AAON Auto-Zone 2 GPC-XP User guide

WSHP Loop Control
Using The
GPC-XP Controller
Application Guide
www.az2controls.com

Table of Contents
WattMaster Controls, Inc.
8500 NW River Park Drive, Parkville, MO 64152
Toll Free Phone: [phone]
PH: [phone] · FAX: [phone]
E-mail: [e-mail]
GPC-XP Controller............................................................................................................................................ 3
Overview ......................................................................................................................................................................................3
Features .......................................................................................................................................................................................3
Water Source Heat Pump System Operation .................................................................................................. 4
Water Source Heat Pump Unit .....................................................................................................................................................4
Water Source Heat Pump System ...............................................................................................................................................5
Operation Of The WSHP Loop Controller ........................................................................................................ 6
Overview ......................................................................................................................................................................................6
Typical Sequence .........................................................................................................................................................................6
Pump On/Off -Control...................................................................................................................................................................6
Pump VFD Control .......................................................................................................................................................................6
WSHP Unit Compressor Enable ..................................................................................................................................................7
Heat Rejection..............................................................................................................................................................................7
Heat Addition................................................................................................................................................................................7
Emergency Shutdown ..................................................................................................................................................................7
Controller, Sensors & Related Hardware........................................................................................................ 8
Optional Communication Devices and Software ............................................................................................ 9
Communication, Baud Rate Settings & Wiring Info...................................................................................... 10
System Settings .........................................................................................................................................................................10
Important Wiring Considerations................................................................................................................................................10
Environmental Requirements.....................................................................................................................................................10
Mounting.....................................................................................................................................................................................10
Power Supply .............................................................................................................................................................................10
Communication, Baud Rate Settings & Wiring Info...................................................................................... 11
Input Wiring.................................................................................................................................................... 12
Output Wiring ................................................................................................................................................. 13
Conguring The Controller ............................................................................................................................ 14
General .....................................................................................................................................................................................14
Status Screen ...........................................................................................................................................................................14
Analog Input #1 ..........................................................................................................................................................................15
Analog Input #2 ..........................................................................................................................................................................17
Analog Input #3 ..........................................................................................................................................................................17
Analog Input #4 ..........................................................................................................................................................................17
Analog Input #5 ..........................................................................................................................................................................19
Analog Input #6 ..........................................................................................................................................................................19
Analog Input #7 ..........................................................................................................................................................................19
Analog Input #8 ..........................................................................................................................................................................19
Binary Input #1 ...........................................................................................................................................................................21
Binary Input #2 ...........................................................................................................................................................................21
Binary Input #3 ...........................................................................................................................................................................21
Binary Input #4 ...........................................................................................................................................................................23
Binary Input #5 ...........................................................................................................................................................................23
Binary Input #6 ...........................................................................................................................................................................23
Binary Input #7 ...........................................................................................................................................................................25
Binary Input #8 ...........................................................................................................................................................................25
Relay Output #1 .........................................................................................................................................................................25
Relay Output #2 .........................................................................................................................................................................27
Relay Output #3 .........................................................................................................................................................................27
Relay Output #4 .........................................................................................................................................................................29
Relay Output #5 .........................................................................................................................................................................29
Relay Output #6 .........................................................................................................................................................................31
Relay Output #7 .........................................................................................................................................................................31
Relay Output #8 .........................................................................................................................................................................33
Analog Output #1 .......................................................................................................................................................................33
Analog Output #2 .......................................................................................................................................................................35
Analog Output #3 .......................................................................................................................................................................35
Analog Output #4 .......................................................................................................................................................................36
Visit our web site at www.az2controls.com
Form: AZ2-WSLC-AGD-01B Copyright 2017 WattMaster Controls, Inc.
WattMaster Controls, Inc. assumes no responsibility for errors or omissions.
This document is subject to change without notice.
Table Of Contents
2WSHP Loop Controller GPC-XP Guide

Overview
General
The GPC-XP is a software driven, multi-function controller which can
be congured to a variety of applications from simple on/off time clock
control to more complex sequences involving multiple input and outputs
control based on basic logic functions.
