SELECTING A HEATER
The facts:
The most common error our customers have made in the past is overlook the air projection and how their production, products and daily activities affect their environment.

Most select a unit heater based on steam pressure and BTU/hr. only. We have found that 50% of the existing units installed in North America to be correct in BTU. for the building in theory only.

Selecting a unit based on BTU/hr. only can work in a building that has no air movement, but there is no guarantee the air projection will be strong enough or hot enough to reach the floors.

There are problems with installation of this type, if shipping doors are open for an extended length of time there will be moisture build up on the floors making conditions very dangerous for lifts. Another minor problem is the units will run for an extended amount of time.

Unit selection:
Please consider the following:

1- Projection
You must determine where you want the air. Take consideration of the negative pressure from the ventilation system. When doors are opened the effects are the same as wind tunnel. You must select a projection adequate enough to combat the air penetrating your plant.

2- Final air temperature
Take into consideration your existing air temperature. For space heating in general, with a cold room, consider the temperature you want on the floor. If the temperature range in this room is from 40°F. to 50°F. keep in mind the air from the unit is going to blend with the existing air. If the unit’s air temperature is not hot enough the end results will be cold air and the unit will run constantly.

3- Shipping doors
For plants that have a high negative pressure we recommend units with a high Cfm. and final air temperature. A final air temperature of a 145 F.° for unit heaters is considered a very high. Keep in mind, it will blend with the cold air being pulled into the plant. A high velocity nozzle is one option we offer to combat the cold and air penetration.

4- Trains, trucks and cargo
During the winter months vehicles are loaded and unloaded with cargo bays. These vehicles and stock are the same as large blocks of ice. Units must be selected to fight the cold being introduced into your environment.

After selecting units with the information above, you will find the total BTU. to be higher than
conventional calculations dictate, however, regardless of the results of the calculation the above selections must be considered to select the correct units for your application.