Johnson Controls RH Series Engineering Manual
FORM 146.00-EG5 (616)
MODEL RH
GEOTHERMAL HYDRONIC HEAT PUMP
ENGINEERING GUIDE
1.5–6 Tons
R-410A Refrigerant
Table of Contents
Model Nomenclature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4
The Hydronic Unit. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5-6
Inside the Hydronic Unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
Water Quality . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
The Aurora Base Control System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9-12
Application Notes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13-19
Dimensional Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20
Physical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Electrical Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
Antifreeze Correction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
RH SERIES ENGINEERING GUIDE
AHRI/ISO 13256-2 Performance Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
Pressure Drop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .24
Reference Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Legend and Notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
Performance Data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .26-39
Wiring Schematics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40-45
Accessories and Options. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .46-47
Engineering Guide Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48-49
Revision Guide. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
RH SERIES ENGINEERING GUIDE
Model Nomenclature
1-4
5-7 8 9 10 11 12
RHSW 050 R 0 0 A C
Model
RHSW – RH Series Hydronic
Heat Pump
Unit Capacity
018, 025, 040, 050, 060, 075
Reversible Option
H- Heating Only
R- Reversible
Voltage
0 – 208-230/60/1 (Commercial)
2 – 265/60/1 (025 & 050 only)
3 – 208-230/60/3 (040-075)
4 – 460/60/3 (025-075)
5 – 575/60/3 (040-075)
Hot Water Option
0 – No Hot Water Generation, No IntelliStart
2 – Hot Water Generation, No IntelliStart
3 – No Hot Water Generation, IntelliStart
5 – Hot Water Generation, IntelliStart
1,3
13
C
14-15
SS *
16
Vintage
* – Factory Use Only
Future Option
SS – Standard
Load Coax
C – Copper
N – Cupronickel
Source Coax
C – Copper
N – Cupronickel
Controls Option
A – Aurora™ Base Controls (ABC)
Rev.: 10 June 2016
2
NOTES: 1 – Available on 040, 050, 060, and 075 only. Hot water generator requires field installed external pump kit.
2 – 018 and 025 heating only models are available only with copper double wall vented load coax for potable water,
and are not designed to be converted to dedicated cooling units.
3 – IntelliStart not available on 265/60/1 and 575/60/3 voltages.
RH Series hydronic units are Safety listed under UL1995 thru ETL and performance tested in accordance
with standard AHRI/ISO 13256-2. AHRI does not currently certify water-to-water products under AHRI/
ISO 13256-2.
4
4
The Single Hydronic Series
RH SERIES ENGINEERING GUIDE
Features
High efficiency copper coaxial
heat exchanger (vented
double walled available only
on 018 and 025 "heating only"
models)
Optional IntelliStart
reduces starting current
by 60-70%
Field switchable control
box (end to end) for
application flexibility
Insulated and corrosion
resistant cabinet to
reduce noise
Aurora controls
Aurora "Base" Controls
Dual isolation compressor
mounts to reduce noise
and vibration
Captive FPT water connections
eliminate 'egg-shaping' backup
Discharge Muffler Helps
quiet compressor gas
pulsations
Zero ODP and low GWP
R-410A refrigerant
Optional Hot Water
Generator available on
040-075
High efficiency copper or
cupronickel coaxial heat
exchangers
Full refrigerant suction
tube, heat exchanger, and
waterline insulation to prevent
condensation at low loop
temperatures
High efficiency scroll
compressors for improved
reliability
Compressor sound
blankets for reduced noise
Standard waterlines out the
front (field switchable to back
via control box)
wrench
What’s New?
• AuroraTM Communicating Control Features
- Traditional Safety Sensors: HP, LP, condensate overflow,
freeze detection loop, freeze detection load.
- Communicating Modular Design: Communicating modular
design for flexibility and expandability
5
RH SERIES ENGINEERING GUIDE
Single Hydronic Series cont.
High Efficiency
Large oversized water-to-water refrigerant heat exchangers and
scroll compressors provide extremely efficient operation. The
Aurora Controls extend this innovation and performance.
Operating Efficiencies
• Environmentally friendly R-410A refrigerant reduces
ozone depletion.
• An optional hot water generator is available on 040,
050, 060, and 075 to generate hot water at considerable
savings while improving overall system efficiency.
• High-stability bidirectional expansion valve provides
superior performance.
• Efficient scroll compressors operate quietly.
• Oversized coaxial tube water-to-refrigerant heat
exchanger increases efficiency.
Standard Features
• Heavy gauge cabinet
• Quiet scroll compressors in all models
• All interior cabinet surfaces are insulated with
[12.7 mm] thick 1
1
⁄2 lb. [681 g] density, surface coated,
1
⁄2 in.
acoustic type glass fiber insulation.
