MIL-HDBK-1003/3
a) Keep the input and output points to the minimum
number required for HVAC control and efficient building
operation. Follow the recommended point guidance provided in
par. 8.2. Follow the principle to "Keep it Simple."
b) Use standard control sequences for similar HVAC
control system applications.
c)
Show the following on control drawings as a
minimum:
(1) Flow diagram schematic of each mechanical
system showing sensors, equipment, and operators.
(2) Individual point list description for each
mechanical system.
(3) Electrical ladder diagram for each electrical
circuit controlled.
(4) Operating parameters - controller setpoints
and time schedules.
(5)
Detailed sequence of operation.
d) Use direct connection of temperature sensors when
possible. Use only precision thermistors (10,000 ohms) for room
sensing and 1000 ohm platinum RTDs for HVAC unit sensing.
e) Use room zone temperature sensors with pushbutton
override and setpoint adjustment integral to the sensor.
f) Do not modify the chiller microprocessor system
supplied with the equipment. Control and safety functions should
be the chiller manufacturer's responsibility. The DDC system
should only enable or disable the chiller, chilled water pump,
condenser water pump, and in some cases chilled water and
condenser water reset. For chillers 150 tons and larger, provide
an RS-485 communication between the chiller microprocessor and
the DDC system.
g) Do not modify the boiler microprocessor system
supplied with the equipment. Control and safety functions should
be the boiler manufacturer's responsibility. Design hot water
systems to maintain the boiler manufacturer's minimum temperature
when in operation but vary the hot water supply temperature as
required to meet the building's requirements.
106
Previous Page