The purpose of this guide is to illustrate the GPC-XP capability for Water
Source Heat Pump Central Plant control applications.
GPC-XP Used As A WSHP Loop Controller
The GPC-XP Controller can be congured to control the central water
loop for individual water source heat pumps installed in a typical water
source heat pump system. See Figure 2 for a general layout of a typical
Water Source Heat Pump system.
The GPC-XP can operate stand-alone or be used with the Auto-Zone
2 (AZ 2) Control System to utilize the transfer of commonly shared
information such as outside air temperature and proof of water ow
over a communication network.
The main purpose of the GPC-XP controller, when used as a Water
Source Heat Pump Loop Controller, is to provide water ow in the sys-
tem when needed. It also maintains the proper loop water temperature
required at any given time by monitoring either the Loop Return Water
Temperature or the Loop Supply Water Temperature. The settings should
typically be congured to supply between approximately 60° F to 90° F
water temperatures to the installed water source heat pumps. Generally
any loop water temperature below 60° F would require heat addition
(hot water boiler) and any loop water temperature above 90° F would
require heat rejection (closed circuit cooling tower).
When a higher water temperature is required, (water is below the de-
sign loop water temperature) the cooling bypass valve is energized and
bypasses the cooling tower and the heat addition (hot water boiler) is
enabled by the controller to heat the water to the required temperature.
The heat addition setpoints are fully adjustable and can be set according
to your systems requirements.
When a lower water temperature is required in the loop, (water is
above the design loop water temperature) the cooling bypass valve is
de-energized and the cooling tower is enabled by the controller to bring
on a cooling tower fan and tower spray pump to cool the water to the
required temperature. The heat rejection setpoints are fully adjustable
and can be set according to your systems requirements.
The AZ 2 Unit Controller can be congured to control individual water
source heat pumps. The AZ 2 Controller will work in conjunction with
the GPC-XP Loop Controller to send and receive data critical to an ef-
cient WSHP system.
For additional information about the Auto-Zone 2 control system, please
visit our web site at www.az2controls.com for complete information
and resources.
GPC-XP Controller
Features
Controller
• Stand-alone or network operation.
• Onboard time clock
• Built in USB port for direct connection to computer
• Status indicators for:
• Power
• Communications
• Binary inputs
• Relay outputs
• Congurable controller provides exibility for variations in
the application.
Software
• Purpose built Prism front end graphical software eliminates
programing. Simple conguration through point & click
selection and drop down menus
• Prism software is free to download from AZ 2 web site
Conguration and Setpoints for:
• Outside air low limit
• Pump control:
• On/Off based on time schedule or demand call
• Variable ow pump control based on differential
pressure
• Proof of ow
• Minimum runtime timers
• Automatic lead/lag changeover to equalize pump
usage
• Automatic pump failure changeover
• Runtime counters
• Boiler control:
• Adjustable setpoints
• Boiler enable
• Automatic loop temperature control
• Bypass valve control
• Proof of run
• Boiler fail alarm
• Emergency shutdown
• Cooling Tower:
• Adjustable setpoints
• Tower Fan – on/off and VFD
• Spray pump
• Spray pump proof of ow
• Sump heater control
• Monitor sump water temp
• Built in USB port for direct connection to computer
Introduction
3
WSHP Loop Controller GPC-XP Guide

Water Source Heat Pump System Operation
Figure 1: Typical Water Source Heat Pump Unit Operation Diagram
Water Source Heat Pump Unit
A water source heat pump is a self-contained water-cooled packaged
heating and cooling unit with a reversible refrigerant cycle. Its compo-
nents are typically enclosed in a common casing, and include a tube-
in-tube heat exchanger, a heating/cooling coil, a compressor, a fan, a
reversing valve and controls.
During the cooling mode, the tube-in-tube heat exchanger functions
as a condenser and the coil as an evaporator. In heating mode, the
tube-in-tube heat exchanger functions as an evaporator and the coil
as a condenser. A reversing valve is installed in the refrigerant circuit
permitting changeover from heating to cooling, and vice versa. The
condenser and evaporator tubes are designed to accept hot and cold
refrigerant liquid or gas.
