Catalogue

UV-PRC004-EN 15
Application Considerations
Freeze Protection
The most important advantage the Trane blow-thru design provides is additional protection against
coil freeze-up. In contrast, draw-thru configurations allow little mixing of the return and outside air
stream while locating the coil very close to the outside air inlet. This process creates “cold spots”
on the coil which could lead to coil freeze-up.
With a blow-thru design, face and bypass with isolation valve control is not necessary (as with other
manufacturers) to provide proper freeze protection to the unit ventilator. This adds cost and more
mechanical components that could break down. The placement of the coil above the fan allows
enough space for the coil to avoid “cold spots” that could cause freezing.
Figure 4. ASHRAE cycle graph
UV-PRC004-EN.book Page 15 Monday, February 4, 2013 11:01 AM