Not having access to hot water in the shower is an extremely annoying issue, especially if there seems to be no problem with hot water in the rest of the house.
The first possible issue that comes to mind is a faulty water heater, which is often the case.
However, if there happens to be hot water in the sink and everywhere else, the problem is in the shower itself.
In this detailed guide, we will explain all the possible causes behind this issue and, of course, the best solutions for this problem.
Why is there no hot water in the shower but hot water in the sink
Before focusing on solutions, it is necessary to get to the bottom of the issue and discover what is causing it in the first place.
In case you’re getting hot water in the sink but no hot water in the shower, there are a few possible problems that you should look into before you try any methods to fix it.
This way, you’ll save a lot of time and effort, but also avoid making the process even more complicated.
Without further ado, here are the most common issues behind the absence of hot water in the shower.
1. Faulty anti-scald device
Let’s start off by defining the anti-scald device, which plays a very important role in water temperature management.
The anti-scald shower valve, also known as the thermostatic valve, regulates the temperature of the water in the shower, so you don’t have to adjust it all the time and get shocked by hot or cold water in the process.
This kind of device is extremely important in households with children, as it protects them from painful scalds.
Since the usual setting of the water heater is 140 degrees F, which is hot enough to cause some serious injuries, it is necessary to have a functioning anti-scald device in your shower.
The anti-scald device allows you to have the water hot enough to enjoy your showers and prevent the bacteria from spreading while protecting you from third-degree burns that could occur if your water heater remained set at 140 degrees.
That being said, if you notice that there’s no hot water coming from the shower faucet, but there is hot water in the sink, it is possible that you’re dealing with a faulty anti-scald valve.
2. Wrong setup of the anti-scald device
If you’re getting no hot water in the shower, it doesn’t necessarily have to mean that the anti-scald is damaged or not functioning properly.
Another possibility is that it hasn’t been adjusted properly, especially the water temperature limit.
While it is extremely important to set an adequate limit on your anti-scald valve so you don’t get blasted by hot water, it is also important not to set the limit too high, as you won’t be getting any hot water.
Luckily, the anti-scald device can easily be tested and re-adjusted if this is the issue.
3. Faulty shower mixing valve
A shower mixing valve, also known as a mixer shower, has a very important role in mixing your hot and cold water in the shower to achieve the desired temperature.
What is extremely important about the shower mixing valve is that the actual mixing occurs before the water reaches the showerhead, which simplifies the entire process and makes it much more enjoyable.
Now, for the shower mixing valve to properly mix the water and manage the temperature of the water that comes out of the showerhead, it is necessary for both the hot and cold water to be at the same pressure.
In case the external water supply is shared between different appliances in your home, including your shower, sink and toilet, this could interrupt the stream of hot water and jeopardize the function of the mixing valve.
Modern thermostatic mixing valves, however, rarely cause such a problem, as they automatically adjust the parameters to get a consistent water temperature.
However, both older and newer shower mixing valve models could experience defects, which is one of the possible reasons behind the lack of hot water in your shower.
4. Faulty pressure-balancing valve
Both hot and cold water sources are usually fed into the pressure-balancing valve, which manages and balances out the two water sources, creating a consistent water temperature.
The main role of this valve is to control the water volume, even if there are certain issues with the pressure of the water sources.
This basically means that, even if the temperature of the water source isn’t consistent, you should still be getting a constant flow of hot water.
If that’s not the case, it could be that you’re dealing with a faulty pressure-balancing valve that is cutting off the supply of hot water in your shower.
How to fix no hot water in the shower but hot water in the sink
As we’ve mentioned, the first step to fixing your shower permanently is to inspect it and ensure that all of its components and supplies are working properly.
Any damaged or malfunctioning elements should be repaired or replaced immediately, as you don’t want to risk hot water appearing all of a sudden, especially if the temperature limit hasn’t been adjusted properly.
Needless to say, if you were unsuccessful in detecting the core issue, or you simply don’t feel equipped enough to tackle it on its own, it is always better to contact a professional and have your shower fixed.
On the other hand, in case you were able to pinpoint the problem and you already have some experience in dealing with similar issues, here are the best methods of fixing the hot water supply in your shower.
1. Inspect the anti-scald device
The only way you can know for sure if you’re dealing with a faulty anti-scald device is to troubleshoot it and test if it’s indeed not functioning properly.
The first step would be to set the temperature all the way to the maximum setting, which is usually done by turning the handle all the way to the left or forward, depending on the model.
Then, take off the handle covering the temperature control knob by pressing and lifting the tab or the edge of the cover.
There could also be a screw that you can easily remove with a screwdriver.
Once you remove the protective cap, you should be able to access the adjustment mechanism of the anti-scald device.
Make sure to keep an eye out for any visible defects in the mechanism.
Make sure you also inspect the thermometer.
You can test it by sticking it in a bowl of hot water to ensure that the bar is showing the actual temperature of the water.
2. Adjust the temperature of the anti-scald device
In case you detect no defects on your anti-scald device, and you also confirm that the thermometer is showing the correct temperature, you may want to check the maximum temperature limit.
Once again, it is necessary to remove the protective cap or head from the faucet, which may require a screwdriver or an Allen wrench.
The anti-scald device should be located under the faucet head.
Turn this device to the right and pull it forward slightly, which will readjust the level it’s currently on.
Turn the valve a little bit to the right, which should lower the temperature limit.
Push the device back into place and put the protective handle back on.
Test the shower and check if there is hot water now that you’ve readjusted the temperature limit.
3. Inspect the shower mixing valve and the pressure-balancing valve
One of the possible problems behind the lack of hot water in your shower, as we’ve explained, could be a faulty shower mixing valve.
The first step to inspecting and potentially removing a faulty shower mixing valve would be to remove the protective cap covering the shower valve handle and then to remove the handle and the plate from the shower wall, as well.
Turn the screws located on the shut-off valves to the right to stop the water flow and then remove the cap from the valve by pulling it from the valve.
You also want to clean out the pipes by flushing all the dirt and debris out.
You can do so by opening the shut-off valves just enough for the debris to get flushed out.
This step alone could help in getting your hot water back, so you may want to test your shower after completing the flushing process.
However, if you’re certain that the pressure-balancing unit in the mixing valve is defective, you can proceed to replace it.
Position the O-rings into the new pressure-balancing unit.
The pressure-balancing unit should now be inserted into the valve, making sure you align the key inside the valve with the notch.
Insert the valve into the shower wall.
Then, secure it with a mounting plate and brass screws.
Open the water shut-off valves before positioning the handle back into place.
Paul Wilson is a highly skilled plumber with over ten years of experience in the industry. He holds an IDPH license and takes pride in his ability to tackle many plumbing issues and successfully complete even the most challenging projects.