• Optional IntelliStart
®
to reduce starting current
(208-230/60/1)
• Field switchable control box
• Ultra-compact cabinet
• Multi-density laminate lined compressor blanket designed
to suppress low frequency noise.
• Discharge line mufflers to help quiet compressor
discharge gas pulsations.
Product Quality
• Heavy-gauge steel cabinets are finished with a durable
polyester powder coat paint for long lasting beauty
and service.
• All refrigerant brazing is performed in a nitrogen atmosphere.
• The 018H and 025H are available with load side copper
vented double wall coaxial heat exchangers.
• Coaxial heat exchangers, refrigerant suction lines, hot water
generator, and all water pipes are fully insulated to reduce
condensation problems in low temperature operation.
• Computer controlled deep vacuum and refrigerant
charging system.
• All joints are leak detected for maximum leak rate of
less than
• Computer bar code equipped assembly line ensures all
components are correct.
• All units are computer run-tested with water to verify
both function and performance.
• Safety features include high- and low-pressure refrigerant
controls to protect the compressor; hot water high-limit
hot water generator pump shutdown.
1
⁄4 oz. per year.
Easy Maintenance and Service Advantages
• Removable compressor access panels.
• Quick attach wiring harnesses are used throughout for
fast servicing.
• High and low pressure refrigerant service ports.
Options and Accessories
• Optional hot water generator with externally mounted
pump (230/60/1) and water heater plumbing connector.
• Closed loop, source side, circulating pump kit
• Closed loop, load side, circulating pump kit
• Water connection kits
• Geo-Storage Tank (80-120 Gal.)
• IntelliStart
• HydroZone, tank control with outdoor reset
• HydroLogic
• HydroStat, communicating set point control
Application Flexibility
• Designed to operate with entering source temperature of
25°F and leaving load temperatures of 40°F to 130°F. See
the capacity tables to see allowable operating conditions
per model.
• Source side flow rates as low as 1.5 GPM/ton for well
water, 50°F [10°C] min. EWT.
• Dedicated heating and heat pump models available.
• Dedicated non-reversible models are shipped as
heating only; field convertible to cooling only.
• Modularized unit design and primary/secondary
controls for optimum capacity matching and staging.
• Stackable for space conservation (to a maximum 3
units high).
• Compact size allows installation in confined spaces.
• Front or rear plumbing connections.
• Control Panel location is reversible.
6
Inside The Single Hydronic Series
RH SERIES ENGINEERING GUIDE
Refrigerant
Our products all feature zero ozone depletion and low
global warming potential R-410A refrigerant.
Cabinet
All units are constructed of corrosion resistant galvanized
sheet metal with powder coat paint rated for more than
1000 hours of salt spray. Lift-out access panels provide
access to the compressor section from two sides.
Compressors
High efficiency R-410A scroll compressors are used on every
model. Scrolls provide both the highest efficiency available
and great reliability.
Electrical Box
The control box is "field" movable from front to back for ease
of application. Separate knockouts for low voltage, and two
for power on, front and back, allow easy access to the control
box. Large 75VA transformer assures adequate controls power
for accessories.
Water Connections
Flush mount FPT water connection fittings allow one wrench
leak-free connections and do not require a backup wrench.
Factory installed water line thermistors can be viewed through
the microprocessor interface tool.
Thermostatic Expansion Valve
All models utilize a balanced port
bidirectional thermostatic expansion
valve (TXV) for refrigerant metering.
This allows precise refrigerant flow in a
wide range of entering water variation
(25 to 120°F [-7 to 49°C]) found in
geothermal systems. The TXV is located
in the compressor compartment for easy
access.
Service Connections and
Serviceability
Two Schrader service ports are
provided for each unit. The suction
side and discharge side ports are for
field charging and servicing access. All
valves are 7/16 in. SAE connections.
4-Way Reversing Valve
Units feature a reliable all-brass pilot operated refrigerant
reversing valve. The reversing valve operation is limited to
change of mode by the control to enhance reliability.
IntelliStart
The optional IntelliStart single
phase soft starter will reduce
the normal start current (LRA)
by 60-70%. This allows the
heat pump to go off-grid.
Using IntelliStart also provides
a substantial reduction in
light flicker, reduces start-up noise, and improves the
compressor's start behavior. IntelliStart is available in a field
retrofit kit or as a factory installed option. IntelliStart is
available on 208-230/60/1 voltage.
