Meiko Commercial Dishwasher Error Code 408: Change RO Pre-Filter
Message 408 on a Meiko M-iClean U with reverse osmosis tells staff to change the pre-filter of the reverse osmosis system. Replace the pre-filter with the water supply shut off. If 408 stays after the change, call us.
Low: a maintenance reminder; the machine keeps washing.
- Code
- 408
- Maker
- MEIKO
- Equipment
- Dish machines
- Applies to
- M-iClean U (red/gray messages)
What does MEIKO error code 408 mean?
A reverse osmosis system makes clean rinse water by pushing supply water through a very fine membrane. A pre-filter sits in front of it to catch sediment and chlorine that would damage that membrane. On the M-iClean U, the control shows message 408 when it is time to change that pre-filter. The manual lists it as an operator instruction. The machine is not shut down, but the filter is a wear item, and leaving it in place too long loads up the membrane and reduces the water the system makes. That in turn can lead to the holding tank messages in the 420s. The pre-filter is a consumable, much like the filter on a drinking water system, and its life depends on how much sediment the incoming water carries and how long since the last change. The maker's step is to replace the pre-filter. After a change, seal and seat the housing correctly and check for leaks when the water is turned back on.
Affected models and control systems
This applies to Meiko M-iClean U undercounter dishwashers with a reverse osmosis system. Machines without one will not show it, and other Meiko ranges use different numbers.
Code numbers and their meaning can change between control generations. We match the full model and control before acting on a code.
What you may notice
- Message 408 on the display
- Slower refill of the treated water tank
- A pre-filter that looks dark or clogged
Possible causes
Listed in MEIKO's documentation
- Pre-filter used up
- Sediment in the incoming water
- Time since the last change
- Filter housing sealing after a change
Other likely causes — what usually sits behind error code 408 on this control. A technician confirms which one it is before any part is replaced.
- Construction or main flushing nearby that sent extra sediment into the supply
- Filter housing O-ring pinched during the last change, so it seeps
Safe checks before calling for service
- Replace the reverse osmosis pre-filter, as the maker says.
- Shut the water supply valve to the system before you open the housing.
- Seat the new filter and check the housing for leaks when you open the water.
- Write the change date on the housing.
- If 408 stays after the change, note the filter type and call us.
How a technician diagnoses error code 408
- Confirm 408 and review the last change date.
- Check the housing seal and the connections for leaks.
- Measure inlet water pressure before and after the filter.
- Check the membrane output and the holding tank refill time.
- Inspect for sediment carryover.
- Replace the membrane only if output stays low with a fresh filter.
- Opening a filter housing on a pressurized line without isolating it can flood the cabinet next to live wiring.
- Judging the membrane needs pressure and output readings taken with gauges.
- A leaking housing seal is easy to misjudge and can run unnoticed behind the panels.
How error code 408 differs from similar codes
Message 410 and the 420s are supply and tank problems, while 408 is only the change reminder.
Technical reference
- Document
- M-iClean U Original operating instructions 9763258 (update 2026-06), 9.4.1 Messages p.43-45
- Edition
- 9763258 / Valid from: 2018-09 / Update: 2026-06
- Models / control
- M-iClean U (red/gray messages)
- Section
- 9.4.1 Messages, printed pp. 43-45 of 70 (PDF pp. 43-45)
- Checked
- October 2026
We use the maker's document to read the code and do not reproduce it. Always confirm the complete model and control before applying these steps.
Related MEIKO dish machine error codes
How often should the pre-filter be changed?
The manual does not give a fixed time. Change it when 408 appears.
Can I run without a pre-filter for a day?
It is better not to. Sediment and chlorine can harm the membrane.
408 is still on after the change. Why?
The reset may not have been done or the filter may not be seated. Call us if checking does not help.
Need help with MEIKO error code 408?
A technician confirms the cause on site and gives you the price in writing before any work starts.