Troubleshooting a Radiant Floor Heating System

A radiant floor heating system can be an efficient home heating system. Problems do crop up, however, and you will need to know how to handle them. You should know what type of system you are using: stapled-up, in-slab, gyperate or lightweight concrete. You should also have an owner's manual handy. This will help you compare energy reading from resistors, inform you what flooring materials are suggested for your system and what temperatures are recommended. Without this information you are going into this project blind and won't have enough data to make an accurate determination of the problem. Troubleshooting begins by answering some basic questions.

Floor Coverings

Have the floor coverings been changed recently? If they have, are the materials compatible with the recommended temperature for the broiler? If the coverings have been changed and are within the recommended settings for the broiler, simply adjust the thermostat accordingly. If the coverings are not compatible, you may need to invest in a new broiler. 


Valves are a key element in the heating system. There are three ports on each valve: hot, cold and mixing. Most problems occur in the mixing port, but check each port just to be safe. Water should flow through each port at the right temperature. If it is not, adjust the valve. Compare the water temperature flowing through the valve through the temperature registered on the valve setting. If they are not the same you may need to replace the valve. 


Problems may also be found in the tubing. Metal tubing may become rusty or moldy. These should be replaced. Solo role tubing can usually be treated by flushing the pipes with fungicide or compressed air. These pipes make a good replacement for steel or cast iron tubing. These pipes may become brittle over time. Weigh the pros and cons before you decided what type you wish to use. 


If the floor coverings, valves or tubing are not the problem, you need to check your heat source. A broiler should turn on in cycles. If the broiler is always on, it is too small to do its job adequately. You will also need to check the temperature gauge. Do this while the broiler is warm, not on start up. Write down the temperature of the water leaving the broiler and the water returning to the broiler. There should be a 15-30 degree difference. If there is a difference of less than 15 degrees you simply need to raise the tank thermostat. If the difference is greater than 30 degrees you may need to replace the tank. 


Another good thing to check is the outdoor sensors. These should be located in a shady area. Check the sensors using a resistor. The number of ohms registered should be close to the number of ohms recommended in the owners manual. The numbers will not be exact, but they should not stray far from the recommendations. 


If you cannot find the problem or it is outside your range of abilities to fix, it is time to call in a professional. They are trained to spot small but significant problems.