Tankless water heaters are great, but mineral buildup can kill their efficiency fast. Heres how to clean a tankless water heater.
When my wife and I installed a propane-fueled tankless water heater in our home eight years ago, we were excited about the small footprint, convenience and efficiency it promised. It delivered on our hopes, but theres one thing we didnt count on: A gradually and significant drop in efficiency thanks to our mineral-rich water.
As our well water flowed through the heater, the minerals coated the heat exchanger inside. Soon, we discovered we were burning more propane. Eventually we learned our lesson and started cleaning our water heater regularly. Its performed great ever since.
All water heaters need cleaning from time to time, especially if you live somewhere with hard water. Tank-style heaters are usually easy to clean. Its somewhat trickier for tankless units, but you can do it with the right tools and approach. Keep reading for my preferred method for cleaning a tankless water heater.
Set up pump and hoses
- Set up a chair next to your water heater with a towel on top of the seat.
- Place your portable transfer pump on the towel. (The towel prevents the pump’s vibration from damaging the finish on your chair.)
- Thread the short hose onto the pump’s inlet port. Many pumps indicate which direction liquid flows with an arrow. If yours does, thread the short hose onto the port opposite to the direction of the arrow.
- Thread the long hose with interior threads on each end on the other port. Thread the other end onto the service valve leading to the cold water inlet valve.
- Thread the second long hose (with threads only on one end) onto the service valve leading to the hot water inlet valve.
Robert Maxwell for Family Handyman
Project step-by-step ( Step 1
- Switch off your tankless water heater, then unplug it.
- Shut the water inlet and outlet valves.
- Place a large bowl or basin below the service valves leading to the heater. Open the valves and remove their end caps with channel lock pliers.
- Allow any water in the heater to drain into the bowl.
Robert Maxwell for Family Handyman Step 2
Tankless Water-Heater Maintenance
FAQ
Can I use vinegar to flush my tankless water heater?
Can I flush my tankless water heater myself?
How do you clean a hot water heater?
Step Instructions Step 1 Shut off gas or electricity and water supply. Step 2 Connect sump pump and hoses. Step 3 Submerge pump in vinegar-filled bucket. Step 4 Run pump for one hour to descale the heater. Step 5 Flush system with fresh water to remove residue.
How do you clean a tankless water heater?
Tank-style heaters are usually easy to clean. It’s somewhat trickier for tankless units, but you can do it with the right tools and approach. Keep reading for my preferred method for cleaning a tankless water heater. Multiple batteries and charger for pump (if using a cordless model) Switch off your tankless water heater, then unplug it.
How do you flush a water heater hose?
You now want to flush out any remaining cleaning agent or vinegar. To do this, keep the hose connected to the hot water outlet valve and turn on the cold water inlet valve. This will push water up the system and flush out everything through the hose on the hot water side.
How do you clean a water heater with a submersible pump?
Disconnect the electricity and close the gas isolation valve. Connect hoses from a flush kit to the cold and hot water service ports, and place the submersible pump in a bucket filled with a descaler solution or white vinegar. Let the solution circulate through the water heater for at least an hour.