General Information
4WSHP Loop Controller GPC-XP Guide

Water Source Heat Pump System Operation
Figure 2: Typical Water Source Heat Pump System Diagram
Water Source Heat Pump System
The water source heat pump system is, by denition, a heat recovery
system. It is best applied to buildings that have simultaneous cooling
and heating loads. This is the case during winter months when the
interior zones of a typical building require cooling while the exterior
zones require heating. When a water source heat pump system is used,
the heat rejected by the cooling units is used to warm the zones calling
for heat. A water heater or boiler is generally used for adding heat to the
condensing water during peak heating periods, if necessary. The system
also utilizes a water cooling tower to reject the heat energy from the
condenser water loop during periods of high cooling demand.
Water source heat pump units can be suspended in the ceiling plenum,
oor mounted behind walls or placed directly in the occupied space as
a console unit. There are also rooftop and unit ventilator type water
source heat pumps.
Water source heat pump systems generally cost less to install than central
built-up systems. They offer individual zone control with the added
exibility of being able to accommodate changes in location and sizes as
thermal zones or zone occupancy change. This system is often installed
in ceiling plenums, which frees up valuable oor space.
Another valuable benet of water source heat pumps is that they can
accommodate simultaneous calls from zones requiring heating or
cooling. Depending on the climate, outside air may require preheat or
cooling prior to being introduced to the unit. In the example of ceiling
mounted water source heat pumps, put outside air ducts near each unit
to improve indoor air quality.
Normally, multiple units serve an occupied space. This gives component
redundancy to the system so if one unit were to fail, the other units could
back it up until the unit was repaired. The packaged design of most unit
types allows quick change-out by service personnel so maintenance can
typically be performed off site.
As with any HVAC system, there is a negative side as the water source
heat pump system often requires higher maintenance costs than conven-
tional air side systems. The system also typically has a shorter replace-
ment life than other systems because of continuous fan and compressor
operation during heating and cooling modes. The system can also create
room noise since the compressor and fan are commonly located close
to the zone occupant. Placing units away from the occupied space and
ducting the supply air to the zone can minimize potential noise problems.
General Information
5
WSHP Loop Controller GPC-XP Guide

Overview
The GPC-XP Controller can be congured to control the water loop
to the individual water source heat pumps installed in a typical water
source heat pump system. The GPC-XP can operate stand-alone or be
used with the AZ 2 Control System to utilize the transfer of commonly
shared information , such as outside air temperature and system active
conditions over a communication network.
The main goal of the GPC-XP Loop Controller is to provide water ow
and to maintain the loop water temperature by monitoring either the Loop
Return Water Temperature or the Loop Supply Water Temperature. If
a higher temperature is required, a water heating device is enabled. If
the temperature needs to be lowered, a water cooling device is enabled.
The AZ 2 Controller can be congured to control individual water
source heat pumps. The AZ 2 Controller will work in conjunction with
the GPC-XP Loop Controller to send and receive data critical to an ef-
cient WSHP system.
Typical Sequence
On a typical system as is shown and congured in this manual the GPC-
XP WSHP Loop Controller waits for a Request to Run from an AZ 2
Controller on a Global Binary Channel or a Binary Contact Closure from
another source when the AZ 2 Controllers are not being used. Once the
request is received the GPC-XP energizes the Request to Run Relay and
the System Active relay. The System Pump (usually using a Lead/Lag
pump conguration) is then activated to initiate water ow in the system.
Once the System Pump is activated and Proof of Water Flow has been
determined a Global broadcast or 24 VAC from the System Active relay
is sent to the Heat Pumps to enable their compressors to run as needed.
The GPC-XP monitors the System Return Water Temperature or the
System Supply Water Temperature to determine if the water needs to
be heated or cooled to maintain the desired loop water temperature. The
typical conguration uses the Return Water Temperature to determine
the need for Heating or Cooling of the loop water.
