![](/images/new-backgrounds/1010201/102017x1.webp)
Product Overview
The model is a
The unit draws in fresh, outdoor air through a filter bank in the bottom of the unit and it then moves upward through a combustion chamber or through an optional burner bypass damper. A blower mounted in the top of the unit then forces the air into the building ductwork.
Airflow Arrangement
The unit can be ordered in a number of different configurations to provide 100% outdoor air or 80% recirculated air and 20% outdoor air. These units can also be ordered with a variable air volume (VAV) capability for flexibility in response to building air handling needs.
100% Outdoor Air
If the unit is configured only for 100% outdoor air, it draws outdoor air as needed through the filter bank at the bottom. The air moves upward through the combustion chamber and then it is blown into the building through
80/20 Recirculated Air
When the unit is used as a primary heat source for the building, the unit will draw 80% of the needed air from the building and mix it with a minimum of 20% fresh outdoor air. Outdoor air is drawn through the combustion chamber and then mixed with the indoor air after the
Variable Air Volume (VAV)
The VAV function can be selected when the outdoor air volume required by the building varies. This requires the installation of one bypass damper and selection of an appropriate motor/blower control system. This may involve installation of a Variable Frequency Drive (VFD) controller. Both bypass damper and VFD are factory installed.
4Model VSU
Subassemblies
Filter Section / Vertical Mounting Stand
The filter section of the unit is factory installed in the mounting stand and shipped ready for installation on the concrete mounting pad. Each filter unit has a large access panel on the control end of the unit except for the housing size 50, which has an access door on both ends. Filters are either 2 in. thick pleated paper or 2 in. thick permanent metal type. Filters are changed by removing the access door(s) and sliding the filters in or out on their tracks.
The unit’s vertical mounting stand is fabricated of
Optional Service Platform
A service platform is available
for permanent
attachment to the mounting stand. The platform
is shipped unassembled and requires field assembly. It is attached to the vertical mounting stand
by installing bolts with spacers between the two assemblies. The service platform should be attached to the unit only after the burner and blower assemblies are permanently set in place.
®