Meet Zane Zanda

Problems You Can Have With Cast-Iron Boilers

Cast-iron boilers are usually highly reliable and can operate without serious problems for many years. On the rare occasion when some sort of problem does occur, it most often involves sensors, the wiring or the metal body of the boiler itself. If you've noticed a problem with your boiler, you can use the following tips to help you troubleshoot it. That way you know what you want fixed when you call in the professional, like one from Bristol Heating & Air Conditioning.


Over the years, your cast-iron boiler's thermostat might slowly become less accurate. This means that it will either keep your home at the wrong temperature or turn your boiler off and on at the wrong times. If you have a programmable thermostat, it could be that the clock is stopped or the battery might have died. On the other hand, wiring problems (from loose connections and short-circuits to failed relays) can all interfere with the proper functioning of your boiler.

Condensate Pipes

Boilers produce a lot of condensation, and a condensate pipe is installed to drain this condensation away to the outside of your home. But when freezing weather arrives, ice can form at the end of the pipe and cause a blockage. Mold or algae growing in the pipe can also create an obstruction. When either of these two things happens, water will drain back into the boiler and the boiler will automatically shut down. If you have a flashing warning light or hear bubbling sounds from inside the boiler, you may have a blockage in your boilers condensate pipe.

Pilot Lights

Gas-fired cast iron boilers are fitted with pilot lights. If the pilot light on your boiler won't light, this could mean that the vent pipe is blocked. On the other hand, if it lights but won't stay on, this could mean that the flame sensor or the pilot light assembly are dirty and need to be cleaned. Other reasons your pilot light might go out include a bad boiler controller or a bad thermocouple. Another alternative is that you might have a faulty gas valve.

Incorrect Pressure or Temperature

Your boiler could also shut down if the temperature or pressure is either too low or too high. If you have a closed vent or a damaged fan motor, this could cause low pressure. A damaged control board or circulator could cause both high temperatures and high pressure. High temperatures can also result from a malfunctioning temperature sensor.

Boiler Cracks

If you allow your boiler to operate at a very low water level or let sludge buildup inside it, this can cause it to overheat. In turn, this can create cracks. The result will be that when the boiler gets cold, these cracks will let water leak out of the system.

About Me

Meet Zane Zanda

My name is Zane Zanda, and welcome to my site on construction! Although I'm not a professional, I first became interested in construction topics a few years ago when my wife and I were building our dream home. But, interestingly enough, it wasn't the actual construction process that lit the spark. It was actually fire sprinklers. When my wife and I, were talking to our contractor about getting the permits for our house, we were informed that the square footage of our house was so large that we would actually be required to install fire sprinklers in the ceiling! I thought that was so strange, but of course we complied. As I started looking at all the different construction laws, I knew I was hooked.