Photo of a technician adjusting a dial on a heat pump water heater.

Like any appliance, heat pump hot water heaters are bound to have some technical issues over their lifespan. Luckily, because they are a newer technology, their issues tend to be limited. This article will sum up the most common issues that owners of hybrid water heaters face and how to combat them.

Potential issues with your heat pump hot water heater could be water leaking, an unknown error code popping up, a weird odor emanating from the pump or the lack of hot water. You can often fix these issues yourself. But you may need to call in a professional for situations where a fix is not intuitive.

Luckily, with appliances, there is always a solution to every issue. Sometimes, finding the problem is the hardest part! But we’re here to help with all of the steps you need to find and fix your hybrid water heater problems.

Common Heat Pump Hot Water Heater Problems & Solutions

In this section, we will break down some of the most common heat pump water heater problems and their likely solutions. This is a great resource if you currently have a heat pump water heater and are experiencing one of these problems. It might also be helpful if you are looking to expand your research and knowledge before purchasing one! (Check out our other articles if you’re looking for heat pump water heater incentives or wondering where to install one.)

Water Leaking Or Dripping

Water leaking is one of the most common problems people have with not only heat pump water heaters but other water-related appliances as well. Most appliances are not meant to drip water so this is an indication that something might not be quite right.

In the case of a heat pump water heater, dripping water on the exterior of the unit likely means either something came loose or the drain is clogged or dirty. If you notice the water dripping or leaking around any connections or gaskets, then your first step should be to re-seal the connection. If that doesn’t work, then it may be necessary to replace the connection or gasket.

If the water heater’s condensate drain is clogged (or even dirty), this could cause some water to drain or leak. You should do regular maintenance checks on the drain to prevent backups. Keeping it clean, and cleaning it when it is dirty, should stop any unwanted leaking or dripping.

Additionally, there are devices you can buy that will automatically shut off the unit if any leaks are detected. This can prevent any major leaks or water damage to your house.

Lack Of Hot Water

A lack of hot water could mean a few different things. It could be that there simply isn’t enough hot water at any given time, or that the water isn’t hot at all, or just not as hot as you want it to be.

Before worrying about any major problems, ask yourself a few questions:

  1. Is the demand for hot water higher than normal? If you have people staying with you or more people than normal showering or using hot water at any given time, the lack of hot water could simply mean that the water heater cannot keep up. If your water heater is newly installed and you can’t find any other issues with it, the water heater may be undersized for your needs.
  2. Is it winter or significantly colder than normal where you live? If the water coming in is too cold, then the water heater may not be able to keep up. This should only happen in severely cold weather. It could also be that the water is getting heated but the pipes in your house aren’t insulated well. In this case, the water is cooling off in the process of getting from the heater to you.
  3. Were you on vacation or did the mode change? Most hybrid water heaters have a “vacation” or “away” mode. It could have gotten triggered accidentally, or you could have set it that way on purpose and then forgotten about it.
  4. Where is the thermostat set? The thermostat on the water heater may simply be set too low. Double-check to make sure the thermostat is set to the temperature you desire. Be careful, though. If you set the thermostat too high or too low, the pump likely won’t work.
  5. Have you replaced the filter recently? If the answer is no, then check to make sure the filter is clean. If it is dirty, you should clean or replace the filter (depending on the model you have).

If none of these are the case, it is time to delve a bit deeper into the issue.

One potential problem could be a buildup of limescale or other sediments. This would occur in the water heater’s tank or potentially on any of the heating elements. A buildup of minerals on the unit can prevent proper heat transfer from the appliance to the water.

If you have hard water, or water with a lot of minerals in it (typically found in well water), it could be beneficial to install a water softener. This would prevent buildup on the heating elements.

The unit could also simply need to be reset. There are tests you can do on the fuse, circuit breaker, temperature sensor, and power that can help determine if it is an electrical issue within the unit itself. You can utilize your specific manual or manufacturer’s website to learn how to run these tests on your heat pump water heater.

Photo of a faucet running steaming hot water from a heat pump water heater.
It’s easy to take hot water on tap for granted–until something goes wrong!

Water Is Hotter Than Desired

if water is too hot, on the other hand, it can be dangerous. If the water coming from your heat pump water heater is much hotter than expected, be sure to check the thermostat on the unit first. It could have gotten adjusted accidentally.

There are two common issues if the water is too hot: either the thermostat or the electronic control is broken. In this case, it is recommended to call a professional to help fix your water heater.