Pump On/Off -Control
When a Request to Run is received, the GPC-XP Loop Controller
activates the System Pump to initiate water ow to the heat pumps
and other devices on the loop. The pumps can either be constant ow
or controlled by a VFD (see “Pump VFD Control”). If controlled by
a VFD, a water pressure transducer must be used for pump control. In
addition if the Request To Run goes away or if the Proof of Water Flow
is lost, the pump will turn off.
Typically the System Pumps are Lead/Lag controlled based on a user
denable number of hours of operation. If one pump exceeds the other
pump’s run time by this amount, the lead is changed until that pump
exceeds the rst pump’s run time by the same amount. This keeps both
pumps with roughly the same number of hours on each pump. The run-
ning pump is shut off at the same time the standby pump is energized,
this prevents any down time or alarms.
The GPC-XP Loop Controller monitors water ow in the loop with either
a Binary contact closure (BIN1) or a 0 to 50 PSI pressure transducer
from one of the analog inputs congured for this. The user can congure
the pressure setpoint that needs to be met to initiate the System Pump.
Pump VFD Control
The GPC-XP Loop Controller has 4 optional modulating output signals
available for control of pumps, boilers and cooling towers utilizing
VFD control. If the system is using a Pressure Transducer instead of a
pressure switch for System Pump control, the GPC-XP can monitor the
loop pressure and use a Reverse Acting PID Loop to maintain a user
dened Loop Pressure Setpoint.
The Loop Pressure is maintained by decreasing the signal output voltage
when the pressure exceeds the user dened setpoint plus the deadband
and increasing the voltage output signal with the pressure is below the
setpoint.
The pump relays are still activated and Lead/Lagged as described in the
previous section. Both output signals are enabled by their correspond-
ing relays.
Operation Of The WSHP Loop Controller
Operation
6WSHP Loop Controller GPC-XP Guide

Operation Of The WSHP Loop Controller
WSHP Unit Compressor Enable
If after the Lead/Lagged pump activates and Proof of Water Flow has
been established, the System Active relay is energized and when AZ
2 Controllers are being used for the WSHP units, a Global enable is
broadcast to the controllers letting them know to enable their compres-
sors. If using another control system for the WSHP units the System
Active relay would be used to send a 24 V relay signal to the units to run.
Heat Rejection
Staged Cooling
The GPC-XP Loop Controller monitors the loop water temperature to
determine if the loop water needs to be cooled. If the loop water tempera-
ture rises above a user dened setpoint the GPC-XP Loop Controller will
energize the cooling tower spray pump. This will remain on if the spray
pump proof of ow proves ow until the setpoint temperature is satised.
This acts as the rst stage of heat rejection. If the loop water temperature
continues to rises above a second set of user dened setpoints the cooling
tower fan will be energized providing a second stage of cooling for the
water owing through the cooling tower.
Modulating Cooling
The GPC-XP Loop Controller has the ability of sending a modulating
signal to the cooling tower fan if equipped with a VFD, to provide an
increase or decrease using a direct acting oating point control of the
output signal for modulating the cooling tower fan VFD.
Heat Addition
Staged Heating
The GPC-XP Loop Controller monitors the loop water temperature to
determine if the loop water needs to be heated. If the loop water tem-
perature falls below a user dened setpoint the GPC-XP Loop Control-
ler will energize the Cool Bypass Valve and enable the heat addition
device. This will remain on if the boiler proof of ow proves ow until
the setpoint temperature is satised.
Modulating Heating
The GPC-XP Loop Controller has the ability of sending a modulating
signal to a modulating mixing valve or a variable heat source. When
the loop water temperature drops below a user dened setpoint, the
Cool Bypass Valve will be energized and the analog output voltage
will increase or decrease using a reverse acting oating point control to
modulate a valve or variable heat source.
Emergency Shutdown
The GPC-XP Loop Controller uses an Emergency Shutdown input on
one of the binary inputs from a restat or smoke detector (by others) to
force shutdown of the entire system should a safety condition be initi-
ated by the safety device. It is congured as a Normally Closed (NC)
contact that is only active when the circuit is opened.
