How to Repair a Rheem Furnace Code H

If your Rheem furnace is making strange noises or has stopped working, it may be time to repair the unit. There are several common issues with Rheem furnaces, and luckily, most of them can be easily fixed. Many of the problems are due to user error during installation or simple issues like tripping a circuit breaker. Troubleshooting a Rheem furnace should take no more than an hour unless there’s an underlying issue that you need to address right away. The first step in troubleshooting any problem with your furnace is going through these checklists. If you identify any of the potential problems listed below, read further to learn more about your specific issue and how you can resolve it.

Check the circuit breaker

When installing a new furnace, many homeowners experience issues related to tripping the circuit breaker to the furnace. In this case, the circuit breaker is protecting the furnace from short-circuiting. The circuit breaker trips because the furnace draws more current than the circuit is rated for. To solve this problem, you first need to determine the reason the circuit breaker is tripping. In many cases, the circuit breaker is tripping because the furnace is located in an area without proper air circulation. When this happens, the motor gets overheated and the circuit breaker trips to protect the motor. You can solve this issue by installing a wall or ceiling fan to move the air around the furnace. Another reason a circuit breaker trip is when the voltage of the circuit is too high. This is usually due to the length of the circuit. If the circuit is too long, the voltage may dip below the appropriate level, tripping the circuit breaker. To fix this, you can either add another circuit to the line or shorten the circuit by changing the location of the furnace.

Check for carbon monoxide leaks

A CO leak from your furnace can be dangerous and even deadly. To check for leaks, you can use a CO detector or a CO analyzer. A CO detector is an inexpensive tool that is widely available at hardware stores or online. Make sure the detector is CO-specific and has a digital readout. CO analyzers are a more expensive option, but they can be used to test the CO levels at various points in the house. A CO leak can be caused by many things, including a clogged filter, a bent or broken blower wheel, incorrect pressure settings, a clogged burner tube, or fuel leakage at the fuel valve. To fix a CO leak, turn off the furnace and call a professional to diagnose and repair the problem. If you have CO detectors installed, make sure they are working correctly. If they are CO detectors, they should go off when the CO levels rise. If the detectors are not sounding an alarm, the CO levels may be very high in the house. If this is the case, immediately leave the house and contact the fire department.

Confirm there is no gas leak

Natural gas leaks can be dangerous and pose serious health risks. Luckily, they are easy to detect with a natural gas leak detector. If you hear a clicking noise coming from the furnace, this may indicate a gas leak. If you suspect a gas leak, shut off the furnace and call a technician. You can also smell a faint rotten egg smell, which is the smell of burning methane. To repair the leak, call a technician to correct the issue. You may have to have the gas line repiped if the leak is serious enough. Another way to check for a gas leak is to use a tool like an electric spark tester. This device will send an electric charge through the gas line to see if the gas is flowing. Even if the device doesn’t detect a leak, it’s still important to use a natural gas leak detector to be sure.

Check the gas pressure

Gas pressure is the amount of pressure in the gas line. If a Rheem furnace is running but not heating the house, it may be due to low gas pressure. First, confirm the pressure on the gas line is within the acceptable levels (85-135 PSI). If the pressure is correct, there may be a problem with the gas valve. You can reset the gas valve by turning it off and then back on. If the problem persists, you may need to get the valve replaced. Many Rheem furnaces have a pressure regulator that can also cause low pressure. The regulator is connected to the gas line near the furnace. If the pressure is too low, you may need to replace the regulator.

Check for a bad thermostat

If your furnace isn’t running when it should, the thermostat may be bad. If you have more than one heating system installed in your home, you should check both thermostats. To test the thermostat, use a multimeter to check the voltage at the wires connected to the thermostat. If there is no voltage, the thermostat is broken and needs to be replaced. If the thermostat is receiving voltage but isn’t responding properly, you may need to clean the contacts or replace the thermostat. Most Rheem furnaces use a mercury-switch thermostat, and these are very easy to test. Disassemble the thermostat and clean the contacts with sandpaper or a needle. If the problem persists, you may need to replace the thermostat.

Rheem furnace blower doesn’t work

If the blower on your Rheem furnace isn’t working, there may be an issue with the wiring. Start by checking that the circuit breaker is not tripped. If the blower is still not working, you can test the wiring by temporarily disconnecting the wires from the blower and connecting them to a voltmeter. If there is no voltage at the terminals, you may need to replace the blower. If the wiring checks out, you can check the motor by removing the blower and testing the motor with a multimeter. If the motor is bad, you can clean it or replace it. A bad motor may be caused by a clogged filter or bad wiring. Clean the filter and check the wiring.

Rheem furnace fan doesn’t work

If the fan on your Rheem furnace isn’t working, there may be an issue with the circuit breaker. Once again, check the circuit breaker to make sure it’s not tripped. If the circuit breaker is not tripped, check the fan’s wiring. If there is no voltage at the terminals, you may need to replace the fan. If the wiring checks out, clean the fan and test it with a multimeter. If the fan is bad, you can clean it or replace it. It may be clogged with debris or have a bad motor. Clean the filter and check the wiring.


The Rheem brand has been around since 1922, so it’s no surprise they have a wide range of products on the market. Rheem furnaces are some of the most popular gas furnaces on the market, and they have a reputation for being very high quality. If you are experiencing a problem with your Rheem furnace, start by checking these lists of common issues. If you identify any of these issues, you can move forward with the troubleshooting process. It’s important to be patient and persistent when troubleshooting, so don’t feel discouraged if it takes some time to diagnose the problem. With the right tools and knowledge, you can easily repair a Rheem furnace and get the heat back on.