Hot Water Unit Heater Protecting a Mechanical Room

Unit heaters are used in various places to protect equipment and provide comfort to occupants. This hot water unit heater provides protection for a mechanical room where there is a large air handler and other associated equipment in the mechanical room. This system is controlled by DDC. A thermostat on the wall detects the temperature of the mechanical room. The DDC system will maintain a temperature set point by energizing the hot water unit heater fan and modulating the hot water valve open on the hot water piping. The actuator and hot water valve can be seen in this photo on the right lower half of the system. The valve is a two position valve so it is either open or closed with no modulating the valve on the unit heater. Other unit heaters for heating mechanical rooms or providing comfort include electric units heater when hot water is unavailable, gas fired unit heaters when gas (either propane or natural gas) is available, and infrared heaters typically found in large garages or warehouses for basic comfort of workers in those spaces. There are also steam unit heaters that utilize steam and a steam coil for heating spaces where steam is available. Most unit heaters are forced air unit

Steam UH

heaters that will blow air across a coil, electric heat strips, or a heat exchanger (gas furnace) and blow the heat into the space. The above steam

unit heater is used for heating a space in a large sleeping room. Gas fired unit heater used in a storage closet where water pipes need protection from freezing. This electric unit heater is used in a mechanical room to protect HVAC equipment and piping from freezing.