Hydronic water unit heaters heat a space by moving air across a coil fed with hot water or glycol from a boiler. This collection lists Reznor UWS suspended hot water unit heaters rated 15,000, 21,000, 31,000 and 62,000 BTU. They are commonly used in garages, workshops and warehouses. Match the BTU output to the space and the supply water temperature from your boiler.
Hot water unit heaters for garages, shops and utility spaces heated by a boiler. The collection includes Reznor UWS suspended hot water unit heaters from 15,000 to 62,000 BTU.
Output depends on entering water temperature and flow, so check the rating table at your boiler supply temperature rather than using the nominal number alone. Confirm pipe connection size, fan motor voltage, mounting height and clearances. Plan for isolation valves and a thermostat or aquastat control, and protect the coil where freezing is possible.
Calculate the heat loss of the space, then choose a model that covers it at your design water temperature. The BTU number in the title is the nominal rating.
What do I need to install one?
You need a boiler loop with supply and return piping, a thermostat, and power for the fan. Check the installation manual for clearances and mounting.
Is a hydronic unit heater the same as a gas unit heater?
No. A hydronic model has no burner; it takes heat from your boiler's hot water loop.
