Why is my dental suction weak?

Weak dental suction is usually caused by a blocked filter, either on the suction motor or in the chair. If it is weak on every chair, clean the suction motor filter. If it is weak on one chair, check that chair's suction filter, then the handpiece, then the hose. Clinic staff can clear most of these in a few minutes.

Is the suction weak on every chair, or just one?

This is the first thing to work out, because it tells you where to look.

• Every chair: the problem is at the suction motor. Go to the next section.
• One chair: the problem is on that chair. Skip to the three single-chair checks.

Weak on every chair: is the suction motor filter blocked?

If suction is down across the whole clinic, go straight to the suction motor. On Dürr and Cattani units the filter is yellow and easy to find. Take it out, clean it and test again.

If the filter is clean and suction is still weak everywhere, the motor itself may have a problem. That needs a technician.

Weak on one chair: check these three things in order

1. Is the chair's suction filter blocked?

Every chair has a filter in its suction line. If you are not sure where yours is, your operator's manual will show you. Take it out and check it. If it is blocked, clean it and test again.

2. Is the suction handpiece blocked?

A large piece of debris can lodge in the handpiece itself. It is more common on the narrower saliva ejector hose. Pull the handpiece off the hose and look through it. If there is a blockage you will usually see it straight away and can clear it.

3. Is the suction hose worn?

Suction hoses are made of two layers, an inner and an outer. Over time the inner layer can come away from the outer and start to close off the hose from the inside. The tell-tale sign is suction that starts fine and then gets weaker and weaker as you use it.

Quick test: Swap the hose with one from another chair. If the problem moves with the hose, you have found it. If you do not have a spare, shine a torch into the hose and look for anything blocking it.

Fix: Replace the hose.

How do I stop this happening again?

Flush the suction lines with an approved suction cleaner at the end of every day, and clean the chair and motor filters on a set schedule rather than waiting for suction to drop. Most weak-suction callouts trace back to lines and filters that have not been cleaned regularly.

Still weak?

If you have checked the filters, the handpiece and the hose and suction is still poor, the fault is inside the chair. Common causes are worn diaphragms in the selector valves, blocked internal hoses or a faulty valve, and these need a technician.

Call Universal Dental Solutions on (02) 8313 0559. Tell us whether it is one chair or all of them and what you have already checked, and we will come prepared.

Frequently asked questions

Why does my suction start strong and then fade?

This is the classic sign of a suction hose whose inner lining has separated. Swap the hose with another chair to confirm.

How often should dental suction filters be cleaned?

Chair suction filters should be checked daily and cleaned as needed. The suction motor filter should be checked at least weekly. Follow your equipment manufacturer's schedule if it specifies one.

Can a full amalgam separator cause weak suction?

Yes. On systems with an amalgam separator, a full or faulty separator can reduce suction across the clinic. Most separators have an indicator or alarm; check it if the motor filter is clean and suction is still weak everywhere.

What is the yellow filter on my suction motor?

On Dürr and Cattani suction units the yellow filter is the main inlet filter that stops debris reaching the motor. It is designed to be removed and cleaned by clinic staff.