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Drive Motor
The enthalpy wheel comes standard with a variable speed drive motor, which is pre-wired to turn in the
proper direction. The motor can adjust speed to lower the enthalpy’s wheel capacity during frosting
conditions. This lowered capacity allows the wheel to recover energy still while preventing frosting. During
non-frosting conditions, the modulation of the wheel allows enhanced capacity control of wheel for greater
turn-down and more precise discharge control.
Frost Protection (Optional)
illustrates frost prevention conditions. During extremely cold winter conditions, the wheel can
frost overdue to the moisture content of the return/exhaust air. A frozen wheel will increase static pressure
and reduce efficiency of the wheel. If the wheel fully freezes, the host unit can be starved of supply air. To
avoid this situation, the recovery wheel comes standard with a variable speed motor that modulates down
during frosting conditions.
Figure 44 - Frost Prevention Psychrometric Chart
Variable Speed Frost Prevention
When there is a threat of frost on the enthalpy wheel, the wheel is slowed down so that less enthalpy
transfer occurs, and frosting of the wheel is avoided. Frosting can occur on the enthalpy wheel when the
exhaust air leaving the wheel is saturated. This condition occurs when the energy transfer and saturated
air lines intersect on a psychrometric chart, and it does not occur when these two lines do not intersect.
Energy Recovery Exhaust Hoods
Units with the optional energy recovery module have an exhaust hood. Each hood is factory installed over
the barometric relief, allowing the unit to function in adverse weather without the risk of water/debris
infiltration.
Exhaust Fan
Unit utilizes an integral ECM exhaust fan that features various control modes to optimize energy transfer
and ensure proper air movement. Exhaust cabinet features barometric relief that seals when the exhaust
fan is not powered. This will allow for return air to be utilized when the ERV is off.
Slide-Out Wheel
The wheel can be pulled out to facilitate cleaning and servicing. Power wires for the wheel will need to be
unfastened from the lid of the module to allow the full range of motion necessary to service the wheel.
Dry Bulb
Humidity
Ratio
Saturated
Air
Saturated
Air
Saturated
Temperature
Frost
Conditions
No Frost
Conditions