c) Verify space type sensors by placing the test
instrument as close as possible to the sensor to measure
identical conditions. Maintain the test for a sufficient length
to ensure achieving stable conditions.
a) Each controller shall be configured for its
specified service. Verify each sequence of operation for each
HVAC system and subsystem. Verify that each controlled device
responds to the proper controller, in the proper manner, and at
the proper time. Verify the fail-safe position for each
component of the system.
b) Set the time schedule of controllers in accordance
with the sequence of operation and the established time schedule.
System Dynamic Checkout. Perform weather-dependent
test procedures that cannot be performed by simulation in the
appropriate climatic season. When simulation is used, verify the
actual results in the appropriate season.
a) Use the controllers' manual-automatic switches as
the means of manipulating control devices such as dampers and
valves to check operation and to effect stable conditions, prior
to making measurement checks.
b) Perform a controller tuning procedure, which shall
consist of setting the initial proportional, integral, and
derivative (PID) mode constants, controller setpoints, and
logging the settings. Tuning shall be self-tuning operation by
the controller unless manual tuning is necessary.
Controller Manual-Tuning Procedure. A controller
manual tuning procedure is described in three steps using a
constant temperature setpoint controller as an example.
This step shall consist of the following:
(1) Index the controller manual-automatic switch
to the automatic position, and set the integral and derivative
mode constants to zero.
(2) Set the proportional mode constant to an
initial setting of 8 percent. This corresponds to a 2.0 ma per
degree F or a 1.5 psig per degree F proportional controller
output change for a 100-degree F span. This causes the
controller output signal to vary from zero output to full output
for an input signal change representing an 8-degree F change.