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Why Does My Hot Water Turn Cold After a Few Minutes? A New Jersey Tech Explains.

Sep. 11, 2017
hot water heater troubleshootingSo your water heater used to provide an adequate amount of hot water to keep you content. But all of a sudden, it seems like your home’s hot water supply turns cold a lot faster than usual— sometimes even after just a few minutes of use.

So what’s the issue? Well, if your hot water is suddenly turning lukewarm/cold after a few minutes, you most likely have a problem with your hot water heater. More specifically, you probably have a bad dip tube.

We’ll explain what the dip tube is and how to determine this is your problem. We’ll also tell you what you need to do in order to fix the problem.

Need a plumber to repair your water heater?  Just contact us and we’ll send one right over.
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How your dip tube should work

In normal operation, your dip tube attaches to the cold water inlet valve and travels down to the bottom of the tank.

where the hot water heater dip tub is located

It’s main responsibility is to push cold incoming water to the bottom of the tank.

Why does it do this? Well, that incoming cold water is heated at the bottom of tank (either by a gas burner or an electric heating element). And, once heated, the water naturally rises to the top of the tank where it’s ready to exit to the tank via the hot water outlet.

a water heater's cold water inlet and hot water outlet

What happens when your dip tube goes bad

The most common reason for a dip tube going “bad” is because it’s disintegrated away (or has started to).

And when this happens, cold water no longer gets pushed down to the bottom. Instead, it mixes with the hot water at the top of the tank. Which means, your hot water supply quickly turns lukewarm/cold.


How to check for a bad dip tube

If you’re unsure whether or not a bad dip tube is your problem, check for these 2 bad dip tube signs:

1. Your water heater was manufactured between 1993–1997. 

You can check the manufacturing date by looking at the water heater’s serial number. If the serial number has 93, 94, 95, 96 or 97 in the 4th and 5th digit, you likely have a defective dip tube. For example, this water heater’s serial number indicates it was manufactured in 1997.

Why? Well, from 1993 to 1997 many manufacturers installed weak dip tubes that were prone to cracking, crumbling or completely disintegrating long before they should have. In fact, in 2000, water heater manufacturers agreed to settle a handful of class-action lawsuits regarding the installation of these defective plastic dip tubes.

2. Small white plastic particles are suddenly clogging your faucets/aerators.

These white particles are tiny pieces of your disintegrated dip tube that have managed to exit the water heater.

Have an electric water heater and don’t think your dip tube is bad? You could have...

A bad lower heating element

Electric water heaters rely on an upper and a lower heating element to heat the water. But the lower element does the majority of the heating. 

So if you suddenly have a shortage of hot water, you’ll want to have a professional inspect (and possibly replace) your lower heating element.

A bad lower thermostat

Electric water heaters have two heating elements (upper and lower) and each element is controlled by a thermostat. But if that lower thermostat stops working correctly, it could shut off the lower element, limiting your hot water supply. 

Have a professional inspect the unit’s thermostats to see if this is your problem.

Still having hot water problems? Contact a New Jersey plumber

If you’re pretty sure a bad dip tube is causing your sudden lack of hot water, you need a professional’s help.

You see, the only solution is to cut out the remains of the dip tube and replace it with stronger, more resilient material. But you’ll also need a plumber to flush your water heater to get rid of any extra plastic particles floating in your tank.
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