Rheem Tankless Water Heater Code 14

Rheem Tankless Water Heater Code 14[How To Fix]

Why does my Rheem tankless water heater display the error code 14? Your tankless water heater will throw this error message when the Overheat Film Wrap is at fault. And the Overheat Film Wrap gets activated if the heat exchanger gets too hot. 

Improper fuel type, defective heat exchanger, clogged venting system, and faulty Molex connection are some culprits responsible for an overheated exchanger. And guess what, your heater will show this error code when the Overheat Film Wrap senses the heat exchanger and finds it too hot. 

Below, we will break down each of the culprits that cause the Overheat Film Wrap to get activated. So, stay in tune with us and explore the way of clearing the error code 14. 

Table of Contents

What Does Error Code 14 Mean On Rheem Tankless Water Heater?

Error code 14 means Overheat Film Wrap gets activated. If there is any hot spot created on the heat exchanger, it will cause the Overheat Film Wrap to fail. 

Overheat Film Wrap is a sensor. It’s a plastic film wrap with the black squiggly lines. It will detect the heat exchanger when it gets overheated. This sensor constantly monitors the temperature of the heat exchanger and will throw an error code 14 if the heat exchanger gets too hot. 

Rheem Tankless Water Heater Code 14: Reasons & Solutions

Don’t know why your tankless heater shows the error code 14? Then, keep reading till the end. 

01. Improper Fuel Type

Every water heater including Rheem Tankless Water Heater uses natural gas or liquid propane gas as its fuel. You can’t use both these fuel types together. If you do so, it will cause a combustion issue, heat the water intermittently, and throw the error code 14. At the same time, some water heaters recommend a specific gas type like natural or LP. 

To avoid this issue, we recommend you check the manual and use the gas type according to the manual. If the manual recommends using natural gas, go for it. Otherwise, use the LP gas to power your water heater. 

02. Heat Exchanger Issue

The heat exchanger is responsible for raising the temperature of your water heater. It’s a device that transfers heat from one source to another. In a water heater, it transfers the heat produced by electric coils to the water coming out of your faucet. If it gets broken, cracked, or covered by dirt buildup, it will get too hot and throw the error message 14. 

As the heat exchanger is prone to get dirty, take an eye to it first. If it gets filthy, remove the dirt from the heat exchanger. On the other hand, if it gets cracked, we recommend you replace it with a new one. 

03. Exhaust Venting Gets Clogged

Like other water heaters, the Rheem tankless water heater has a venting system. Every water heater venting system uses a duct or pipe. It is also known as flue or chimney, which expels exhaust gasses out of the house. 

If the venting system gets blocked by dirt, debris, or insects, the harmful gasses fail to go through the pipe. Consequently, it raises the temperature and causes the heat exchanger to get too hot. 

To avoid this unwanted heater issue, inspect the venting pipe for a clog. If you find any blockage, run a plumbing snake to get rid of the clog. 

04. Defective Molex Connection

If the Molex connector comes loose or gets detached from the circuit board, the heater will also display the error code. 

So, make sure the Molex connector doesn’t come out at location U. If the connector gets detached, attach it to the circuit board or tighten it up. 

On the other hand, if the Molex connector is in its place, check the resistance of the connector. Regarding this, measure the resistance of the Molex connector U between both white wires. The resistance should be 50k-500k ohms. Otherwise, you should replace the unit. 

In contrast, if the resistance of the Molex connector is ok, we bet the PCB gets defective. So, replace it with a new one. 

Relevant: Rheem Tankless Water Heater Error Codes


How do I reset Rheem error code 14?

To reset error code 14, turn off the power to the unit, wait 30 seconds, and restore power to your water heater. However, it’s a must to resolve the underlying issues that cause the error code 14 to pop up. 

How can I prevent error code 14 from occurring?

Perform maintenance workflows like water filter cleaning, flushing the unit, and removing any blockage from the vent system regularly. You can read this guide on Rheem Tankless Water Heater Maintenance to learn how to maintain your water heater. 

Can I resolve Code 14 without professional assistance?

If you’re handy, those troubleshooting steps I mentioned will help you reset the error code 14. However, if you’re not technically inclined, call Rheem Customer Service or a certified technician for help. 


Rheem tankless water heater will display the error code 14 when the Overheat Film Wrap (a sensor) gets activated. If the heat exchanger gets too hot, it will cause the Overheat Film Wrap to fail. Cracked or broken heat exchangers, using improper fuel type, and clogged venting systems are the reasons behind an overheated heat exchanger. Fortunately, we broke down every possible culprit responsible for the activation of the Overheat Film Wrap. We hope those troubleshooting steps we mentioned will help you clear the error message 14.

Similar Posts

Leave a Reply

Your email address will not be published. Required fields are marked *