A SH / S-TRAC MANUAL
18 of 29 Feb 06
Sequence of Operation
When terminal H is powered and the time clock (or external enable) contact closes and powers terminal
HS, the S-TRAC will close the drain valve and enable the fill solenoid to commence filling the tank with
water. When the water level has reached the low level sensor/switch the gas fired burner is enabled if a
call for humidity is present. The fill valve will stay energized until the water level reaches the high level
sensor/switch. The burner will bring the water to boiling then modulate the firing rate to control the steam
output to maintain the required relative humidity.
The steam is then piped to the Engineered Air SORB distribution grid mounted in the air-stream. The
amount of steam produced will decrease as the burner firing rate lowers from a reduced call for humidity.
Water level will be automatically maintained between the low and high level probes. If the call for humidity
is satisfied and the burner is operating at low fire, it will shut down and wait. Steam output may be reduced
as the tank during re-fill.
When the time clock (or external enable) contact opens, or the internal run time monitor expires, the
S-TRAC will initiate the dump cycle. The burner is disabled and the drain valve opens. A sensor located in
the drain line constantly monitors drain temperature. If the drain temperature exceeds 120°F (49°C) the
mixing solenoid is enabled to add cool water to the drain. If the drain temperature reaches 140°F (60°C)
the drain valve will be disabled and begin to close to restrict the amount of hot water leaving the humidifier,
increasing the percentage of cool mixing water going to the drain.
Burner Control
The S-TRAC will directly control burner operation on the small sizes of SH humidifiers (SH-35,60,90).
These use hot surface ignition, constant combustion air, with 3:1 turndown. The burner and ignition control
are directly signalled from the S-TRAC. Refer to the burner set-up section of this manual.
The S-TRAC controller on large sizes of SH humidifiers (SH-120,240,400,650) interface to an Engineered
Air DJM high turndown burner controller. These style of 15:1 turndown burners have spark to pilot ignition
and modulating combustion air. Refer to the DJM manual included with the SH humidifier for burner
information and set-up procedures.
SPECIFIC CONTROL FUNCTION EXPLANATIONS
Probe safety checks
The S-TRAC constantly monitors the activity of the 2 level sensors/switches. If any discrepancies in the
sequence of level sensing occur, the S-TRAC will lockout on probe problem. For example, if the high level
sensor/switch makes before the low level sensor/switch.
Manymanuals.com
Manymanuals.de
Manymanuals.fr
Manymanuals.it
Manymanuals.pl
Manymanuals.cz
Manymanuals.es
Manymanuals-pt.com
Comentarios a estos manuales