Stimmen - 4, Durchschnittliche Bewertung: 3.5 ( )

Hersteller: Lifebreath Dateigröße: 1.4 mb Dateiname: Unterrichtssprache:

When the outside air temperature drops below 23'F (-5°C), a defrost timer is activated which provides for an automatic defrost cycle every 17 minutes. During the automatic defrost cycle the fresh air supply is shut off for approximately 4.5 minutes while the exhaust fan continues to operate. This allows warm inside air to flow over the heat exchanger core melting any frost accumulation. After the defrost period, the fresh air supply fan automatically returns to the normal speed and fresh outside air continues to be drawn into the building. Water from the melted frost collects in the bottom drip pans and drains out through the bottom drain connections. The defrost cycle repeats automatically until the air temperature rises above 23*F (-5*C). The defrost control has a self-test feature which initiates the defrost cycle whenever the unit is started or there is a power interruption. The fan defrost operates in the defrost mode for the 4.5 minute cycle time and then returns to normal operation. The LED light indicating defrost on the control panel of the HRV * is on during this period. 2 DAMPER DEFROST The Models700DD, 900DD and 1200DD have an electronically controlled damper defrost mechanism. If the outside temperature drops below 23°F(-5°C), the defrost timer is activated. Afterwaiting approximately 17 minutes (during which time the core may experience some nominal frost build-up), the timer activates a motor driven damper door mechanism which opens the defrost port while at the same time closing off the supply air from outside. After approximately 4.5 minutes, the damper operates in the opposite direction to close off the defrost port and reopen the fresh air at the supply port. The 17 minute wait time and 4.5 minute defrost cycle repeat until the temperature again rises above 23°F (-5'C). The defrost mechanism incorporates an easy to "self-test " feature. Each time power to the unit is interrupted (unplugged then plugged back in gr turned OFF then ON, etc.), the unit initiates a defrost cycle. The defrost L.E.D. illuminates and the damper door operates for the pre-set 4.5 minute (approximate) time interval. This allows visual inspection of the operating components involved in the defrost cycle as they perform their function. LOCATION for MOUNTING The HRV must be located in a heated space where the surrounding air temperature does not fall below the freezing point. The exhaust air temperature must be above 60°F (16°C) for proper defrost operation. If the air temperature is too low the defrost time may need to be increased. The unit must be mounted level (horizontal) to obtain proper drainage of water from the heat exchange cores and drip pans.The warranty will be void if these conditions are not met. Typically, the HRV is positioned close to an outside wall or the roof to simplify the connections and keep the length of insulated ducting required for the fresh air intake to a minimum. The fresh air inlet may either be at the top for a roof inlet or at the end for a wall connection on a DD model (field modification). A minimum clearance of 36 in. (90 cm) in front of the HRV is recommended to service the heat exchanger cores and the filters. The four polyester reinforced PVC straps supplied are intended to be used to hang the HRV from floor or ceiling joists. The straps should be attached to the top end corners of the HRV case. Securely fasten the other end of the straps with large head screws or bolts. The straps are designed to reduce the possibility of any fan vibration being transmitted to the floor joists or alternately preventing any vibration in the floor from being transmitted to the ducting. The HRV may also be mounted on an equipment platform providing the drain hoses are clear and there is sufficient space to open the doors for servicing. Install the drain pans in the bottom of the HRV so the drain connections protrude through the holes provided. See Figure #1 for location of the drain pans and the drain connections. Inverting the T connection will form a trap in the drain. Use drain hoses with hose clamps to connect the drain pan outlets to a floor drain or standpipe. Make sure the drain line slopes down to the outlet and if this is not possible a condensate pump will be required for positive removal of the water. Protect the drain line from freezing. DEFROST AIR FROM INSIDE (DD MODELS) DAMPER ON DD MODELS \ FRESH AIR FROM OUTSIDE (DD MODELS) CORES FRESH AIR FROM OUTSIDE (FD MODELS) STALE AIR FROM INSIDE DRIP TRAY Figure 1 Front View Schematic of Typical HRV Model MOTORS STALE AIR TO OUTSIDE FRESH AIR TO INSIDE NUT AND WASHER FINGER TIGHTEN ONLY!! T-CONNECTION T 3 THE DUCTWORK SYSTEM A well designed ducting system will ...

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