Why does my tankless water heater go cold during shower?

So to avoid damage to the heat exchanger (and to avoid scalding you with super hot water), your tankless unit will shut itself off, leaving you with cold water in the middle of your shower.
Takedown request   |   View complete answer on georgebrazilplumbingelectrical.com


Why does hot water go cold in the shower?

Your shower has faulty pressure-balancing valves.

Faulty valves are common causes of temperature fluctuations in the shower. The pressure-balancing valves, also known as thermostatic mixing valves (TMV), blend cold water with hot water to provide constant and safe shower temperatures, preventing scalding.
Takedown request   |   View complete answer on marcoplumbing.ca


Why does my tankless water heater not stay hot?

The Air Supply or Exhaust Is Blocked

At times, your exhaust or air supply might get blocked, which can cause your tankless water heater to stop heating. Many water heaters will automatically shut off as a way to protect the appliance and help prevent other safety hazards that could result.
Takedown request   |   View complete answer on abchomeandcommercial.com


Why does my tankless water heater fluctuate in temperature?

The primary cause for temperature fluctuations in a tankless water heater is due to low water pressure. If the water flow in your tankless water heater is too low and dips below the flow activation rate, the main gas burner will turn itself off.
Takedown request   |   View complete answer on bestplumbersclub.com


Why is my shower water suddenly cold?

If your showerhead mixer valve is broken, you may regularly experience a cold shower. The mixer valve is responsible for mixing hot and cold water to ensure it delivers the temperature you've selected.
Takedown request   |   View complete answer on duncanhtg-ac.com


Why does my tankless hot water heater go cold?



How do you fix fluctuating water temperature?

Shower Water Temperature Keeps Changing
  1. Check Your Pressure-Balancing Valve.
  2. Check Your Water Heater.
  3. Replace the Shower Cartridge.
  4. Descale the Water Heater and Check for Blockages.
  5. Why Your Water Temperature Keeps Fluctuating.
  6. Conclusion.
Takedown request   |   View complete answer on applianceanalysts.com


Why is my hot water temperature fluctuating?

One thing that can cause your water temperature to fluctuate is the source itself, your water heater. Your water heater is a good place to start. Water heaters typically last 12-15 years, so if it is getting on in years, it may be time to replace it. It may simply be in need of some maintenance.
Takedown request   |   View complete answer on rooterhero.com


What temperature should you set your tankless hot water heater?

You'll want to shoot for 100-115 degrees Fahrenheit for your water to be heated. If your groundwater temperature is 60 degrees and you want your shower at 110 degrees, that's going to be a 50-degree rise.
Takedown request   |   View complete answer on anthonyphc.com


Why am I not getting hot water from my Rinnai tankless water heater?

If you find you're not getting the hot water you need, start by lowering the temperature setting on your tankless water heater by a couple of degrees. It's counterintuitive, but it affects the hot/cold mix ratio and will activate the tankless water heater unit for lower-flow fixtures.
Takedown request   |   View complete answer on rinnai.us


How long does it take to get hot water with a tankless water heater?

Instant Hot Water

Tankless units take about 15 seconds to bring water up to temperature, but you still have to wait for that hot water to arrive at your shower head or faucet, just as you do with a tank-type heater.
Takedown request   |   View complete answer on thisoldhouse.com


Why is my shower not running hot water?

First, find the shut off valve for the hot water and see if it's closed. If so, opening the valve could remedy the situation. But if the water still remains warm for only short periods of time, you may have a blockage or obstruction in the pipes or a problem with your bathroom shower valve.
Takedown request   |   View complete answer on haldemanmechanical.com


Can you run out of hot water with a tankless water heater?

Endless Supply of Hot Water

The tankless water heater is—you guessed it—tankless! Because there's no tank, it doesn't work off of capacity; it works off demand. A tankless water heater heats up water as you need it, and it brings hot water to your appliances quickly—and never runs out.
Takedown request   |   View complete answer on morrisjenkins.com


Why does my shower take so long to warm up?

There are several reasons; the distance from the water heater, the diameter of the piping, and the flow rate of the water. The further the hot water has to flow, the longer it takes to heat up the shower faucet. This is especially true with a larger home.
Takedown request   |   View complete answer on bonney.com


Why does my electric shower go hot and cold?

If your shower is going hot and cold, it's usually caused by not enough water getting to the shower. So first of all check that the valve coming into your house is fully open and the valve on the line to the shower is fully open.
Takedown request   |   View complete answer on showerdoc.com


Why do I have hot water everywhere but the shower?

If you're getting hot water everywhere but your shower, it could be that your anti-scald device is set at too high a limit. Anti-scald devices (also called a “hot limit stop” or “rotational limit stop”) are safety features that most faucets have.
Takedown request   |   View complete answer on plumbingtoday.biz


Why am I getting hot water everywhere but the bathtub?

Old pipes sometimes get clogged with mineral deposits due to chemical imbalances in the water. This can block hot water from reaching the bathtub faucet, even though the sink's hot water faucet is working fine. A clogged pipe may be the culprit if you replace the faucet and still have no hot water.
Takedown request   |   View complete answer on hunker.com


How often should you flush your tankless water heater?

Over time, a tankless water heater may accumulate mineral build up which can erode the walls inside your tank's heating chamber. To properly maintain and clean your tankless water heater, it's important to flush those mineral deposits at least once a year.
Takedown request   |   View complete answer on rinnai.us


How do I know if my tankless water heater is bad?

Signs Your Tankless Water Heater System Needs Repairs
  1. A drop in hot water pressure. ...
  2. Lukewarm water. ...
  3. The water heater keeps shutting off. ...
  4. Unusual behavior from other appliances. ...
  5. Leaks.
Takedown request   |   View complete answer on tempriteclimatesolutions.com
Previous question
How rare is an INTJ female?