Single wall flue vent used on an atmospheric boiler.

Single wall flue vent used on an atmospheric boiler.

Automatic Vent Dampers | HVAC Energy Efficiency - Everyone wants to get the most out of their equipment whether it be for heating and cooling or anything else. If we can save a few bucks every month then it’s good we saved that money and energy for the future.

This article is applicable to those people with gas or oil furnaces, gas or oil boilers, and or gas or oil-fired water heaters. Basically, any appliance that burns fossil fuels and has a flue through a vent or a chimney this article is applicable to you and can save you money by saving energy. 

Automatic Vent Dampers | Powered or Non-Powered

If your appliance is new it probably has this feature on it and depending on whether you bought the Cadillac model or the economy model will likely depend on whether the automatic vent damper is powered or not powered. It is also important that the automatic vent damper is installed by a professional because if installed incorrectly it can cause health issues and even death so take it seriously and allow the professionals to install the automatic vent damper for your heating system.

Some automatic vent dampers come with a little motor that powers them open and closed at the correct times. These powered systems have a safety interlock to prevent that will not allow the heating systems to fire if the automatic vent damper is not open. The manual or non-powered vent dampers do not have any safety interlock unless a thermal kill switch is installed near the draft hood as recommended to prevent flue gasses from spilling into any area where there are people.

Automatic Vent Dampers | How it Works

Automatic Vent Dampers | HVAC Energy Efficiency

Automatic vent damper installed over a furnace. Thanks to D&G ContraServ for the photo

Automatic Powered Vent Damper - When the thermostat calls for heat the powered automatic vent damper gets a signal to the motor to start turning the damper to the open position. As soon as the damper is open a switch closes that allows the burners to begin their sequence of operation to fire the main burners. If the end switch does not close it means the damper never fully opened and the flue gasses will not vent up the flue.

Manual Vent Damper - The manual vent damper has a bi-metal inside that closes off the flue when it cools down. This bi-metal reacts to heat so when the burners fire the heat causes the bi-metal vent damper to open. If for some reason the bi-metal manual vent damper gets stuck and fails to open a thermal switch near the draft hood should open and kill the appliance and prevent it from operating again until the system is looked at by a professional to figure what happened and to make the repair.

Both the manual and the automatic vent dampers save you money by closing off the flue after the appliance shuts down. These dampers prevent heat from escaping up the flue. You paid for that heat so why allow it to escape up the flue after the appliance has shut down?

This can save you money by keeping that heat inside the system and reducing jacket heat losses to the atmosphere. Remember it is very important that a professional install this as there are dangers posed by improper installation or installing improper dampers not rated for this purpose.

Remember, energy isn’t getting cheaper. Saving energy is key to saving dollars and automatic vent dampers will save you dollars in the future.

High Performance HVAC Air Conditioning and Heating Systems

Automatic Vent Dampers | HVAC Energy Efficiency