Tjernlund Products’ new chimney stack assist kit (Model CSA1) allows water heaters to be vented through existing connectors and oversized chimneys. Previously, upgrading to a condensing direct-vent furnace often required installation of a chimney liner for the orphaned water heater. The CSA1 Kit features the use of a mechanical-assist fan to protect against condensation callbacks and flue gas spillage. Installing the kit is a one-person job and doesn’t require an electrician. The kit includes a draft hood linear limit safety to lock out the water heater in case of sustained flue gas spillage. The kit contains all components for the installation.