Operation
7
WSHP Loop Controller GPC-XP Guide

Controller, Sensors & Related Hardware
Components
GPC-XP Controller
OE338-23-GPCXP
The OE338-23-GPCXP Controller is used for controlling equipment or processes that cannot be controlled us-
ing a standard HVAC controller. The Prism 2 computer front end software is required to interface with the GPC-
XP controller functions. The GPC-XP Controller provides the exibility to control, schedule and/or monitor equip-
ment such as unit heaters, exhaust fans, motorized louvers, boilers, pumps and other mechanical equipment.
• 8 congurable analog inputs
• All analog inputs accept 10 K ohm thermistor sensors, 4-20 mA, 0-5 VDC or 0-10 VDC signals and
are set by means of jumpers on the controller
• Create custom formulas for analog inputs
• Highest/lowest/average of the analog inputs. Can be used in the internal logic or can be broadcast to
other controllers on the system
• 8 wet 24 VAC binary contacts which can be congured for N.O. or N.C. operation
• 8 congurable N.O. or N.C. relay outputs for On/Off control of equipment
• 4 analog outputs with proportional control signals. All selectable for 0-10 VDC output
• 8 separate 2 event per day time schedules which can be used for operational control or alarm
recognition based on time of day
• Lead/lag start capabilities.
Duct Temperature Sensor - 6” Probe
OE230
Used for return or supply air water sensing applications. 10k Ohm Duct Temperature Sensor, 2 wire. Used with
OE291 immersion well listed below
Immersion Well for OE230 Water Temperature Sensor
OE366
Includes: Stainless steel thermowell to be used with the OE230 Temperature Sensor listed above. The ther-
mowell is designed to thread into a ½″ FPT elbow or tee in the water piping system.
Strap-on Temperature Sensor Kit
OE233
10k Ohm Type 3, Strap-on Temperature Sensor, 2 wire. Used for water temperature sensing on outside of pipe.
Includes sensor, thermal mastic, and plastic mounting strap.
Outdoor Air Temperature Sensor
OE250
Used for temperature sensing applications. 10k Ohm Outside Air Temperature Sensor, 2 wire, mounted in a
weatherproof handy box only.
Outdoor Air Mounted RH Sensor 3% - 0-5 VDC Output
OE265-13
Used for outdoor air humidity sensing applications.
Water Differential Pressure Transducer
OE262
Includes: 0-5 VDC Differential Pressure Transducer and mounting bracket. The water pressure transducer
is used with the WSHP Loop Controller to detect water ow differential pressure in the system water loop.
Required when a VFD pump is used..
Water Differential Pressure Switch
OE261
Includes Differential Pressure Switch only. This SPDT switch is used with the WSHP Loop Controller to detect
ow in the system water loop.
8WSHP Loop Controller GPC-XP Guide

Optional Communication Devices and Software
Components
Note: The GPC-XP has its own USB port for direct connection to a desktop or laptop Windows based PC. For remote
communications via an internet connection or if you need to locate your PC further than the USB cable length allows,
you will need to consider the following devices listed in the table below. To congure and change setpoints on the
GPC-XP controller you will need to connect a Windows based PC or Laptop with WattMaster’s free Prism 2 software.
Information about the Prism 2 software is also listed in the table below
CommLink 5 Communications Interface
OE361-13
The CommLink 5 provides a PC connection to your AZ 2/GPC-XP network. If your GPC-XP Water
Source Controller is being used in conjunction with the Auto-Zone 2 Controls System, be sure to
consult the AZ 2 installation manual for wiring details.
Includes: CommLink 5, 6 ft. long USB cable, and 120/24 VAC power supply.
IP Module Kit - Internet/LAN Connection
OE415-02
Used for Internet or Local Area Network communications with the control system. Field installs by
plugging into the CommLink 5 circuit board and provides an addressable Ethernet connection to
the controls system from any computer connected to your building’s LAN. It can also be congured
to allow access to the control system from the Internet through your LAN if your Ethernet rewall is
congured for this option.
Includes: IP Link module, 10 ft. long Ethernet cable, and installation instructions.
