Slant/Fin Caravan LDWO-1100-3-6 Application Manual page 16

SCG-400-S-4 CARAVAN CONTROL SYSTEM WIRING DIAGRAM
• Up to 4 space heating modules
POWER SUPPLY, PROVIDE DISCONNECT MEANS
1
AND OVERLOAD PROTECTION AS REQUIRED.
SEE FIGURE C1 FOR WIRING TO MODULE X X
2
CONNECTIONS.
SET SYSTEM ENABLE THERMOSTAT (T675A) AT
4
THE TEMPERATURE THAT THE BUILDING WILL
BEGIN TO REQUIRE HEAT (NORMALLY BETWEEN
40° F AND 60° F). MOUNT OUTDOOR SENSING
BULB ON NORTH (SHADED) WALL IN SUNSHIELD
#34886A.
LOW WATER CUTOFFS MUST BE INSTALLED AT A
6
LOCATION HIGHER THAN THE TOP OF THE
BOILERS.
ON SYSTEMS WITH MULTIPLE LOW WATER CUT-
7
OFFS AND/OR MANUAL RESET HIGH LIMITS,
REFER TO FIGURES C2 AND C3 PAGE 29 FOR
PROPER WIRING.
ON SYSTEMS WITH ONE LOW WATER CUTOFF,
INSTALL A JUMPER BETWEEN TERMINALS 1 AND 3
ON THE LOW WATER CUTOFF.
SEQUENCE OF OPERATIONS - SCG400
Space heating only
When outdoor temperature falls below the setting of the system
enable temperature control (T675A), the system is activated. The
outdoor reset control (T475A) will energize module #1 and regulate
the supply water temperature. As the outdoor temperature continues
T675A SETTING
Determine the proper setting of
each T675A thermostat by calculating
the percentage of the total heating load
that each T675A will energize and
apportion this over the operating
temperature range (enable temperature
minus design outdoor temperature).
to drop below the settings of the individual module temperature
controls (T675A), more stages are energized. The energized
modules are cycled as a group by the outdoor reset control (T475A).
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