The same you d buy at any grocery store.
Cleaning filter on tankless water heater.
Know that a tankless water is not a set it and forget it water heater.
Add an adapter to the inlet side.
5 steps to cleaning your rinnai tankless water heater filter learn best practices on cleaning your filter from our youtube video learn more.
With the water running out of the hoses turn the valve off on both hoses to stop the flow of water and preventing air from getting into the water heater.
Turn the cold water off and remove the filter screen again and clean it under running water.
Close the cold and hot water ball valves on the unit.
Remove the hose from the cold water side and screw the cap back in place.
Reinstall the filter screen.
Then place a bucket under the cold side fitting to minimize any spills.
The rinnai is typical.
E407 e421 and e432 issues.
How to flush a tankless water heater and clean the air intake filter step 1.
Unscrew the water filters and rinse them before putting them back into place.
Wrap the outlet fitting s threads with teflon tape and tighten it to the outlet side of the filter.
Turn the water supply on slowly again to about 1 4 way open.
Locate the shutoff valves.
These are short circuited problems which are the real serious ones that you should call for tech support.
You should visit the heater at least once every three months.
Cut through the cold water pipes using a hacksaw and clean the edges with emery cloth.
Using the adjustable wrench unscrew the braided stainless steel hose from the cold side connection and remove the filter screen using the needle nose pliers.
I decided to purchase mine through amazon.
Open the water valve and let 4 to 5 gallons of water flow through the system.
The solution is the same as for issue e012 that you should clean the air intake filter.
Add teflon to a threaded fitting and tighten this into the adapter with a pipe wrench and pliers.