- A knocking noise will happen on the machine’s first use, each time it runs out of water, and if it sits for an extended length of time allowing the water to evaporate
- Fill tank with water
- Plug machine in
- Wait until the noise goes away (approximately 1 1/2 minutes)
- This is the normal sound of the pump tying to pull water through the machine
- Noise will change from a knocking sound to a muffled hum after water enters the pump
- If noise continues past 1 1/2 minutes, continue troubleshooting:
- Confirm the water tank is seated properly with no gaps
- It will “click” into place once it is seated properly
- Ensure the cap and insert assembly is screwed on straight to the water bottle
- If not, tank will not sit correctly in the machine and will not release steam
- Plug machine in
- It should only knock for up to 1 1/2 minutes until it starts steaming, then knocking will diminish to a dull or muffled hum
- If the machine continues to knock loudly after following these steps, take machine to a BISSELL Authorized Service Center or Contact Us
- Confirm the water tank is seated properly with no gaps
