Removing Scaling From An Electric Tankless Water Heater

If you use a tankless water heater within your home, routine maintenance steps should be taken to keep the interior of the unit free of lime scale. This, along with other minerals within water, can cause the water heater to run less efficiently as it will need a longer burn cycle to output warm water. To keep your tankless water heat running with the maximum efficiency level, regular cleaning of the unit can keep scale from building up. Here are some instructions on how to remove lime scaling from a tankless water heater.

Take Safety Precautions

Before working on your tankless water heater, you will want to turn off the electricity so the water heater does not come on while you are cleaning it out. Turn off the electricity at the main circuit panel in your home. You will also need to turn off the water supply at the main valve supplying water to your home. After this is done, turn off the cold and hot water valves attached to your water heater. This will keep cold water from going into the heater and will keep hot water from coming out when you are cleaning it.

Remove The Purge Port Valve Caps

After the hot and cold valves have been shut off, you will need to remove the purge port valve caps. These are located on the purge valves, which are attached to the main valves you had just turned off. To remove the caps, gently unscrew each valve cap using the "T"-shaped handle. Do this slowly as there will be pressure within the pipes.

Know How The Purge Ports Work

The blue cold water valve has a purge port that is used as a flushing inlet. The red hot water valve has a purge port that is used as the flushing outlet. This means the red valve will need to be opened to remove water from the heater. The cold valve will need to be opened so cleaning solution can be added to the heater. To open a port, it needs to be turned so it is parallel with the purge port valve body. To close a port, it needs to be turned to a perpendicular position to the purge port valve body.

Remove Water From The Lines

Consult your tankless water heater manual to see if you will need a sump pump to remove water from the heater or if you can hook up hosing line to the hot water purge port. Open the red hot water purge valve so any water in the pipes will be redirected through hosing line or sump pump line to a bucket.

Clean The Water Heater

Use distilled vinegar to clean out your water heater. Never use chemicals to clean out the water heater, as this is a potable water supply. Turn off the hot water purge valve and turn on the cold water purge valve. Pour a few gallons of vinegar into a bucket and place the tube connected to a circulating pump into the bucket. The other end will be connected to the cold water purge valve. When you turn on the circulating pump, the tube will redirect the vinegar into the water heater. Consult your manual to see how long you should allow the vinegar to rinse the heater. After the flushing is complete, turn off the cold water purge valve and turn on the hot water purge valve to remove the vinegar from the unit. 

Start The Heater Back Up

When it is time to turn the heater back on, make sure both purge valves are in the off position. Remove the tubing, replace the caps, turn the power back on and restart the water heater. You can then slowly turn the purge valves back to an on position. Turn the cold and hot water valves back on. Lastly, turn on the main water supply. If you have more questions about your water heater, contact a company like First Class Plumbing of Florida Inc.