Water-to-Refrigerant Heat Exchanger Coil
Large oversized coaxial refrigerantto-water heat exchangers provide
unparalleled efficiency. The coaxes
are designed for low pressure drop
and low flow rates. All coaxes are
pressure rated to 450 psi water side
and 600 psi on the refrigerant side.
Refrigerant-to-water heat exchangers
will be coated with ThermaShield
to prevent condensation in low
temperature loop operation. Vented,
double walled heat exchanger suitable
for potable water systems are standard
on 018-025 heating only models.
7
RH SERIES ENGINEERING GUIDE
Water Quality
General
Water-to-water heat pumps may be successfully applied
in a wide range of residential and light commercial
applications. It is the responsibility of the system designer
and installing contractor to ensure that acceptable water
quality is present and that all applicable codes have been
met in these installations. Failure to adhere to the guidelines
in the water quality table could result in loss of warranty.
Application
These heat pumps are not intended for direct coupling to
swimming pools and spas. If used for this type of application, a secondary heat exchanger must be used. Failure to
supply a secondary heat exchanger for this application will
result in warranty exclusion for primary heat exchanger corrosion or failure.
Water Treatment
Do not use untreated or improperly treated water.
Equipment damage may occur. The use of improperly
treated or untreated water in this equipment may result in
scaling, erosion, corrosion, algae or slime. The services of a
qualified water treatment specialist should be engaged to
determine what treatment, if any, is required. The product
warranty specifically excludes liability for corrosion,
erosion or deterioration of equipment.
The heat exchangers and water lines in the units are copper
or cupronickel tube. There may be other materials in the
building’s piping system that the designer may need to take
into consideration when deciding the parameters of the
water quality.
If an antifreeze or water treatment solution is to be used,
the designer should confirm it does not have a detrimental
effect on the materials in the system.
Contaminated Water
In applications where the water quality cannot be held to
prescribed limits, the use of a secondary or intermediate
heat exchanger is recommended to separate the unit from
the contaminated water.
The following table outlines the water quality guidelines
for unit heat exchangers. If these conditions are exceeded,
a secondary heat exchanger is required. Failure to supply
a secondary heat exchanger where needed will result in a
warranty exclusion for primary heat exchanger corrosion
or failure.
WARNING: Must have intermediate heat
exchanger when used in pool and spa
applications.
Water Quality Guidelines
Material Copper 90/10 Cupronickel 316 Stainless Steel
pH Acidity/Alkalinity
Scaling
Corrosion
Iron Fouling
(Biological Growth)
Erosion
NOTES: Grains = ppm divided by 17
mg/L is equivalent to ppm
Calcium and
Magnesium Carbonate
Hydrogen Sulfide
Chlorine Less than 0.5 ppm Less than 0.5 ppm Less than 0.5 ppm
Chlorides Less than 20 ppm Less than 125 ppm Less than 300 ppm
Carbon Dioxide Less than 50 ppm 10 - 50 ppm 10 - 50 ppm
Ammonia Less than 2 ppm Less than 2 ppm Less than 20 ppm
Ammonia Chloride Less than 0.5 ppm Less than 0.5 ppm Less than 0.5 ppm
Ammonia Nitrate Less than 0.5 ppm Less than 0.5 ppm Less than 0.5 ppm
Ammonia Hydroxide Less than 0.5 ppm Less than 0.5 ppm Less than 0.5 ppm
Ammonia Sulfate Less than 0.5 ppm Less than 0.5 ppm Less than 0.5 ppm
Total Dissolved Solids (TDS) Less than 1000 ppm 1000 - 1500 ppm 1000 - 1500 ppm
LSI Index +0.5 to -0.5 +0.5 to -0.5 +0.5 to -0.5
Iron, FE
Bacterial Iron Potential
Iron Oxide
Suspended Solids
Threshold Velocity
(Fresh Water)
Less than 0.5 ppm (rotten egg
Sulfates Less than 125 ppm Less than 125 ppm Less than 200 ppm
2
+ (Ferrous)
smell appears at 0.5 ppm)
Less than 1 ppm, above this
level deposition will occur
Less than 10 ppm and filtered
for max. of 600 micron size
7 - 9 7 - 9 7 - 9
(Total Hardness)
less than 350 ppm
< 0.2 ppm < 0.2 ppm < 0.2 ppm
< 6 ft/sec < 6 ft/sec < 6 ft/sec
(Total Hardness)
less than 350 ppm
10 - 50 ppm Less than 1 ppm
Less than 1 ppm, above this
level deposition will occur
Less than 10 ppm and filtered
for max. of 600 micron size
(Total Hardness)
less than 350 ppm
Less than 1 ppm, above this
level deposition will occur
Less than 10 ppm and filtered
for max. of 600 micron size
2/22/12
8
RH SERIES ENGINEERING GUIDE
The Aurora Base Control System
Aurora ‘Base’ Control
The Aurora ‘Base’ Control (ABC) System is a complete residential and commercial comfort
system that brings all aspects of the HVAC system into one cohesive module network. The
ABC features microprocessor control and HP, LP, condensate and freeze detection, over/
under voltage faults, along with communicating thermostat capability for complete fault
detection text at the thermostat.
