Accurex XRV-25-5I Series Installation, Operation And Maintenance Manual

Also see for XRV-25: Installation, operation and maintenance manual

Accurex XRV-25-5I Series Installation, Operation And Maintenance Manual Manual pdf 16 page image

Packaged Rooftop Ventilator16Factory-Installed Refrigeration System ComponentsPackaged DX Cooling with Three Way Hot Gas Reheat and Hot Gas Bypass1. Compressor2. High Limit Pressure SwitchThe switch opens when refrigerant pressureincreases above the set point in the discharge line.A manual reset is then required.3. Hot Gas Reheat Valve (optional)Units equipped with a reheat coil use a three-way valve with actuator to control the supplyair discharge temperature of the unit duringdehumidification mode. The unit controller providesa 0-10 VDC signal to control the amount of reheatto meet the supply temperature set point4. Hot Gas Reheat Coil (Optional)5. Hot Gas Reheat Check Valve (Optional)6. Condenser Fans7. Condensing Coil8. Liquid Receiver (Optional)9. Liquid Line Filter Drier10. Sight Glass11. Fan Cycle Switch(es)The switch(es) open or close based on liquidrefrigerant pressure to control the condensing fansto maintain liquid pressure.12. Thermostatic Expansion Valve (TXV)Each unit is equipped with a TXV on eachrefrigerant circuit. The valve controls the flow ofliquid refrigerant entering the evaporator coil bymaintaining a constant, factory-set superheat of10°F. The valve is adjustable and is located on theside of the evaporator coil and can be accessedthrough the coil access panel.13. Evaporative Coil14. Low Limit Pressure SwitchThe switch is installed on the suction line anddisables the DX system when the suction pressuredrops below the set point. The switch will auto resetwhen the pressure rises above the auto-reset setpoint.15. Service Access Ports16. Hot Gas Bypass Manual Shut Off Valve (Optional)Used to disable hot gas bypass for service andtroubleshooting procedures.17. Hot Gas Bypass Valve (Optional)On units equipped with hot gas bypass, hot gasfrom the compressor is injected into the liquid lineof the evaporator coil after the TXV.Valve Adjustment - To adjust the valve, connecta pressure gauge to the suction line and block theentering air to the evaporator coil. The valve shouldbegin to open when the suction pressure drops toapproximately 115 PSIG for R-410A (the valve willfeel warm to the touch). Adjustments are made byfirst removing the cap on the bottom of the valveand then turning the adjusting stem clockwise toincrease the setting pressure (counterclockwiseto decrease). Allow several minutes betweenadjustments for the system to stabilize. Whenadjustment is complete, replace the cap on thevalve.18. Pressure Gauge & Transducer (Optional ECcondenser fans only)See Optional Electronically Commutated (EC)Condenser Fans under the component operation.