How To Fix Hot Water Coming Out Of Cold Tap

Getting hot water from the cold tap is a bizarre experience. The scalding you get in such situations can stay for a good while. But the thing is, this issue is not that hard to troubleshoot. Want to learn how to fix hot water coming out of cold tap? 

When hot water is coming out of the cold tap, you should first check the location of the pipes. Then, see whether the thermostat requires a replacement or not. And if your faucet has a pressure-balancing valve, get it replaced.

On that note, those are some general steps you need to follow if the hot water is coming out of the cold tap. The issue can be a bit severe, and you might need to go through additional steps. Stick around to get an in-depth idea of the process.

Why Is My Cold Water Hot All of a Sudden

Before discussing the solution steps, let’s first try to understand why hot water is coming from your cold water tap. In general, you might be dealing with one or more of the issues outlined below –

1. Parallel Placement of the Pipes

Do you know the easiest way to differentiate the hot water pipe from the cold one? All you have to do is touch it. It will be piping hot!

Well, when the cold water pipe is parallel to the hot water line, the heat can transfer. That will eventually make the cold water tap give you hot water.

2. Faulty Thermostat

In most cases, the thermostat is the one to blame when there is an issue with the temperature of the taps. Wondering why such a problem would come up? It may have gone faulty and is unable to regulate the water temperature.

That is, the thermostat might be overheating the water, causing the hot water to boil over to the cold water line.

3. Defective Pressure-Balancing Valve

Otherwise known as a pressure-compensating valve, a defective pressure-balancing valve is a common reason why you may get hot water from the cold tap. Wondering what does this part do?

At the core, the pressure-balancing valve maintains a balanced water flow between the cold and hot lines. And when it is functioning correctly, you should get a constant water temperature from each line.

The valve also counteracts the temperature fluctuations that may occur due to high water pressure. But the valve fails to do all of these when it becomes faulty.

4. Faulty Faucet Cartridge

All the modern sink faucets come with a cartridge. Its primary role is to direct the water flow. But when it becomes faulty, you might only get hot water from both taps.

In addition, a faulty faucet cartridge can stop the water flow entirely. That will eventually make you go through the steps to fix a kitchen sink with no water.

5. Poorly Installed Heat Trap

The heat trap needs to be right in the water heating inlet. But when its adjustment or placement is incorrect, hot water can infiltrate the cold water lines. And when that happens, you will not get cold water from the dedicated tap.

How to Troubleshoot Hot Water Coming Out of Cold Tap

Now that you know all the possible reasons why hot water is coming out of the cold tap, let’s get into discussing the troubleshooting steps. Take a look –

1. Insulate the hot water pipe

First of all, turn off the thermostat and close the shut-off valve. Wait for a while and let the hot water line cool down. Afterward, measure the length of the line. You will need this number to work with the insulation material.

Talking of which, common insulation materials include polyethylene foam, fiberglass tape, and neoprene foam. You can choose any of these for this troubleshooting step.

No matter what you choose, cut it according to the measurement you just took and wrap it around the hot water supply line. Finally, secure the insulation material with aluminum foil tape or a wire.

2. Install a new cartridge

Is hot water still coming out of the cold water tap? In that case, you might be dealing with a faulty cartridge. Replace it through these steps –

3. Reinstall the heat trap

Check whether the heat trap is correctly installed near the water heating inlet. And as mentioned earlier, a poor installation of this part will make the hot water get to the cold water line.

But the good news is that you can correct the installation by going through the following steps –

4. Replace the thermostat and pressure-balancing valve

If the problem is still there, the pressure-balancing valve and/or the thermostat have gone faulty. In such cases, it’s better to make a professional plumber take a look at the system.

They will be able to determine which is the root cause and suggest a proper replacement.

How to Replace a Defective Pressure-Balancing Valve

If you are sure that the pressure-balancing valve is the root cause of the issue, you don’t need to call a plumber. Instead, you can replace it on your own through these steps –

1. Close the shut-off valve

As always, you should start by closing the shut-off valve. It will prevent you from getting drenched with hot water and eventually scald your skin.

2. Remove the handle

With the shut-off valve closed, you should work on the faucet handle. Get an Allen wrench and remove the screw on it. Once the screw is off, pull the handle outward to get it out.

3. Take the handle sleeve and assembly out

Remove the plastic handle adapter with a screwdriver. There should be two white pieces of plastic, which you need to pull straight out. But keep them together because you will lose the temperature settings without them.

Next, grab the handle sleeve and take it out. When you take it off, you should see the retaining clips that keep the pressure-balancing valve in place.

4. Remove the old cartridge and install the new one

You should get a plastic adapter with the new pressure-balancing cartridge. Use it to get the old cartridge out. All you have to do is place the plastic piece in place and use a pair of pliers to rotate it.

That should let you get the cartridge to come out partway. Then, use the pliers to grip the cartridge stem and pull it off. With it out, see whether the valve body is clear of debris. If not, use a brush to get all the foreign materials out.

Then, get silicone grease to lubricate the rubber parts of the new cartridge. Insert it into the valve body. Ensure the ‘Hot’ and ‘Cold’ marking on the cartridge face outward. Also, make sure that the positioning of the hot and cold sides is correct.

With all those considered, push the new cartridge towards the stem. Make it go as far as you can.

5. Reinstall the retaining clip and reassemble the handle

For the last step, you have to get the retaining clip back in place and make sure that they are fully seated. With that taken care of, slide the sleeve in place and set the handle. Open the shut-off valve and test the faucet.

Final Words

That’s pretty much everything you need to know regarding how to fix hot water coming out of cold tap. As you can see, the troubleshooting process is not that hard to follow.

And you will only need to call a plumber when there’s an issue with the thermostat. That said, if the hot faucet has no water after all the steps, you might have misadjusted some parts. There could be other reasons too.