Aurora uses the Modbus communication protocol to communicate between modules. Each
module contains the logic to control all features that are connected to the module. The
Aurora ‘Base’ Control (ABC) has two Modbus channels. The rst channel is congured as a
master for connecting to devices such as a communicating thermostat, expansion board, or other satellite devices. The second
channel is congured as a satellite for connecting the Aurora Interface Diagnostics T
Aurora Control Features Description Aurora ‘Base’
Microprocessor Compressor Control
Base Hot Water Generator
Operation
Base Loop Pump Control
Microprocessor control of compressor for timings with FP1, HP,
LP, Condensate, assignable Acc relay
Compressor Contactor powers Hot Water Generator Pump with
inline circuit breaker and thermostat limit.
Compressor Contactor powers Loop Pump with inline circuit
breaker and no loop pump linking capability.
ool (AID Tool).
•
•
•
Service Device Description Aurora ‘Base’
Allows setup, monitoring and troubleshooting of any
Aurora Control.
NOTE: Although the ABC has basic compatibility with all
Aurora, new product features may not be available on older
AID Tools. To simplify the basic compatibility ensure the
Aurora Interface and Diagnostics
(AID) Tool
Add On Thermostats and Zoning Description Aurora ‘Base’
HydroStat
HZO
HZC
version of AID is at least the same or greater than the ABC
software version.
Communicating controller for one hydronic heat pump. Optional
Non-communicating controller for up to four heat pumps. Optional
Non-communicating controller for one hydronic heat pump Optional
For Service
(Ver. 1.xx or greater)
9
RH SERIES ENGINEERING GUIDE
The Aurora Base Control System cont.
Aurora ‘Base’ Control
NOTE: Refer to the Aurora Base Control Application and
Troubleshooting Guide and the Instruction Guide: Aurora
Interface and Diagnostics (AID) Tool for additional information.
Control Features
• Random start at power up
• Anti-short cycle protection
• High and low pressure cutouts
• Loss of charge
• Water coil freeze detection
• Over/under voltage protection
• Load shed
• Emergency shutdown
• Diagnostic LED
• Test mode push button switch
• Alarm output
• Accessory output with N.O. and N.C.
• Modbus communication (master)
• Modbus communication (satellite)
Field Selectable Options via Hardware
DIP Switch (SW1) – Test/Conguration Button (See SW1
Operation Table)
Test Mode
The control is placed in the test mode by holding the push
button switch SW1 for 2 - 5 seconds. In test mode most of
the control timings will be shortened by a factor of sixteen
(16). LED3 (green) will ash at 1 second on and 1 second
o. Additionally, when entering test mode LED1 (red) will
ash the last lockout one time. Test mode will automatically
time out after 30 minutes. Test mode can be exited by
pressing and holding the SW1 button for 2 to 5 seconds or
y cycling the power. NOTE: Test mode will automatically
b
be exited after 30 minutes.
Reset Conguration Mode
The control is placed in reset conguration mode by
holding the push button switch SW1 for 50 to 60 seconds.
This will reset all conguration settings and the EEPROM
back to the factory default settings. LED3 (green) will turn
o when entering reset conguration mode. Once LED3
(green) turns o, release SW1 and the control will reset.
DIP Switch (SW2)
SW2-1 (Source) FP1 Selection – Low water coil temperature
limit setting for freeze detection. On = 30°F;
O = 15°F.
SW2-2 (Load) FP2 Selection – On = 30°F; O = 15 ° F
SW2-3 RV – O/B - thermostat type. Heat pump
thermostats with “O” output in cooling or “B”
output in Heating can be selected. On = O; O = B.
SW2-4 Access Relay Operation (P2)
and 2-5
Access Relay Operation SW2-4 SW2-5
Cycle with Blower n/a
Cycle with Compressor OFF OFF
Water Valve Slow Opening ON OFF
Cycle with Comm. T-stat Hum Cmd n/a
Cycle with Blower - (Not used on water-to-water)
Cycle with Compressor - The accessory relay will cycle
with the compressor output.
Water Valve Slow Opening - The accessory relay will
cycle and delay both the blower and compressor output
for 90 seconds.
