Your heating oil system can either be a furnace or a boiler. A furnace refers to the heating unit in a warm air, or forced air, system. After the air is heated in the furnace, a blower forces it through ducts. The warm air is then released through vents or registers in your home.
If you have a hot water (hydronic) system, water circulates around your boiler’s combustion chamber. A circulator pumps the hot water through pipes to heat baseboards or radiators. Eventually, the water returns to the unit to begin the cycle again. If you have a steam system, the boiler turns the water into steam, which then rises through pipes to radiators.
Whether it’s a boiler or a furnace, one important factor in making today’s oil heating equipment so remarkably safe and efficient has been the proven reliability of modern heating oil system controls.
A wide range of limit controls, thermostats and switching relays are used in the operation of heating oil systems. And these controls have become more accurate and sophisticated with the introduction of more technologically advanced equipment.
To help you better understand how your heating oil system works, here is an overview of some of these controls.
The thermostat is the boss; it manages all the other controls to make the heating oil system start working. When heat is needed, the thermostat starts the oil burner through the primary control and an electrical circuit.
Today, many people are using a smart thermostat in their oil-heated homes. A Wi-Fi enabled thermostat allows you to view and change temperature settings from anywhere, thanks to your smartphone.
Once the smart thermostat gets installed, you register it online. This gives you access from any location. If you’re away from home, you can use your phone to adjust the temperature setting so your home is at the perfect temperature when you return. You can also monitor the temperature in your home when you’re away on vacation and call for help if you detect a heating problem.
Read more about smart thermostats.
Limit controls on heating oil systems regulate warm air, water temperature and pressure control. There are two categories: high limit/safety controls and low limit/operating controls.
Primary controls monitor the oil burner’s flame. Solid-state controls and advanced microprocessor-based controls are very accurate. Primary controls also have a reset button that allows you to restart your oil burner (when the power comes back on after an electrical outage, for example).
Additional protection circuits, such as the cad cell (cadmium sulfide photocell sensors) were added to heating oil systems in the 1970s. A cad cell, which is usually mounted on the oil burner, uses its photo cell “eye” to send a shutdown message to the primary control board if it cannot “see” the burner’s flame any more.
There are usually two switches that control the power to the oil burner. A red emergency switch is typically located at the top of the basement stairs. If the heating system is in a utility room, look for the emergency switch near the room’s entrance. A second burner power switch is typically found on or near the heating system.
Read more about heating oil furnaces and boilers.