If the CPAP machine is producing low oxygen concentration or low pressure, or the machine sounds strained or is getting hot, there may be an internal air leak.

To check for leakages in the CPAP’s internal tubes, you will need the machine to be opened and powered on. You should therefore carry out these checks with extreme caution to avoid the risk of an electric shock.

Make sure the CPAP is running and the flow meters are both open at a normal operating level.

First, check around the bottom of each sieve bed. This is a common place where air leaks can happen.

You can hold a piece of tissue paper around the joint to check whether air is escaping. If air is leaking, you may simply need to tighten the tube clamp that connects the hose at the bottom.

Rotate the screw clockwise and check whether this has stopped the leak. If not, there may be a crack in the hose itself.

Next, check throughout the inside of the CPAP machine for any tubes that may have come loose. Reconnect these and check that they are firmly attached.

You can also check that each tube is securely connected throughout the machine. Lightly pull on each tube to make sure that it stays connected.

Also, look out for any kinks that may be affecting airflow.

If the end of a tube is not fitting tightly, you might be able to secure it with a zip tie or crimp. You could also cut off this tip and place the same tube back in place for a tighter fit.

If you suspect that there is a leak partway along a tube, you can check this by submerging it underwater. You may be able to do this carefully while it is still attached. If it is not easy to access, you will need to remove the tube to test it.

If you see air bubbles coming from the length of tubing, it is no longer airtight, and this piece of hose should be replaced. Ensure that everything is fully dry after testing. There may be also air leaking from the connection between the pressure valve and the reservoir tank. To tighten this, first switch off the machine.

Disconnect the hoses from the pressure valve.

You can then rotate the valve for one full turn so it is positioned the same way.

This should be enough to make a secure seal. Be careful not to force it.

Then reattach the tubes.

You can now switch the machine back on and test that the connections are secure and not leaking air.

Another area where air leakage can happen is where the top valve connects to the reservoir tank.

With the machine switched off, release the clips that hold the tube in place and slide out the tube.

If the valve’s connection is loose, tighten this by hand. Rotate clockwise until it feels secure, but don’t over-tighten it. Then slide the tube back into place and reattach the clip.

Then reassemble the CPAP machine, turn it on and test whether the issue is resolved.