You turn on the shower and expect to be greeted by a hot, steamy flow of water just waiting to start your morning off the right way.

To your surprise, it’s a cruel, cold stream that seems to taunt you, almost guaranteeing that your day is going to suck.

Once you come to your senses, you remember you have a tankless hot water heater in your home. Which basically means that you should always have hot water, right?

Yes, tankless hot water heaters are more efficient and have a longer life than standard hot water heaters. They also should almost eliminate that 6 AM surprise of icy cold water – if you have the correct size AND it’s taken care of.

When your tankless hot water heater is running cold, it’s time to investigate. Here are the most common reasons your tankless hot water heater is not heating water:

First Things First: Size Matters

You have a tankless hot water heater because you don’t ever want to be without hot water. That’s a great plan, but if your household puts too much demand on the water heater, you’ll turn up cold. The first sign that your unit is too small for your home is constantly running out of hot water or overloading the system.

Your tankless system can shut down under pressure if it’s too small for the job you’re asking of it. In other words, if you try to use too much hot water at once or too much in a short period of time, it will shut down and your water will be cold. You’ll need to reset the unit in some cases.

If you notice you’re running out of hot water or resetting the unit a lot, you can upgrade to a larger tankless hot water heater to meet the demands of your family or install a second unit to keep up if reducing your hot water consumption isn’t possible.

Maybe the Fire is Out

If your tankless unit isn’t heating water, check the unit.

Do you see a “no ignition” message?

This means that the unit is trying to light to heat the water but can’t for some reason. You may have an empty propane tank or a forgotten gas bill. If you suspect this is the case, call your provider. In other cases, you may have an issue with your ventilation or gas line that requires expert attention.

Do you see a “flame failure” message?

This message usually indicates there’s an electrical or gas issue. First, check the propane and gas bill like we mentioned before. If this isn’t the problem, you’re dealing with a problem with the gas pressure that can be caused by combustion problems, venting, regulator failure, and more. You’ll need to call an expert, and have it inspected.

Mineral Buildup or Corrosion Damage

Corrosion isn’t a common problem that tankless hot water heaters have, thankfully. But it can happen if condensation drips onto the gas burner. The corrosion can block the gas supply going to the hot water heater and cause the system to shut down. A plumber can identify this problem for you.

Mineral buildup happens if you have water that’s full of minerals, also known as hard water. Mineral buildup can damage the water heater or even cause it to break completely, requiring a brand new heater. If you have hard water and your tankless unit stops heating the water, you may want to call a plumber to come inspect the unit for potential mineral buildup.

If you find your tankless hot water heater not heating water, give us a call today and our experts will get you back to your hot shower in no time.