SW2-6 CC Operation – selection of single or dual capacity
compressor. On = Single Stage; O = Dual Capacity
SW2-7 Lockout and Alarm Outputs (P2) – selection of a
continuous or pulsed output for both the LO and
ALM Outputs. On = Continuous; O = Pulsed
SW2-8 Future Use
Alarm Jumper Clip Selection
From the factory, ALM is connected to 24 VAC via JW2. By
cutting JW2, ALM becomes a dry contact connected to ALG.
Field Selectable Options via Software
(Selectable via the Aurora AID Tool)
Safety Features
The following safety features are provided to protect the
compressor, heat exchangers, wiring and other components
from damage caused by operation outside of design conditions.
Fuse – a 3 amp automotive type plug-in fuse provides
protection against short circuit or overload conditions.
Anti-Short Cycle Protection – 4 minute anti-short cycle
protection for the compressor.
Random Start – 5 to 80 second random start upon power up.
10
The Aurora Base Control System cont.
RH SERIES ENGINEERING GUIDE
Fault Retry – in the fault condition, the control will stage off
the outputs and then “try again” to satisfy the thermostat
Y input call. Once the thermostat input calls are satisfied,
the control will continue on as if no fault occurred. If 3
consecutive faults occur without satisfying the thermostat
Y input call, then the control will go to Lockout mode.
Lockout – The Alarm output (ALM) and Lockout output (L)
will be turned on. The fault type identification display LED1
(Red) shall flash the fault code. To reset lockout conditions
with SW2-8 On, thermostat inputs “Y1”, “Y2”, and “W”
must be removed for at least 3 seconds. To reset lockout
conditions with SW2-8 Off, thermostat inputs “Y1”, “Y2”,
“W”, and “DH” must be removed for at least 3 seconds.
Lockout may also be reset by turning power off for at least
30 seconds or by enabling the emergency shutdown input
for at least 3 seconds.
High Pressure – fault is recognized when the Normally
Closed High Pressure Switch, P4-9/10 opens, no matter
how momentarily. The High Pressure Switch is electrically in
series with the Compressor Contactor and serves as a hardwired limit switch if an overpressure condition should occur.
Low Pressure - fault is recognized when the Normally
Closed Low Pressure Switch, P4-7/8 is continuously open
for 30 seconds. Closure of the LPS any time during the 30
second recognition time restarts the 30 second continuous
open requirement. A continuously open LPS shall not be
recognized during the 2 minute startup bypass time.
Loss of Charge – fault is recognized when the Normally
Closed Low Pressure Switch, P4-7/8 is open prior to the
compressor starting.
Freeze Detection (Source Coax) - set points shall be
either 30°F or 15°F. When the thermistor temperature
drops below the selected set point, the control shall begin
counting down the 30 seconds delay. If the thermistor
value rises above the selected set point, then the count
should reset. The resistance value must remain below the
selected set point for the entire length of the appropriate
delay to be recognized as a fault. This fault will be ignored
for the initial 2 minutes of the compressor run time.
Freeze Detection (Load Coax) - uses the FP2 input to
protect against ice formation on the coax. The FP2 input
will operate exactly like FP1.
Over/Under Voltage Shutdown - An over/under voltage
condition exists when the control voltage is outside the
range of 18 VAC to 30 VAC. If the over/under voltage
shutdown lasts for 15 minutes, the lockout and alarm relay
will be energized. Over/under voltage shutdown is selfresetting in that if the voltage comes back within range
of 18 VAC to 30 VAC for at least 0.5 seconds, then normal
operation is restored.
Operation Description
Power Up - The unit will not operate until all the inputs and
safety controls are checked for normal conditions. The unit
has a 5 to 80 second random start delay at power up. Then
the compressor has a 4 minute anti-short cycle delay after
the random start delay.
Standby In standby mode, Y1, Y2, W, DH, and G are not
active. Input O may be active. The blower and compressor
will be off.
Heating Operation
Heating, 1st Stage (Y1) - The compressor is energized 10
seconds after the Y1 input is received.
Cooling Operation
In all cooling operations, the reversing valve directly tracks
the O input. Thus, anytime the O input is present, the
reversing valve will be energized.
Cooling, 1st Stage (Y1, O) - The compressor is energized 10
seconds after the Y1 input is received.
Emergency Shutdown - Four (4) seconds after a valid ES
input, P2-7 is present, all control outputs will be turned off
and remain off until the emergency shutdown input is no
longer present. The first time that the compressor is started
after the control exits the emergency shutdown mode,
there will be an anti-short cycle delay followed by a random
start delay. Input must be tied to common to activate.
Load Shed - The LS input disables all outputs with the
exception of the blower output. When the LS input has been
cleared, the anti-short cycle timer and random start timer
will be initiated. Input must be tied to common to activate.
