Will a draft control device allow spillage when there is a stoppage in the vent?

A draft control device is designed to regulate the flow of air or gas through a venting system, primarily to prevent backdrafts and to ensure proper ventilation for combustion appliances. When the vent is stopped, the draft control device's primary function is to respond to changes in pressure and temperature within the venting system.

If there is a stoppage in the vent, the draft control device may not effectively maintain a proper draft, leading to conditions where combustion gases could potentially escape back into the living space rather than being vented outside. This condition, known as spillage, can occur because the device may not close or seal completely under certain circumstances, allowing for gases to leak.

Understanding this, it highlights the importance of ensuring that venting systems are designed correctly and that draft control devices are functioning as intended to prevent such hazardous scenarios. Having a properly installed and maintained draft control is essential to avoid risks associated with spillage, especially during conditions that could disrupt normal airflow.