Hybrid hot water heaters are known for being a bit noisier than their purely electric counterparts. However, if there is clunking or excessive noise coming from the unit, it is worth checking to see if there is a problem.

Most issues related to noise, such as clunking, gurgling, cracking, or popping are usually related to sediment or mineral buildup. As mentioned above, mineral buildup can occur if you have hard water or well water. Water heaters in general are not designed to heat hard water over long periods of time, so the minerals in the water tend to build up on heating elements or in the tank.

If you do have hard water that has caused build-up on the unit, it can be beneficial to get a water softener. The lifespan for a unit with hard water is significantly shorter than those that are installed in areas with water that is not mineral dense.

If the mineral build-up is not the issue, check to make sure that all heating elements, the filter, and the drainpipe are clean. Inefficiencies such as these within the unit could cause unwanted noise. If none of these checks reveal any problems, then it is likely time to call a professional.

Smelly Or Discolored Water

Smelly or discolored water is just not a good situation for anyone wanting to use hot water. For the most part, though, there are fairly simple fixes to these issues. If your water smells like rotten eggs (the most common bad smell for water), it means there is too much sulfur in your water.

Many heat pump water heaters have an anode rod within the unit. Sometimes, high amounts of sulfate in the water can react with this rod, specifically if the rod is made out of magnesium. If this is the case, the heater can be chlorinated to get rid of the smell and a new anode rod can be installed. Anode rods made out of aluminum are the least likely to have a reaction with water that has a high sulfate content.

Discolored water can also be an issue with the anode rod. If you have discolored water, this is the first thing you should check. Sometimes the anode can corrode, which may give the water a muddy brown color. If the water is a milky or white color, it could mean there is a gas buildup in the pipes or system. Installing aerated faucets is an easy way to prevent or fix the build-up of gas.

Picture of a faucet running brown discolored water, indication of a possible problem with a heat pump water heater.
If this is what you see when you turn on the faucet, you’re going to need to look into it!

Heat Pump Blowing Warm Air

If your heat pump, located at the top of your heat pump water heater, is blowing warm or hot air, this is an indication that there is a potential problem. The heat pump should pump out cool air. If this does happen, the simplest answer is that the refrigerant is low and needs to be replenished. It could also indicate that the fan or coils are dirty.

Heat Pump Making a Rattling Noise

If the heat pump itself is making a rattling noise, as opposed to any other weird noises discussed above, it could mean it is time for a tune-up. Usually, it is very simple and something has just become loose within the heat pump over the course of its life. To fix it, you can go in and tighten anything that is loose, and probably check all of the other connections that could become loose over time as well. In other instances, it could mean that something has broken or snapped within the unit.

Troubleshooting & Maintaining Your Water Heater

Here are some basic troubleshooting and maintenance tips for anytime something doesn’t seem right with your water heater. These are pretty simple and are not meant to fix issues, but more to diagnose them.

Error Codes

Sometimes an error code will pop up on your water heater. This could be a simple mistake by the machine, or it could mean something is wrong. One of the easiest ways to determine if the error code is a malfunction is simply powering down the unit and powering it back up. If the error code persists, then it is likely an actual error. Fixes for error codes can typically be found in the user manual or on the manufacturer’s website. Certain error codes may require that you consult a professional.

Cleaning & Replacing Filters

The air filter is a key piece of the unit and one of the easiest pieces to maintain. The manufacturer should have a recommended period of time for the filter to be replaced or cleaned. Different units have different types of filters. Some filters simply need to be cleaned and put back whereas others will need to be fully replaced at regular intervals.

Drain Pipe Maintenance

The drain pipe or tube is another piece of the water heater that is critical to the unit’s efficient operation and is simple to maintain. Once again, there is probably a schedule for cleaning the drain pipe laid out in the manual or manufacturer’s website. It can be as simple as giving it a check when you walk by. A clogged or dirty drain pipe can cause issues within the unit so keeping it clean is good maintenance practice.


From weird noises to dripping water to bad smells, there are several common issues that may occur in a heat pump water heater. These units are highly efficient, but as with any machine, they may have some issues over their lifespan. Most issues can be resolved or prevented by simple maintenance practices or fixes.

Remember it is important to practice regular maintenance on your unit, just like you would with any other appliance. Additionally, many heat pump water heaters have a nice warranty, so don’t be afraid to consult a professional if the issues persist or you can’t resolve them yourself.

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