11
RH SERIES ENGINEERING GUIDE
The Aurora Base Control System cont.
Aurora ‘Base’ Control LED Displays
These three LEDs display the status, configuration, and
fault codes for the control. These can also be read in plain
English via the Aurora AID Tool.
Status LED (LED3, Green)
Description of Operation Fault LED, Green
Normal Mode ON
Control is Non-functional OFF
Test Mode Slow Flash
Lockout Active Fast Flash
Dehumidification Mode Flash Code 2
(Future Use) Flash Code 3
(Future Use) Flash Code 4
Load Shed Flash Code 5
ESD Flash Code 6
(Future Use) Flash Code 7
Fault LED (LED1, Red)
Red Fault LED
LED Flash
Code*
Lockout
Normal - No Faults OFF –
Fault - Input 1 No Auto
Fault - High Pressure 2 Yes Hard or Soft
Fault - Low Pressure 3 Yes Hard or Soft
Fault - Freeze Detection FP2 4 Yes Hard or Soft
Fault - Freeze Detection FP1 5 Yes Hard or Soft
Fault - Condensate Overflow 7 Yes Hard or Soft
ABC Basic Faults
Fault - Over/Under Voltage 8 No Auto
Fault - FP1 & FP2 Sensor Error 11 Yes Hard or Soft
NOTE: All codes >11 use long flash for tens digit and short flash for the ones
digit. 20, 30, 40, 50, etc. are skipped.
Reset/
Remove
ABC Control Board Layout
C
CFM
CC
Y1
CC2
CC2
F
G
JW2 Alarm
FP2
FP2
FP1
FP1
REV
REV
CCG
PWM
HP
HP
LP
LP
G
LO
HI
CC
FG
F
R
ECM PWM
P4
P13
Fact ory
SW1 Test
RV – K1
CC – K2
P5
P2
ES
CC Hi – K3
Fact ory
Fan – K4
Alarm – K5
Acc – K6
LS
ALG
ALM
ACC c
ACC n c
ACC n o
FP1 – 15oF/30oF
FP2 – 15
RV – B/O
Fault
ACC – Dip 4
CC – Dual/Single
G
L – Pulse/Continuous
Status
ACC – Dip 5
Reheat/Normal
LED3
AURORA BASE
CONTROL™
Fact ory Use
P11
P9
Factory Fan Connection
C
R
LO
O/B
Field ConnectionsField Connections
P1
R
C
LO
O/B
o
F/30oF
G
G
Y1
Y1
Off
On
LED2LED1
1
YR
2
3
Config
4
5
6
7
8
SW2
Com1
Com2
W
Y2
DH
W
Y2
DH
3A-Fuse
G
G
RR
EH1
EH2
P3
C
EH1
C
Fact ory
CO
N/A
(+)
P6
(-)
R
RS485 Exp
C
P7
RS 485
P8
RS485 NET
CC
C
Aurora Interface and Diagnostics (AID) Tool
The Aurora Interface and
Diagnostics (AID) Tool is
a device that is a member
of the Aurora network.
The AID Tool is used to
troubleshoot equipment
which uses the Aurora
control via Modbus RTU
communication. The AID
Tool provides diagnostics,
fault management, ECM
setup, and system configuration capabilities to the Aurora
family of controls. An AID Tool is recommended, although
not required, for ECM airflow settings. The AID Tool simply
plugs into the exterior of the cabinet in the AID Tool port.
12
Application Notes
RH SERIES ENGINEERING GUIDE
The Closed Loop Heat Pump Concept
The basic principle of a water source heat pump is the
transfer of heat into water from the space during cooling,
or the transfer of heat from water into the space during
heating. Extremely high levels of energy efficiency are
achieved as electricity is used only to move heat, not to
produce it. Using our typical water-to-water heat pump one
unit of electricity will move four to five units of heat.
When multiple water source heat pumps are combined
on a common circulating loop, the ultimate in energy
efficiency is created: The water-to-water units on cooling
mode are adding heat to the loop which the units in
heating mode can absorb, thus removing heat from the
area where cooling is needed, recovering and redistributing
that heat for possible utilization elsewhere in the system.
In modern commercial structures, this characteristic of
heat recovery from core area heat generated by lighting,
office equipment, computers, solar radiation, people or
other sources, is an important factor in the high efficiency
and low operating costs of our closed source heat pump
systems.