MiniLink 5
OE364-23-AZ2
Used with all AZ 2 Controllers to provide network communications, zone voting, alarming, and ten-
ant logging capabilities.
USB-Link II Kit
OE366
The IP Module provides Internet or Local Area Network connectivity to the CommLink 5. Simply
install the IP Module into your CommLink 5 and congure per the installation guide.
Includes: USB-Link, USB cable, modular connection cable, two mini-DIN to terminal adapters, and
Prism 2 software.
Prism 2 Front-End Computer Software
Free!
Prism 2 provides standard, easy to understand status screens for each type of AZ 2 equipment
installed. Prism software has provisions for custom screens which allow oor plans, equipment
photos, or user-dened summary screens to be implemented to meet their own individual needs.
All controlling setpoints, trend logs, and alarm conditions are accessed in the Prism 2 environment.
Prism 2 can be congured for direct on-site installation, remote modem connection, or TCP/IP
Internet connection to several installations.
Free Download
From AZ 2 Web Site
www.az2controls.com
9
WSHP Loop Controller GPC-XP Guide

Communication, Baud Rate Settings & Wiring Info
Before Applying Power
In order to have a trouble free start-up, it is important to follow a few
simple procedures. Before applying power for the rst time, it is very
important to correctly address the controller and run through a few
simple checks.
System Settings
Stand Alone Operation
The GPC-XP has an on-board CommLink that is used during Stand-
Alone Operation. When configured for Stand-Alone operation, a
computer running Prism 2 software can be connected directly to the
USB port located at the bottom of the GPC-XP for programming and
monitoring. In order to operate in Stand-Alone Mode, two things need
to be set. First, both CommLink Jumpers found on the upper left-hand
side of the board need to be set to ON. See Figure 4 for details. Second,
the Baud Rate is determined by setting ADDRESS Dipswitch 7 to ON
and Dipswitch 8 to OFF. See Figure 5 for details.
Network Operation
The GPC-XP can be congured for connection to a networked system
that has an external CommLink. In this case, the on-board CommLink
would not be used. For this conguration, two things need to be set.
First, both CommLink Jumpers found on the upper left-hand side of the
board need to be set to OFF. See Figure 4 for details. Second, the Baud
Rate determined by setting ADDRESS Dipswitches 7 and 8 needs to
be set to OFF/OFF if using a CommLink IV and to OFF/ON if using a
CommLink 5. See Figure 5 for details.
Controller Addressing & Baud Rate
The GPC-XP Controller is equipped with address switches. When using
Prism 2 to program and congure the GPC-XP Controller, you would
enter this address to communicate with the controller. When the system
is to be connected to other HVAC unit controllers on a communication
loop, each controller’s address switch must be set with a unique address
between 1 and 59.
Settings
Important Wiring Considerations
Please read carefully and apply the following information when wiring
the GPC-XP Controller:
1. To operate the GPC-XP Controller, you must connect power to
the 24 VAC input terminal block.
2. Check all wiring leads at the terminal block for tightness.
Be sure that wire strands do not stick out and touch adjacent
terminals. Conrm that all sensors required for your system are
mounted in the appropriate location and wired into the correct
terminals. See Figure 6 & 7 for wiring connections drawings.
Environmental Requirements
The GPC-XP Controller needs to be installed in an environment that can
maintain a temperature range between -30°F and 150°F and not exceed
90% RH levels (non-condensing).
Mounting
The GPC-XP Controller is housed in a plastic enclosure. It is designed
to be mounted by using the 3 mounting holes in the enclosure base. It is
important to mount the module in a location that is free from extreme high
or low temperatures, moisture, dust, and dirt. Be careful not to damage
the electronic components when mounting the module.
Power Supply
The GPC-XP Controller requires a 24 VAC power connection with a
minimum rating of 8 VA.
WARNING: Observe polarity! All boards must be wired
GND-to-GND and 24 VAC-to-VAC. Failure to
observe polarity could result in damage to the
boards.
Figure 3 GPC-XP Controller Dimensions
10 WSHP Loop Controller GPC-XP Guide