Regardless of what type of heating system you own, you should always have it inspected and cleaned by a qualified and licensed contractor on a yearly basis. This will ensure that your unit continues running for years to come and operates with as few problems as possible.
Especially important in the case of hot water heating systems, having your equipment cleaned once a year may seem costly, but will actually save you money. A dirty boiler causes your monthly power bills to rise significantly, making it more expensive than paying for a single service call. Additionally, your contractor is likely to catch any small repairs that need to be done, before they turn into large problems that can seriously compromise your system.
While having an annual inspection performed on your hot water heating system will help to ensure that things run smoothly and prevent a great deal of problems, it's also important to keep your eye on the system as well, ensuring that all goes well between your yearly inspections. One of the most important things you can do is simply monitor and gauge the pressure in the boiler. In fact, monitoring the pressure on your boiler is probably all you will ever need to do to maintain the system, other than having a professional come out to inspect and clean it once a year.
In the case of most hot-water heating systems, there is only a single gauge to read. This gauge usually measures the pressure, temperature, and the height of water in your unit, otherwise known as the altitude. Keeping an eye on this gauge is very important because a boiler may be seriously damaged or even become dangerous if the pressure inside it exceeds 30 pounds. Optimally, most boilers only use about 12 to 15 pounds of pressure.
TIP: Our HVAC/plumbing consultant Wayne McCarthy adds, “Usually boilers have a sight glass that tells you the water levels. It is a vertical glass tube. Your boiler should have a low water cut-off installed for protection. This control shuts off the unit when water levels are low, usually indicating a leak or faulty air bleeder.”
Sometimes, excess pressure may be the result of a waterlogged expansion tank. You may be able to resolve this yourself, simply by draining the excess water from the expansion tank. Look for a cylindrical tank with a drain valve at one end, commonly located near the boiler, usually overhead. To drain this tank, turn off power to the unit, turn off the water supply feeding the tank, and give the boiler some time to cool down. Once you're sure that it's cooled down, attach a garden hose to the valve and open it, draining off the water until the meters for both the boiler and the expansion tank match. Close the valve, remove the hose, turn the power back on, and re-open your water supply.
If your system is regulated with a diaphragm expansion tank, you may need to recharge it from time to time, should pressure become too strong. Using an ordinary tire air-pressure gauge, you can determine whether the tank is in need of more air. You can add air, as needed, with the help of a simple bicycle pump. Since most are different, check your tank to see what the correct psi pressure reading should be for your particular diaphragm tank.
TIP: Wayne suggests, “If your diaphragm expansion tank is saturated, it probably needs replacement. Charging it with air may be a temporary fix, but you might have a hole in your diaphragm.”
Once your expansion tank has been drained or your diaphragm tank has been recharged with air, restart the system and monitor it very carefully. If the pressure raises, once again turn the system off and call a professional immediately. Be forewarned that a boiler with more than 30 pounds of pressure can explode, so be sure to take precautions if you find your pressure is above normal.
Wayne McCarthy, plumbing and HVAC professional contributed to this article.