Return Water
Water-to-water
Unit
Water-to-water
Unit
low because units can be added to the loop on an "as
needed basis"- perfect for speculative buildings. Installed
costs are low since units are self-contained and can be
located adjacent to the occupied space, requiring minimal
ductwork. Maintenance can be done on individual units
without system shut-down. Conditions remain comfortable
since each unit operates separately, allowing cooling in
one area and heating in another. Tenant spaces can be
finished and added as needed. Power billing to tenants
is also convenient since each unit can be individually
metered: each pays for what each uses. Nighttime and/or
weekend uses of certain areas are possible without heating
or cooling the entire facility. A decentralized system also
means if one unit should fault, the rest of the system will
continue to operate normally, as well as eliminating air
cross-contamination problems and expensive high pressure
duct systems requiring an inefficient electric resistance
reheat mode.
The Best Approach
There are a number of proven choices in the type of system
which would be best for any given application. Most often
considered are:
Vertical - Closed Loop/Ground Source
Heater/
Rejector
Pumps
Water-to-water
Unit
Water-to-water
Unit
Supply Water
Water-to-water
Unit
Water-to-water
Unit
In the event that a building's net heating and cooling
requirements create loop temperature extremes, our
units have the extended range capacity and versatility to
maintain a comfortable environment for all building areas.
Excess heat can be stored for later utilization or be added
or removed in one of three ways; by ground-source heat
exchanger loops: plate heat exchangers connected to other
water sources, or conventional cooler/boiler configurations.
Your sales representative has the expertise and computer
software to assist in determining optimum system type for
specific applications.
The Closed Loop Advantage
A properly applied water source heat pump system offers
many advantages over other systems. First costs are
• Closed Loop/Ground-Source Systems utilize the stable
temperatures of the earth to maintain proper water source
temperatures (via vertical or horizontal closed loop heat
exchangers) for our extended range heat pump system.
Sizes range from a single unit through many hundreds of
units. When net cooling requirements cause closed loop
water temperatures to rise, heat is dissipated into the
cooler earth through buried high strength plastic pipe "heat
exchangers." Conversely if net space heating demands
cause loop heat absorption beyond that heat recovered
from building core areas, the loop temperature will fall
causing heat to be extracted from the earth. Due to the
extended loop temperatures, AHRI/ISO 13256-1 Ground
Loop Heat Pumps are required for this application.
13
RH SERIES ENGINEERING GUIDE
Application Notes cont.
Because auxiliary equipment such as a fossil fuel boiler
and cooling tower are not required to maintain the loop
temperature, operating and maintenance costs are very
low. Ground-source systems are most applicable in
residential and light commercial buildings where both
heating and cooling are desired, and on larger envelope
dominated structures where core heat recovery will not
meet overall heating loads. Both vertical and horizontally
installed closed-loops can be used. The land space
required for the "heat exchangers" is 100-250 sq. ft./ton
on vertical (drilled) installations and 750-1500 sq. ft./ton
for horizontal (trenched) installations. Closed loop heat
exchangers can be located under parking areas or even
under the building itself.
On large multi-unit systems, sizing the closed loop heat
exchanger to meet only the net heating loads and assisting
in the summer with a closed circuit cooling tower may be
the most cost effective choice.
Surface Water - Closed Loop/Ground Source
Plate Heat Exchanger - Closed Loop/Ground Water
• Closed Loop/Ground Water Plate Heat Exchanger
Systems utilize lake, ocean, well water or other water
sources to maintain closed loop water temperatures in
multi-unit systems. A plate frame heat exchanger isolates
the units from any contaminating effects of the water
source, and allows periodic cleaning of the heat exchanger
during off peak hours.
Operation and benefits are similar to those for groundsource systems. Due to the extended loop temperatures,
AHRI/ISO 13256-1 Ground Loop Heat Pumps are required
for this application. Closed loop plate heat exchanger
systems are applicable in commercial, marine, or industrial
structures where the many benefits of a water source heat
pump system are desired, regardless of whether the load is
heating or cooling dominated.
• Closed Loop/Ground-Source Surface Water Systems also
utilize the stable temperatures of Surface Water to maintain
proper water source temperatures for our extended
range heat pump systems. These systems have all of the
advantages of horizontal and vertical closed loop systems.
Due to the extended loop temperatures, AHRI/ISO 13256-1
Ground Water or Ground Loop Heat Pumps are required for
this application.
In cooling dominated structures, the ground-source surface
water systems can be very cost effective especially where
local building codes require water retention ponds for
short term storage of surface run-off. Sizing requirements
for the surface water is a minimum of 500 sq. ft./ton of
surface area at a minimum depth of 8 feet. Your sales
representative should be contacted when designs for
heating dominated structures are required.
14
Application Notes cont.
