Proper Radiant System Design Aids Troubleshooting
“When we install radiant heating systems, we receive a lot of positive feedback — especially when the system is working well,” said Alan Deal of Performance Engineering Group, Garden City, MI. “When there are problems with the system, we don’t always find out. However, those unhappy customers will tell 10 others about the experience.”
Deal said that a lack of understanding about the system and its operation might be one of the reasons for dissatisfaction. He said the typical system uses radiant heat as the primary heat source 90% of the time, with the remaining 10% coming from forced air.
“The customer may be relying on forced air because of a possible miscalculation, and they may be using an incorrect setting,” he said.
“If they don’t know the intention of how it [the system] is supposed to work, they may not know what needs to be fixed.”
Cutting Down On ConfusionDeal believes that an ounce of prevention — proper system planning — is the cure. He said that a properly designed system, by professional engineers, would prevent problems in the field. For example, some of the system components that need to be adequately identified and illustrated include the tubing layout, the distribution piping, and the types of floor coverings to be used. Proper heat loss calculation and an electrical schematic are essential as well.
Deal stressed that proper heat loss calculation is essential to radiant system functionality. This is especially true when heating side-by-side rooms with distinct differences. For example, one room may be a small kitchen with a very small window and, thus, a small heat loss. The room next to it may be high-vaulted, with very deep carpeting and lots of high glass windows, and therefore a high heat loss.
“There could be problems if these rooms are set on the same thermostat,” Deal explained. “Before installation of the system, you have to ask questions regarding the floor coverings, windows, etc. If you don’t ask, there may be trouble later on.”
The same careful planning involves tubing/piping layout, too.
“Leave a paper trail with the tubing layout,” he said. “The designer must take a set of blueprints that shows where the tubing is located. When the tubing is covered up, a clear layout will aid if someone else has to fix problems down the road — and troubleshooting will be easier with blueprints, too.”
Make sure that blueprints are kept up-to-date. Deal cited instances where an original blueprint was followed, but it was discovered that the original installer made additional changes and never got around to noting the changes on the blueprints.
Deal, whose mechanical engineers design plans for every aspect of radiant heat installation, said that making full sets of blueprints up front might be time-consuming, but it’s necessary.
He added that other problems regarding proper system designs include component selection and compatible floor covering materials.
“The heat pump needs to be compatible with other system components, for example,” he said. “A large pump may be big enough for the entire system, but it may be too big and cause other components to malfunction.”
Deal said the other issue — floor covering — should be identified in the planning stages, too. “Before any installation begins, it is important to know what [type of covering] will be put on the floor,” he said. “Radiant works best with no type of floor covering, making it easier to heat a room without carpeting, for example.”
Assessing ProblemsDeal said there are four types of trouble that prevent ultimate heat transfer: too much heat in one room, too much heat in the entire house, too little heat in one room, and too little heat in the whole house.
He said contractors should look at different areas of the home to assess individual problems. Poorly fitting or cracked windows and doors can result in excessive heat loss, as will poor insulation. Excess heat could be the result of a lot of glass on the south side of a home.
“Your system could be perfect, but the building you are working on has constraints, and you can’t get around them,” Deal said.
He recommended contacting the Radiant Panel Association (www.rpa.org) and asking about documents addressing potential problems with radiant heating systems and how to troubleshoot them.
Vatcher is a freelance writer based in Plymouth, MI.
Publication date: 05/07/2001