How Do Steam or Hot Water Furnaces Work?

Peace of mind occurs when it is cold, and a homeowner wants to turn up the heat. By pushing a couple of buttons, the temperature increases in the living room or whatever space they’re in at the time. However, how does a furnace run by steam, or water really work?

Heating a home can be done with a hot water or steam boiler. Both use gas or oil to fuel the boiler. The steam or water travels through the radiant baseboards, radiator pipes or pipes located in the walls or floors. Often, this works like clockwork to heat the home. Unfortunately, it anything goes wrong, a homeowner may need to obtain a free estimate to repair or replace their furnace.

How Steam Furnace Works to Heat a Home

Let’s look at a steam furnace first. A steam heater is one of the oldest convection heating technologies. In fact, it’s been around for about 200 years. They operate like a tea kettle. The water in the furnace heats to a boil. As it heats up, pressure builds. Once the pressure is at its maximum, the water turns to steam. The pressure also pushes the steam throughout the house.

For example, the steam moves through the piping system in a home to heat the home. The steam furnace consists of a one or two pipe system. A single pipe, or one-pipe system is the most common in older homes that haven’t had a furnace update in a while. It uses the same piping to steam the water and collect it after it makes its way through the radiator. The single pipe system doesn’t allow a homeowner to close off the steam to a separate radiator.

The steam travels through the pipes to the valves or vents connected to the radiators. The system pushes the air before the steam travels through the pipes. The air is then pushed out of the radiator vents. This is done through the heating cycle and is called “breathing.”

A two-pipe system is more common in newer homes. It separates supply piping that connects to the radiators. Another piping supply connects to a separate area. The second piping connects the radiators to the furnace. Vents are connected to the furnace, not the radiators. Steam travels from the piping connected to the radiator and pushes the air to the drain on the other side of the radiator.

Using the Thermostat to Set the Temperature

When a homeowner uses their hot water furnace, they turn the temperature lower or higher. When the desired temperature drops from the degree preset by the homeowner, the circuit closes. This means the furnace switches off to allow heating to begin. The water circulates through the closed system and heats up the water as it pushes through the furnace.
The furnace operates differently. It starts when the temperature in the furnace drops below a certain degree. That degree is about 185 F. With a gas fired burner, the furnace has control valves that allow gas to flow into a burner.

If the furnace, has an oil-fired boiler, things run differently. It has an oil pump. The oil pump delivers oil to an atomizing nozzle at a high pressure. This sprays the oil into the fire chamber of the furnace. Fuel ignited with an electric ignitor or pilot light. The furnace goes through a series of steps to heat the water before it is dispensed into the radiators. Once the boiler stops warming the internal temperature sensors show that the correct temperature has been reached.

Maintaining a Hot Water Heater in a Home

Even the best furnaces need a little maintenance. Maintenance may entail draining the boiler or venting the radiators to keep the furnace running efficiently. This also means that hiring a furnace technician is the best option when keeping a water heater working properly. A technician may lubricate the circulating pump motor to maintain the system.

In the autumn and winter seasons, it’s important to purge or vent radiators. This is done for radiators that don’t have an automatic purging system. Preventative maintenance is also important during the spring and fall seasons to prevent a furnace breaking down or needing a repair.

To keep a furnace running smoothly, contact a furnace technician for help with preventative maintenance. If a repair is needed get an estimate to understand what needs to be done to repair the furnace and how much it will cost. Most estimates are free. Thus, a homeowner can compare prices and choose the best technician for the job.