Catalogue

UNT-PRC001-EN 77
Mechanical Specifications
Piping packages are available in either basic or deluxe configurations. The deluxe package includes
unions at the coil connections and a 20-mesh strainer on the supply side with a pressure rating on
the strainer of up to 400 psig. The basic package does not include either unions or the strainer. A
choice of end valves are available on both the basic and deluxe piping packages.
The piping package is designed so that any condensation is directed into the UniTrane auxiliary
drain pan. Insulation of piping package is not required.
Ball Valve Supply and Return
A ball-type stop valve is available on both the supply and return of the piping package. The ball
valve is a shutoff valve only with a maximum working pressure of 400 psig.
Ball Valve Supply, Manual Circuit Setter Return
A ball valve is provided on the supply with a manual circuit setter on the return. The manual circuit
setter is a combination flow-setting device and shutoff valve that includes two Schrader ports. The
maximum working pressure of the valve is 300 psig.
Ball Valve S & R, Auto Circuit Setter Return
Ball type end valves are mounted on the supply and return, with an additional auto circuit setter
mounted on the return. The auto circuit setter is an automatic flow control valve that is sized to
allow a specific flowrate through the coil. Auto circuit setters also include two P/T plugs and have
a maximum working pressure of 400 psig.
Control Valves
Two-Way, Two-Position Control Valves
Two-way, two-position valves are rated for a maximum pressure differential across the valves of
30 psig. The valves are also available with a close-off pressure of 50 psig. The valve actuator is
easily removable for service without removing the valve body from piping. Use some means, such
as a pump and chiller bypass, to ensure the maximum closed off ΔP rating of the two-way valves
is not exceeded.
Three-Way, Two-Position Control Valves
Normally open three-way, two-position valves are rated for a maximum 28 psig pressure
differential across the valves. Normally closed three-way two-position valves are rated for a
maximum pressure differential across the valves of 20 psig. A bypass line is piped on all three-way
piping packages with a balance fitting to set flow through the bypass line. The balance fitting has
a maximum working pressure of 150 psig. The valves are also available with a maximum close-off
pressure of 50 psig. The valve actuator is easily removable for service without removing the valve
body from piping.
Modulating Control Valves
Two-way and three-way modulating valves are rated for a maximum pressure differential across
the valves of 50 psig (345 kPa). The modulating valves are available in Cv values of 0.7, 1.5, 2.5 and
4.0.
All two-position and modulating control valves have a maximum working pressure of 300 psig.
The maximum entering water temperature of the valve is 200°F.
Electric Heat Coil
The auxiliary electric heating coil is provided as either the total source of heat or auxiliary
intermediate season heating. The electric heat coils are located in the preheat position, and are the
open-wire type. The coils are a nickel chromium element design. The electric heat operates at the
same voltage as the unit, and only a single power connection is necessary.
All units with factory-mounted electric heat are UL-listed and interlocked with the fan motor switch.
A call for electric heat operation will turn the fan on. Motors controls are synchronized with
Options
UNT-PRC001-EN.book Page 77 Tuesday, May 8, 2012 10:54 AM