Tips for maintaining a steam heating system

If you have a steam heating system in your home, you should know it requires extra attention. But these tips will help make it a little easier to maintain your system.

• Steam heating systems require a special level of care: The combination of high temperatures and contents under pressure can be a dangerous one (that's yet another reason why that professional annual maintenance check is important). But once the mercury drops, there are a few tasks you should perform to make sure that you stay warm all winter.
• With the boiler cycle off, check the system's glass water-level gauge every 10 to 14 days. If the water is below the halfway point on the gauge, turn off the boiler system and give it an hour or so to cool down. Then open its water-supply valve until the water level reaches the ideal zone, between about halfway to two-thirds up the gauge. Why is this important? Your system's water levels need to be within a certain range for the boiler to work. If it falls below the recommended range, the boiler can overheat and sustain damage or even explode.
• If the water does fall below the recommended range, your steam system's low-water cutoff will shut off the burner. Sometimes the burner will shut off not because the water's low, but because sediment buildup clogs the cutoff. It's important that this cutoff mechanism works. Here's how to flush your low-water cutoff:
• First, turn down the thermostat and put a bucket under the pipe. Open the cutoff's drain valve and let water run out until it's clear (be careful, it will be very hot!). Then close the valve, and refill the boiler to its proper level.
• Once a year, test the boiler's pressure safety valve. With the boiler running, pull up the valve's lever and let a little steam escape. If the valve reseals without leaking, it's okay. If it clogs or sticks, shut off the power to the boiler and have the valve replaced.

• Radiator knocks are the bane of one-pipe steam heating systems, in which steam flows to radiators and condensate (that is, water) flows back to the boiler via the same pipe. If the radiator doesn't slope down toward the inlet valve and the pipe doesn't slope down toward the boiler, water collects in the system and impedes the flow of steam, creating a lot of noise in the process. Adjusting the pipe is a job for a plumber, but quieting a radiator is simple.
• Some units have height-adjustment bolts in the legs on the end opposite the inlet valve. Turn the bolts with a wrench to increase the radiator's slope. If your model doesn't have adjustment bolts, slip shims under its legs.
• Another way to prevent knocking in a one-pipe steam system is to keep radiator inlet valves either fully open or fully closed. A partially open valve allows water and steam to mix, which causes the knocking.