RH SERIES ENGINEERING GUIDE
Cooler/Boiler - Closed Loop
• Closed Loop /Cooler-Boiler Systems utilize a closed heat
recovering loop with multiple water source heat pumps
in the more conventional manner. Typically a boiler is
employed to maintain closed loop temperatures above
60°F and a cooling tower to maintain loop temperatures
below 90°F. These systems are applicable in medium
to large buildings regardless of whether the load is
heating or cooling dominated. Due to the moderate loop
temperatures, AHRI/ISO 13256-1 Water Loop Heat Pumps
are required for this application.
Typical Application Piping
30 psi
RELIEF VALVE
Back Flow Preventer /
Pressure Relief Valve
Dielectric
Unions
Dielectric
Unions
NOTES:
* A 30 psi pressure relief valve (Part No: SRV30) should be used in
hydronic applications.
** Vent valve or P/T port at highest point in return line prior to ball valve.
Pressure
Gauge
GEO
STORAGE
TANK
1-1/2 in.
FPT
Dip Tube
Ball Valve
Expansion
Tank
Air
Vent
Air
Separator
Ball Valve
LOAD PUMP
FROM
HWG
5 Series
Hydronic Unit
TO
HWG
HYDRONIC
PUMP
Source OUT
P/T PortsP/T Ports
Source IN
LOAD
HOT
(Piped in
series to
an electric
water heater)
Vent Valve/
P/T Port**
DOMESTIC
COLD
15
RH SERIES ENGINEERING GUIDE
Application Notes cont.
Heating with hot water is versatile because there are many
ways of distributing the heat through the building. The
options range from heavy cast iron radiators seen in older
buildings to modern, baseboard-style convection radiation,
and from invisible radiant floor heating to forced air
systems using fan coil units.
A boiler is often used to make domestic hot water and to
heat swimming pools or hot tubs.
The various distribution systems have all been used
successfully with a geothermal heat pump system. When
designing or retrofitting an existing hydronic heating
system, however, the water temperature produced by the
heat pump is a major consideration.
In general, heat pumps are not designed to produce water
above 130°F. The efficiency decreases as the temperature
difference (
loop) and the supply water (to the distribution system)
increases. Figure 1 illustrates the effect of source and load
temperatures on the system. The heating capacity of the heat
pump also decreases as the temperature difference increases.
When using the various types of hydronic heat distribution
systems, the temperature limits of the geothermal system
must be considered. In new construction, the distribution
system can easily be designed with the temperature limits in
mind. In retrofits, care must be taken to address the operating
temperature limits of the existing distribution system.
Figure 1: As the
Performance (COP) decreases. When the system produces
130°F water from a 30°F earth loop, the
the COP is approximately 2.5. If the system is producing
water at 90°F, the
3.8, an increase of over 50%.
ΔT) between the heat load (generally the earth
ΔT increases, the Coefficient of
ΔT is 100°F, and
ΔT is 60°F and the COP rises to about
10
8
6
COP
4
Baseboard Radiation
In existing systems, baseboard radiation is typically
designed to operate with 160° to 240°F water or steam.
Baseboard units are typically copper pipe with aluminum
fins along the length of the pipe, as shown in Figure 2. A
decorative cover is normally fitted over the fin tube.
The operation of a baseboard radiation system depends on
setting up a convection current in the room: air is warmed
by the fin tube, rises and is displaced by cool air.
The heating capacity of a baseboard system is a factor of
the area of copper tube and fins exposed to the air and
the temperature difference between the air and the fin
tube. The velocity and volume of water flowing through
the baseboard affects the temperature of the copper and
fins. Baseboard units are normally rated in heat output/
length of baseboard at a standard water temperature and
flow. Manufacturers can provide charts which will give the
capacities at temperatures and flows below the standard.
Figure 3 shows approximate heating capacities for fin tube
radiation using water from 100° to 130°F water.
Baseboards are available using two or three fin tubes tiered
above one another in the same cabinet. With the additional
surface area, the air can be heated enough to set up a
convection current with water temperatures as low as 110°
to 130°F (see Figure 3).
It is important to ensure that the heat output of the system is
adequate to meet the heat loss of the room or building at the
temperatures the geothermal system is capable of producing.
Baseboard radiation is limited to space heating. Cooling is
typically provided by a separate, forced air distribution system.
Figure 2: Baseboard radiators are typically constructed of
copper tube with closely spaced aluminum fins attached
to provide more surface area to dissipate heat. Some of
the factors affecting the amount of heat given off by fin
tube radiators are the water temperature, water velocity, air
temperature, and fin spacing and size.
/Zc[W\c[4W\a
2
0
0 20 40 60 80 100
Temperature Difference (°F)
3\QZ]ac`S
1]^^S` BcPS
4W\BcPS
16
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