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Figure 1. |
Operating
Principles |
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During
both the heating and cooling operations, a seal against the ingestion of
contaminated air is formed as follows: Fresh air from the fan discharge is
supplied to point (a) at a pressure slightly above atmospheric. Some of this air flows away from the HVAC
unit; thus, preventing ingestion of outside air. A portion of the air returns to the HVAC
unit, passing through points (b) and (c).
The quantity of air returning to the unit is minimized by the high pressure loss in the mitered elbows. This
pressure loss plus the air flowing through the bypass connected at point (c)
ensures that the air entering the condensate drain pan, will not produce blowing and geysering
and an aerosol mist. At the
same time, the counter-flow of condensate and air creates a pulsing action
that ensures free passage of debris.
Hence, the potential for freeze-up
and flow blockage—a common problem with a condensate traps—is
nil. Moreover, since this drain seal
does not depend upon water to form a seal, it is not affected by condensate
evaporation and water leaks. Thus, the
blowing and geysering of condensate and the
accompanying operating costs plus the health problems—frequently caused by
dry traps—are eliminated. |
