Daikin RDT Installation And Maintenance Manual

Also see for RPS: Installation and maintenance manual Installation and maintenance manual Installation manual Manual

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Daikin RDT Installation And Maintenance Manual Manual pdf 37 page image

M eChanICal InsTallaTIonwww.DaikinApplied.com 37 IM 893-10 • ROOFPAK SINGLEZONE UNITSSteam Coil Freeze ConditionsIf the air entering the steam coil is below 35°F (2°C), note thefollowing recommendations:1. Supply 5 psi (34.5 kPa) steam to coils at all times.2. Modulating valves are not recommended. Control shouldbe by means of face and bypass dampers.3. As additional protection against freeze-up, install thetap sufficiently far below the coil to provide an adequatehydrostatic head to ensure removal of condensate duringan interruption on the steam pressure. Estimate 3 ft. (914mm) for each 1 psi (7 kPa) of trap differential required.4. If the unit is to be operated in environments withpossible freezing temperatures, an optional freezestat isrecommended. See Freeze Protection on page 79 foradditional information.Figure 40: Steam Valve PackageDamper AssembliesThe optional damper assemblies described in this sectionnormally are ordered with factory-installed actuators andlinkages. The following sections describe operation and linkageadjustment of the factory-installed option.Economizer DampersOutside air intake is provided on both sides of the unit, and thereturn air path is at the center of the damper set. As the singleactuator modulates the outside air dampers open, the returnair dampers close. Exhaust air exits the unit through the gravityrelief dampers provided at the end of the economizer section.The damper is set so that the crankarm moves through a90- degree angle to bring the economizer dampers from fullopen to full close (see Figure 41). Access to the actuator andlinkage is from the filler section. Mechanical stops are placed inthe crankarm mounting bracket. Do not remove stops. Drivingthe crankarm past the stops results in damage to the linkageor damper. The unit ships with a shipping bolt securing thelinkage crankarm. Remove shipping bolt before use.NOTE: For good airflow control, adjust linkages so damperblades do not open beyond 70 degrees. Opening adamper blade beyond 70 degrees has little effect onits airflow.Do not “overclose” low leak damper blades. The edgeseal should just lightly contact the adjoining blade.The blades will lock up if they are closed so far theseal goes over center.Figure 41: Damper AdjustmentAirflow