3003 W CASINO RD BLDG 40-41 2018-09-21

T f ��`�� r��d' � . . . . The economizer reduces the cost of air conditioning by using outside air when acceptable to cool the room. The factory installed Marvair'� econamizer has integral pressure relief. On a signal from a thermostat that cooiing is required, either mechanical cooiing with the compressor or free caoling with the economizer is provided. The Marvair economizer is capable of bringing in outside air equai ta 100% of the rated coofing capacity of the unit and has built in pressure relief. An internal enthalpy contraller determines whether the outside air is sufficiently cool and dry to be used with cooling. If suitable, the campressor is locked out and the economizer damper opens to bring in outside air. The temperature at which the economizer opens is adjustable from approximately 55°F (13°C} to 73°F (23°C} at 54% RH. If the outside air becomes too hot or humid, the economizer damper closes completely or to a minimum position and mechanical cooling is activated. When used with minimum position potentiometer (optional), the Marvair� economizer can meet requirements of ASHRAE Std. 62. ��"�� '�� a . .�� The Marvair GreenCube� ERV is an enthalpy plate heat exchanger that transfers both sensible and latent energies between outgoing and incoming air streams in a cross flow arrangement. Except for two air movers, it has no moving parts. It can introduce up to a maximum of 300 cfm of outside air into the cfassroom. Two MERV 6 type filters are used on both sides of the enthalpy core. The fresh air and exhaust motors have indspendent speed controllers to permit each of the motors to be reguiated independently. The media is impregnated with a RC134 polymeric desiccant that exchanges water by direct vapor transfer using mafecular transport without the need af candensation. The GreenCube° ERV will operate at temperatures as low as 10°F with no defrost mechanism. In addition, the desiccant is a bactericide. The'GreenCube° ERV isonly avaiiable on HVPSA units {2-stage carnpressor}. All HVPSA units wi#h the GreenCube� ERV, inciuding the HVPSA35 and HVPSA42, are in t�e F�VPSA49/60 cabinet (see page 28). �� Marvair-�a heat pumps equipped with Hot Gas Reheat (HGR) alfow the indaor humidity of the controlled environment to be maintained at or below a certain humidity set point. These units do not have the ability to add humidity to the classroom. Dehumidification is achieved by aperating mechanical cooling in conjunction with a hot gas reheat coil. Operatian - If the humidity rises above the set point on the humidity controller and th.e temperature in the classroom is satisfied, both mechanical cooling and the HGR coil operate to temper the air and lower the humidity. If the temperature in the classroom rises above (or falls below} the set point of the thermostat and the unit is operating in the dehumidification mode, the call for coofing (or heating) will override the call for dehumidification and the coil is disengaged until the thermostat is satisfied. This assures the environment temperature is maintained as first priority and humidity control is second. �� Each Classic heat pump has a PC baard that contrals the operatian of the indoar blower, the compressor and the reversing valve while providing high refrigerant pressure and loss of refrigerant pratection with an integral defrost funetion. In addition, tiie board has user selectab[e pins and patentiometers for multi-function control. Ffigh&loss of refrigerant protection— If either of these fault conditions occur twice within an one hour, the control baard will enter into and indicate the lockout mode. In the lockout mode, the compressor will not operate, the alarm output is energized and the red LED will blink to indicate which fault has occurred. The user can select either Normally Open or Normally Closed contacts. Compressor anti-short cycle protection — An integral three minute delay prevents compressor from destructive short cycling. Loss of Refrigerant By-pass Timer — To prevent nuisance fault alarms, the board ignores a loss of charge fault for three minutes on start-up of the compressor. Defrost Control —The defrost cycle removes ice build-up an the outdoor coil during the heating cycle. If the defrost sensar senses a coil temperature of 32°F while in the heat mode, a 30, 60 or 90 minute (user selectable) delay period will begin. After the delay period if the sensor is still ca►ling far a defrost cycle, the outdoor fan will be stopped and the reversing valve energized. The defrost cycle will stop if the defrost sensor registers a temperature of 50°F or after 10 minutes. ' Classic AVPA2�-3�36-42-46-60,HVPA24-30-30-42-49-60&HVPSA36-42-44-00 PDS 1(1/2015 rev.6 4 