Introduction
Radiant systems are gaining popularity due
to their ability to offer increased energy
efficiency and cost savings when compared
with traditional all-air systems. As more
experience is gained in designing radiant
systems, it is recognized that the control
systems and accessories associated with
these systems carry unique characteristics
and opportunities. For this reason, Price
controls for radiant systems have been
designed to be as versatile and modular
as possible, and accessories and options
have been chosen to compliment both the
controls and system.
Price Intelligent Controller for Radiant
Products (PIC-HP)
The PIC-HP is a standalone or networkable,
fully digital and programmable controller.
This control solution is ideal for managing
the sequences of Price radiant heating and
cooling products. The PIC-HP is an advanced
and configurable proportional integral
(PI) controller that allows for exceptional
user comfort and energy efficiency. It is
designed specifically to manage the control
requirements of radiant systems.
The PIC-HP is designed with a modular
architecture and includes BACnet
networking as standard. This gives the
customer flexibility by providing both the
“core” controller as well as powerful control
and communication options with the use of
the expansion modules.
Typical Application Overview
The PIC-HP can be factory configured to any
one of the eight standard control sequences,
as well as custom sequences, if required.
There are six standard sequences that
control water flow only, and two standard
sequences that control the water flow
and VAV air (variable air volume). The
standard control sequences are available
for either 2 pipe or 4 pipe operation and
indicate the control output used with the
associated actuator type (on/off or 0-10Vdc
modulating). Typical control sequences for
water and air include:
On/Off, 2 Pipe, Constant Air Volume
(Sequence #9701)
Chilled Water Supply Only
Upon an increase in room temperature
above the set-point, the air volume will
remain at its pre-selected level while the
cold radiant valve opens fully. When the
room temperature decreases to the setpoint,
the cold water actuator turns off the
flow.
On/Off, 2 Pipe, Constant Air Volume
(Sequence #9703)
Hot Water Supply Only
Upon a decrease in room temperature
below the room set-point, the air volume
will remain at its pre-selected level while the
hot radiant valve opens fully. When the room
temperature increases to the set-point, the
hot water actuator turns off the flow.
Modulating, 2 Pipe, Constant Air
Volume (Sequence #9700)
Chilled Water Supply Only
Upon an increase in room temperature
above the room set-point, the air volume
will remain at its pre-selected level while the
cold radiant valve modulates from closed to
open in proportion to the room temperature.
Upon a decrease in room temperature, the
cold radiant valve modulates closed.
Modulating, 2 Pipe, Constant Air
Volume (Sequence #9702)
Hot Water Supply Only
Upon a decrease in room temperature
below the room set-point, the air volume
will remain at its pre-selected level while the
hot radiant valve modulates from closed to
open in proportion to the room temperature.
Upon an increase in room temperature, the
hot radiant valve modulates closed.
On/Off, 4 Pipe, Constant Air Volume
(Sequence #9705)
Chilled Water Supply
Upon an increase in room temperature
above room the set-point, the air volume will
remain at its pre-selected level while the cold
radiant valve opens fully. When the room
temperature decreases to the set-point, the
cold water actuator turns off the flow. The
hot water valve remains fully closed.
Dead Band
With no demand in the space (ie. when the
temperature is at or close to the set-point),
the water valves (hot and cold) remain
closed and the air volume remains constant.
Hot Water Supply
Upon a decrease in room temperature
below the room set-point, the air volume will
remain at its pre-selected level while the hot
radiant valve opens fully. When the room
temperature increases to the set-point, the
hot water actuator turns off the flow. The
cold water valve remains fully closed.
Modulating, 4 Pipe, Constant Air
Volume (Sequence #9704)
Chilled Water Supply
Upon an increase in room temperature
above the room set-point, the air volume
will remain at its pre-selected level while the
cold radiant valve modulates from closed to
open in proportion to the room temperature.
Upon a decrease in room temperature, the
cold radiant valve modulates closed. The
hot radiant valve is always fully closed.
|
|
Dead Band
With no demand in the space (ie. when the
temperature is at or close to the set-point),
the water valves (hot and cold) remain
closed and the air volume remains constant.
Hot Water Supply
Upon a decrease in room temperature
below the room set-point, the air volume
will remain at its pre-selected level while the
hot radiant valve modulates from closed to
open in proportion to the room temperature.
Upon an increase in room temperature, the
hot radiant valve modulates closed. The cold
radiant valve is fully closed.
Note: Dynamic Heat-Cool Changeover
for 2 Pipe Systems (HCCO)
|
The controller will modulate the water valve
when heating or cooling is required.
For example, if the space set-point is 72°F
and the water temperature is below the
set-point, the system is in cooling mode.
If the space set-point is 72°F and the water
temperature is above the set-point, the
system is in heating mode.
PIC-HP HCCO sequences are available for
2 pipe configurations, where both cold
and hot water are supplied. The supplied
changeover probe (PIC-PRB) allows HCCO
operation. If no probe is connected to the
thermostat, the controller assumes that it
is receiving chilled water supply and acts
accordingly.
Modulating, 2 Pipe, Variable Air
Volume (Sequence #9706)
Chilled Water Supply Only Upon an increase in room temperature
above the room set-point, the air volume
will remain at minimum ventilation to meet
building code and latent load requirements
while the cold radiant valve modulates from
closed to open in proportion to the room
temperature. The air volume will modulate
from minimum position to full open as a
secondary stage of cooling in proportion
to the room temperature, when required.
Upon a decrease in room temperature or
during off-peak hours, the cold radiant
valve modulates closed and the air volume
is modulated to minimum ventilation.
Modulating, 4 Pipe, Variable Air
Volume (Sequence #9707)
Chilled Water Supply
Upon an increase in room temperature
above the room set-point, the air volume
will remain at minimum ventilation to meet
building code and latent load requirements
while the cold radiant valve modulates from
closed to open in proportion to the room
temperature. The air volume will modulate
from minimum position to full open as a
secondary stage of cooling in proportion
to the room temperature, when required.
Upon a decrease in room temperature or
during off-peak hours, the cold radiant
valve modulates closed and the air volume
is modulated to minimum ventilation. The
hot radiant valve is always fully closed.
Dead Band
With no demand in the space (ie. when
the temperature is at or close to the setpoint),
the water valves (hot and cold)
remain closed and the air volume remains
at minimum ventilation.
Hot Water Supply
Upon a decrease in room temperature
below the room set-point, the air volume
will remain at minimum ventilation to meet
building code while the hot radiant valve
modulates from closed to open in proportion
to the room temperature. The air volume
will modulate from minimum position to full open as a secondary stage of heating
in proportion to the room temperature,
when required. Upon an increase in room
temperature or during off-peak hours, the
hot radiant valve modulates closed and
the air volume is modulated to minimum
ventilation. The cold radiant valve is always
fully closed.
|