CEMP-E
TI 811-12
18 August 1998
(2) Occupied Mode. The UMCS will modulate the secondary heating control valve when the
secondary zone pump is operating) to maintain the heating zone occupied space temperature setpoint.
(3) Unoccupied Mode. The UMCS will modulate the secondary heating control valve (when the
secondary zone pump is operating) to maintaining the heating zone unoccupied space temperature.
b. Hot Water Boiler and Primary/Secondary Heating System Sequence of Operation Figure 8-2 and
(1) All Modes. The UMCS will start and stop the primary and secondary pumps in sequence
based on the signal from an outside-air temperature sensor as shown. The UMCS will enable local
control of the hot water boiler when the primary pump is operating. The UMCS will control the primary
loop hot water supply temperature by modulating the hot water boiler bypass valve in response to a
temperature sensor located in the hot water supply line to maintain its setpoint. The UMCS will reset the
hot water supply temperature setpoint with respect to outside air temperature in a linear schedule as
shown. Reduced-flow control of the hot water bypass valve will be coordinated with the boiler
manufacturer's recommendations and boiler safety settings. The UMCS will disable boiler operation
when the primary pump is off.
(2) Occupied Mode. The UMCS will modulate the secondary heating control valve (when the
secondary zone pump is operating) to maintain the heating zone occupied space temperature setpoint.
(3) Unoccupied Mode. The UMCS will modulate the secondary heating control valve (when the
secondary zone pump is operating) to maintaining the heating zone unoccupied space temperature.
c. Hot Water Boiler with Constant Volume Circulating Loop and Primary/Secondary Heating System
Sequence of Operation (Figure 8-3 and Table 8-3).
(1) All Modes. The UMCS will start and stop the primary and secondary pumps in sequence
based on the signal from an outside-air temperature sensor as shown. The UMCS will enable local
control of the hot water boiler and boiler circulating pump when the primary pump is operating. The
UMCS will control the primary loop hot water supply temperature by modulating the hot water boiler
bypass valve in response to a temperature sensor located in the hot water supply line to maintain its
setpoint. The UMCS will reset the hot water supply temperature setpoint with respect to outside air
temperature in a linear schedule as shown. Reduced-flow control of the hot water bypass valve will be
coordinated with the boiler manufacturer's recommendations and boiler safety settings. The UMCS will
disable boiler operation when the primary pump is off. The boiler circulating pump will remain in
operation for a preset adjustable time period after the boiler is disabled.
(2) Occupied Mode. The UMCS will modulate the secondary heating control valve when the
secondary zone pump is operating) to maintain the heating zone occupied space temperature setpoint.
(3) Unoccupied Mode. The UMCS will modulate the secondary heating control valve when the
secondary zone pump is operating) to maintain the heating zone unoccupied space temperature.
d. High-Temperature Hot Water/Hot Water Converter and Primary/Secondary Heating System
Sequence of Operation (Figure 8-4 and Table 8-4).
(1) All Modes. The UMCS will start and stop the primary and secondary pumps in sequence
based on the signal from an outside-air temperature sensor as shown. The UMCS will enable control of
the high temperature hot water/hot water converter control valve when the primary pump is operating.
The UMCS will control the primary loop hot water supply temperature by modulating the high temperature
hot water control valve in response to a temperature sensor located in the hot water supply line to
maintain its setpoint. The UMCS will reset the hot water supply temperature setpoint with respect to the
outside air temperature in a linear schedule as shown.
8-2
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