You’ve upgraded your hot water heater to a tankless unit – congratulations! There are some great benefits to a tankless water heater.

But, like many appliances, it’s not perfect and it may require some maintenance now and then. Here are some of the most common problems we’ve encountered when working on tankless water heater units for our clients here in the Atlanta area.

  • Tankless water heater keeps shutting off
  • Water heater is suddenly cold
  • Tankless water heater won’t ignite

Electric Tankless Water Heater Keeps Shutting Off

There are a few things that could be causing your electric tankless water heater to shut off.

  • It could be something as simple as a loose wire. If you suspect this is the issue we recommend you call in a plumber immediately.
  • Check that the heater is getting electricity, gas and water.
  • Check the filter to make sure that there’s no debris in it.
  • Finally, the problem may have to do with low water flow rate. Some tankless water heaters have a minimum flow rate requirement and if that number is not reached, then the heater will not turn on. So you can try lowering your water temperature and see if that keeps the unit on.

Tankless Water Heater Suddenly Cold

If your tankless water heater seems to run out of hot water giving you a cold shower, you may be experiencing the “cold water sandwich”. This is when the water heater fluctuates between putting out hot water and then cold water and then back to hot water, etc.

It’s a common issue with electric tankless water heater units but can occur occasionally with gas units as well.

What could cause this problem? A variety of issues such as…

  • A problem with the flow sensor
  • The filter could be dirty, have some excess debris
  • Corrosion on the lines
  • A problem with the heat exchanger
  • Venting pipes that weren’t installed properly
  • The wrong size gas lines were used during installation

This is a problem that should be attended to by a professional plumber.

Gas Tankless Water Heater Ignition Failure

Two things could be happening here.

1. The error message is “No Ignition”

This means that the mechanism is trying to light but it’s unable to. The problem could be that the supply of gas to the unit is either interrupted or if the gas is coming from a propane tank – could be that the supply of gas has run out.

The problem could also be a venting issue.

2. The error message is “Flame Failure”

This error message tends to indicate a problem with the gas pressure. Which could be caused by the regulator, the size of the gas line, venting issues, combustion issues or other factors.

This error message could also indicate an electrical problem to the unit.

Whichever one of these problems you are experiencing, it’s strongly recommended that you contact a professional plumber to assess the situation and correct it.

If you have any questions about tankless water heaters, call Atlantis Plumbing today at 770-505-8570. We are available 24 hours a day, 7 days a week.