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Dental suction servicing: wet vs dry systems, intervals and what a service covers
Suction gets noticed only when it stops working properly, which is usually well after the maintenance that would have prevented it stopped happening. What your system needs depends heavily on which type you have — and a surprising number of practices are not certain which that is.
Which system do you actually have?
There are three arrangements in common use in UK practices, and they have materially different maintenance needs. The simplest test is whether water flows through the pump while the system is running.
| Wet | Dry | Semi-wet | |
|---|---|---|---|
| How it works | Water ring pump; continuous water flow generates suction and carries waste | Motor-driven air pump; waste separated from air | Air pump with a small amount of water introduced |
| Water supply | Required, continuous | None | Minimal |
| Running cost | Higher — water usage | Lower | Between the two |
| Upfront cost | Generally lower | Generally higher | Varies |
| Noise | Tends to be quieter | Tends to be louder | Varies |
| Main maintenance issue | Limescale and water-related blockages | Filters and separation stage | Reduced blockage risk vs dry |
If you are unsure, look at the pump while a surgery is using suction. Visible continuous water flow means wet. No water supply at all means dry. A small, intermittent water feed suggests semi-wet.
Why it matters beyond curiosity. Wet systems generally need more maintenance because the continuous water flow brings limescale and mineral build-up with it. If you have inherited a practice and are working to a maintenance schedule written for a different system type, you may be doing the wrong tasks at the wrong frequency.
How often does suction need servicing?
Manufacturers generally recommend an annual service by a suitably qualified dental engineer. That sits on top of routine tasks the practice handles itself.
| Task | Frequency | Who |
|---|---|---|
| Flush lines with an approved cleaning solution | Daily | Practice |
| Check and clean filters and traps | Weekly (or per manufacturer) | Practice |
| Check amalgam separator level | Per manufacturer | Practice |
| Full system service | Annually | Engineer |
| Amalgam separator service | Annually, with written proof | Engineer |
| Replace worn hoses and seals | As identified | Engineer |
Daily flushing is the task that carries the most weight and is the easiest to let slide. Lines that are not flushed accumulate deposits, suction performance falls gradually enough that nobody notices, and the eventual blockage arrives as an unplanned callout.
The compliance side
Suction servicing is largely a manufacturer recommendation. The amalgam separator attached to it is not.
Any practice using amalgam must have a separator meeting the required standard, it needs annual servicing at minimum, and you need written proof of the work to demonstrate compliance. That documentation is expected by CQC, the GDC and the environmental regulator.
This is covered properly in our guide to amalgam separator regulations — worth reading if you are not certain where your paperwork stands.
Not sure what type of system you have or when it was last serviced? Tell us what is in your plant room and we will work it out with you. Ask us.
What a proper suction service covers
| Item | What should happen |
|---|---|
| Filters and traps | Inspected, cleaned or replaced as required |
| Amalgam separator | Serviced to schedule; certificate issued |
| Lines and hoses | Checked for wear, leaks and deposits |
| Seals and connections | Checked for air leaks that reduce suction |
| Pump performance | Suction measured against specification, not just "sounds fine" |
| Descaling (wet systems) | Carried out as required for limescale build-up |
| Separation stage (dry systems) | Inspected and cleaned |
| Documentation | Written report of work carried out — needed as compliance evidence |
The measured performance check is the one worth insisting on. Suction degrades gradually, so a system can be noticeably below specification while still feeling acceptable to whoever is using it every day.
Common causes of lost suction
Before assuming the pump has failed, these are the usual culprits, roughly in order of likelihood:
- Blocked or full filters and traps — the first thing to check, and often the whole answer.
- Full amalgam separator — needs emptying before it reaches capacity, not once it has.
- Line blockages — deposits building up where daily flushing has been inconsistent.
- Air leaks — a perished hose or a poor seal will quietly reduce suction across every surgery on the system.
- Limescale (wet systems) — the continuous water flow means scale is an ongoing consideration, not a one-off.
Where suction has dropped across all surgeries at once, look at the pump end and the shared lines. Where it has dropped in one surgery only, the problem is far more likely to be local to that chair.
Frequently asked
How often should dental suction be serviced?
Annually by a qualified engineer, with daily line flushing and regular filter and trap checks handled by the practice.
What is the difference between wet and dry suction?
Wet uses a water ring pump with continuous water flow. Dry uses an air pump and no water supply. Semi-wet introduces a small amount of water to reduce blockages.
How do I know which I have?
Watch the pump while suction is in use. Continuous water flow means wet; no water supply means dry.
Why has suction dropped?
Usually filters, traps, a full separator, a line blockage or an air leak — check those before assuming the pump has failed.
Suction not performing as it should?
We service, repair and install dental suction systems for practices across the UK, including amalgam separator servicing and the documentation you need to evidence it.
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