closed supply valve makes a purge far less effective without any sign that it did.
The flow range, which is a design matter
Separation depends on water entering fast enough to spin, so a separator has a working flow range rather than a maximum. Below it, velocity is too low to throw particles outward and performance falls off, which means an oversized unit on a modest well performs worse than a correctly sized one. If separation seems poor and the chamber is not full, check the flow against the specification before suspecting the unit.
What it will never do
Remove fine silt that stays suspended, organic material, or anything dissolved. It is a first stage, and a cartridge or media filter behind it deals with what it cannot. If the chamber fills within days on a well, that is information about the well rather than the separator: a failed downhole screen, a pump set too low, or a deteriorating formation, none of which are fixed at the house. Our sand filter media guide covers the stage that follows it.
Questions people ask about centrifugal sand separator
What maintenance does a separator need?
Purging the collection chamber, briefly and regularly. Nothing wears out, but a full chamber stops it separating.
Where should the purge discharge go?
Somewhere that can take grit: a floor drain or sump, not a septic system and not onto planting or paths.
Why is separation poor when the chamber is empty?
Flow outside the unit's working range. Too little velocity and particles are not thrown outward, so an oversized unit underperforms.
The chamber fills within days. What does that mean?
On a well, that points at the well: a failed downhole screen, a pump set too low or a deteriorating formation.