If your home uses radiant heating, then it's powered in one of two ways: through hydronic plumbing or electric floor pads. Hydronic heating is typically more efficient and common, but it can have its own potential set of problems. Homeowners typically monitor the system pressure to determine if an issue exists, but what can pressure changes tell you?
Most home radiant heating systems operate in a range of around 15psi cold pressure, with some slight variations depending on the water temperature as the system runs. A significant change in pressure may be the result of one of these three issues.
Like any other plumbing, hydronic radiant systems can leak. These leaks usually occur at joints, although corrosion (usually due to an underlying issue with the fill water) can also cause pipe leaks. Any leak in the system will cause the water pressure to drop over time. A significant leak will cause the pressure to fall to 0 psi and create quite a mess, but more subtle leaks may be harder to notice.
If you notice your system pressure running lower than usual, monitor any changes daily. A steady drop in pressure is a sure sign of a small leak. Once you know that a leak exists, stop using the system and call a plumber to locate the problem. Allowing a pinhole leak to persist for even a short time can lead to severe water damage.
2. Expansion Tank Failures
Radiant systems use expansion tanks to allow the fill water to heat without drastically increasing system pressure. Problems with the expansion tank usually manifest as an increase in pressure, although a faulty tank may cause the system pressure to drop or vary randomly. Pay special attention to the relief valve on your water heater, and stop using the system if you notice any significant water loss.
Expansion tanks can fail for various reasons, one issue being with the internal bladder. Tanks can also develop leaks as they age, causing pressure to drop and potentially introducing air into the system. You'll typically need to replace your expansion tank once it begins to exhibit signs of trouble.
3. Air in the System
Air in your radiant heating loop can cause trouble, just as air can be an issue in any closed system. Air may find its way in due to improper installation, leaks, or failures. In addition to a loss of pressure, loud noises are a good indication that your system has an air problem. Bleeding the system may solve the issue, assuming that the extra air is not due to a leak or expansion tank failure.
Monitoring the pressure of your hydronic radiant heating system is an excellent way to spot problems before they become critical. If you notice a change, always contact a heating contractor to resolve the issue and avoid damaging your system or your home. Contact a heating contractor for more information.