24
ULTRA-SORB MODEL XV INSTALLATION, OPERATION, AND MAINTENANCE MANUAL
Sequence of operation
OPERATION
FULL-TIME HEAT EXCHANGER OPERATION WITH ELECTRIC OR PNEUMATIC
TEMPERATURE SWITCH
With control options #2 and #3, a 2-position (On-Off) shutoff control valve
is not used (see Figure 4-2). The Ultra-sorb XV internal heat exchanger
operates any time pressurized steam is available to the dispersion panel. Install
the temperature switch downstream of the internal heat exchanger to prevent
operation of the modulating control valve if steam is not fl owing through the
heat exchanger.
1. Upon air handling unit startup (Occupied Mode), air flow switch enables
modulating control valve. Start/stop of fan provided by BAS or other
control command.
a. If air fl ow interlock is provided by BAS, then the BAS must provide a
contact closure in series with the modulating valve 24 VAC power circuit
as shown on the wiring diagram shipped with the Ultra-sorb panel.
2. Humidification demand is provided by a 2-10VDC/4-20mA signal from
BAS/control signal or humidistat, to the modulating control valve.
3. Internal heat exchanger operates continuously. A temperature switch
(electric or pneumatic) senses condensate temperature leaving the heat
exchanger. If the temperature at the outlet of the heat exchanger falls
below 210°F (99°C), the temperature switch closes the modulating control
valve to prevent condensate buildup in the steam dispersion panel header.
