After a few calls from homeowners regarding ceiling protection kits and switches, I decided to jot down a few notes to for you! I was surprised to find little information about them on the Internet. You would have to know the name brand to look it up and understand what they do.
First of all, they are used in split system HVAC applications and water heater drain pans located in an interior space. What is a split system HVAC applications? Basically, you have a main unit on the outside of the home and a main unit on the inside of the home. The outdoor unit has a coil, compressor and is usually referred to as the condenser. The indoor unit is either an air handler with a coil, fan motor and auxiliary heat kit (emergency heat) or a furnace and coil. (For more information on types of equipment, click on the link.)
The main indoor unit is where a ceiling protection kit or switch will be located. It is a device that fits on a drain pan and is wired to the unit. The device has a buoyant component which “floats” as water begins to rise in the drain pan. Once the buoyant component floats to a certain point, the switch or kit turns off the main indoor unit. So basically, it is a floating off switch.
Why does a drain pan fill with water? This question has many answers and it can happen for many different reasons. Air handlers Air handlers are typically fitted with a redundant yet necessary secondary drain pan. (also referred to as a emergency drain pan.) If the primary drain pan becomes clogged, the water overflows into the secondary drain pan. If the secondary drain pan becomes clogged, the water overflows onto the structure. (Usually a ceiling.) This is where the switch or kit becomes your friend! If the switch or kit is installed in the secondary drain pan, the device will shut off the main indoor unit to limit condensation. It is not full proof, but could be the difference between serious drywall repairs and a bit of paint.
Drain lines become clogged for many reasons. It does not matter if you have your system maintained several times a year. In the winter, they can freeze. In the spring or summer, when condensation is at its max, bugs, critters, creeping grass and insulation have all contributed to “the clog”. In recent years, we have seen many furnaces cause water damage due to condensation. Not because of cooling, but during the bitterly cold. High efficiency furnaces actually produce a significant amount of condensation. While your relaxing and your furnace is silently chugging away, your condensate drain lines are freezing. Literally, freezing from the outside in causing restricted drainage and water to fill up in the drain pan.
I know this is not a technical or extensive overview of a ceiling protection switch, but hopefully you get the gist of it. I added a couple of links that might explain the component a bit better. I wanted to give those out there an overview beacuse there is limited information unless you know what you are looking for. I also included alternate names these components may be referred as.
Alternate Names: Ceiling protection kit, ceiling protection kit, aqua-guard, float switch, condensation shut off switch