Specifications - Lord and Son Construction, Inc.

systems served by this system are not enabled, this system shall
not be enabled.
(2) When this system is enabled (SYS-ENA) the Pressure Control loop
shall be enabled.
b. HAND-OFF-AUTO Switch: The hot water pump variable frequency drive (VFD)
unit shall have an integral H-O-A switch:
(1) HAND: With the H-O-A switch in HAND position, the pump shall
start and run continuously. Pump speed shall be under manualoperator
control.
(2) OFF: With the H-O-A switch in OFF position, the pump shall stop.
(3) AUTO: With the H-O-A switch in AUTO position, the pump shall run
subject to the Hot Water Pump Start/Stop (HW-PMP-SS) command and
pump speed shall be under control of the DDC system.
c. roofs and Safeties
(1) DDC Hardware shall monitor all proofs and safeties.
(2) Proofs: None
(3) Safeties: None
(4) DDC Hardware reset of all proofs and safeties shall be via a
local binary push-button (RST-BUT) input to the DDC Hardware, via a
remote command to the DDC Hardware via SNVT or both (where the
Contractor provides both reset functions and the operator can use
either one to perform the reset), as shown on the Points Schedule
drawing.
d. Pressure Control: When this loop is enabled the DDC Hardware shall
modulate the pump variable frequency drive unit to maintain the pipe
system pressure at setpoint as shown, as measured by the differential
pressure tap and sensor as shown. When this loop is disabled, the DDC
Hardware capacity modulation output to the VFD shall be zero percent.
3.5 CONTROLLER TUNING
The Contractor shall tune each controller in a manner consistent with that
described in the ASHRAE FUN IP. Tuning shall consist of adjustment of the
proportional, integral, and where applicable, the derivative (PID) settings
to provide stable closed-loop control. Each loop shall be tuned while the
system or plant is operating at a high gain (worst case) condition, where
high gain can generally be defined as a low-flow or low-load condition.
Upon final adjustment of the PID settings, in response to a change in
controller setpoint, the controlled variable shall settle out at the new
setpoint with no more than two (2) oscillations above and below setpoint.
Upon settling out at the new setpoint the controller output shall be steady.
With the exception of naturally slow processes such as zone temperature
control, the controller shall settle out at the new setpoint within five (5)
minutes. The Contractor shall return the controller to its original
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