Johnson Controls RH Series User 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
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

4
Model Nomenclature
4
RH SERIES ENGINEERING GUIDE
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.
RHSW 050 R 0 0 A C
5-7 8 9 10 11 12
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 Option1,3
0 –No Hot Water Generation, No IntelliStart
2 –Hot Water Generation, No IntelliStart
3 –No Hot Water Generation, IntelliStart
5 –Hot Water Generation, IntelliStart
Vintage
*–Factory Use Only
Future Option
SS –Standard
Load Coax2
C –Copper
N–Cupronickel
Source Coax
C –Copper
N –Cupronickel
Controls Option
A – Aurora™ Base Controls (ABC)
Rev.: 10 June 2016
C
13
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.
1-4
SS *
14-15 16

5
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
The Single Hydronic Series
Features
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
Full refrigerant suction
tube, heat exchanger, and
waterline insulation to prevent
condensation at low loop
temperatures
High efficiency copper or
cupronickel coaxial heat
exchangers
Captive FPT water connections
eliminate 'egg-shaping' backup
wrench
Zero ODP and low GWP
R-410A refrigerant
High efficiency scroll
compressors for improved
reliability
Compressor sound
blankets for reduced noise
Dual isolation compressor
mounts to reduce noise
and vibration Standard waterlines out the
front (field switchable to back
via control box)
Optional Hot Water
Generator available on
040-075
High efficiency copper coaxial
heat exchanger (vented
double walled available only
on 018 and 025 "heating only"
models)
Discharge Muffler Helps
quiet compressor gas
pulsations
RH SERIES ENGINEERING GUIDE

6
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 1⁄2in.
[12.7 mm] thick 1 1⁄2lb. [681 g] density, surface coated,
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 1⁄4oz. per year.
• 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.
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.
Single Hydronic Series cont.
RH SERIES ENGINEERING GUIDE

7
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.
Water-to-Refrigerant Heat Exchanger Coil
Large oversized coaxial refrigerant-
to-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.
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.
Inside The Single Hydronic Series
RH SERIES ENGINEERING GUIDE

8
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 applica-
tion, 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 cor-
rosion 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.
Material Copper 90/10 Cupronickel 316 Stainless Steel
pH Acidity/Alkalinity 7 - 9 7 - 9 7 - 9
Scaling Calcium and
Magnesium Carbonate
(Total Hardness)
less than 350 ppm
(Total Hardness)
less than 350 ppm
(Total Hardness)
less than 350 ppm
Corrosion
Hydrogen Sulfide Less than 0.5 ppm (rotten egg
smell appears at 0.5 ppm) 10 - 50 ppm Less than 1 ppm
Sulfates Less than 125 ppm Less than 125 ppm Less than 200 ppm
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 Fouling
(Biological Growth)
Iron, FE2+ (Ferrous)
Bacterial Iron Potential < 0.2 ppm < 0.2 ppm < 0.2 ppm
Iron Oxide Less than 1 ppm, above this
level deposition will occur
Less than 1 ppm, above this
level deposition will occur
Less than 1 ppm, above this
level deposition will occur
Erosion
Suspended Solids Less than 10 ppm and filtered
for max. of 600 micron size
Less than 10 ppm and filtered
for max. of 600 micron size
Less than 10 ppm and filtered
for max. of 600 micron size
Threshold Velocity
(Fresh Water) < 6 ft/sec < 6 ft/sec < 6 ft/sec
NOTES: Grains = ppm divided by 17
mg/L is equivalent to ppm
2/22/12
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
Water Quality
RH SERIES ENGINEERING GUIDE

9
The Aurora Base Control System
Aurora Control Features Description Aurora ‘Base’
Microprocessor Compressor Control Microprocessor control of compressor for timings with FP1, HP,
LP, Condensate, assignable Acc relay •
Base Hot Water Generator
Operation
Compressor Contactor powers Hot Water Generator Pump with
inline circuit breaker and thermostat limit. •
Base Loop Pump Control Compressor Contactor powers Loop Pump with inline circuit
breaker and no loop pump linking capability. •
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 congured as a
master for connecting to devices such as a communicating thermostat, expansion board, or other satellite devices. The second
channel is congured as a satellite for connecting the Aurora Interface Diagnostics T
ool (AID Tool).
Service Device Description Aurora ‘Base’
Aurora Interface and Diagnostics
(AID) Tool
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
version of AID is at least the same or greater than the ABC
software version.
For Service
(Ver. 1.xx or greater)
Add On Thermostats and Zoning Description Aurora ‘Base’
HydroStatCommunicating controller for one hydronic heat pump. Optional
HZO Non-communicating controller for up to four heat pumps. Optional
HZC Non-communicating controller for one hydronic heat pump Optional
RH SERIES ENGINEERING GUIDE

10
The Aurora Base Control System cont.
Aurora ‘Base’ Control
NOTE: Refer to the Aurora Base Control Application and
Troubleshooting Guideand 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/Conguration 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
by cycling the power. NOTE: Test mode will automatically
be exited after 30 minutes.
Reset Conguration Mode
The control is placed in reset conguration mode by
holding the push button switch SW1 for 50 to 60 seconds.
This will reset all conguration settings and the EEPROM
back to the factory default settings. LED3 (green) will turn
o when entering reset conguration 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 90seconds.
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 80second random start uponpower up.
RH SERIES ENGINEERING GUIDE

11
The Aurora Base Control System cont.
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 hard-
wired 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 self-
resetting 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.
RH SERIES ENGINEERING GUIDE

12
The Aurora Base Control System cont.
CC2
EH1
Factory
Fault
ALG
ALM
LS
ES
ACCc
Status
AURORA BASE
CONTROL™
RV – K1
CC2
CC – K2
CCHi – K3
Fan – K4
Alarm–K5
Acc – K6
ACCno
ACCnc
O/B
C
R
LO
G
Y1
Y2
W
DH
3A-Fuse
O/B
C
R
LO
G
Y1
Y2
W
DH
LO
G
HI
CCG
CC
FG
F
R
HP
HP
LP
FP2
FP2
FP1
REV
REV
CFM
PWM
ECMPWM
Factory
Factory Fan Connection
RR
CC
C
RS 485
EH2
C
EH1
C
CO
(+)
(-)
R
C
RS485 Exp Factory
Com1
Com2
Config
G
G
G
YR
SW1Test
FP1 – 15oF/30oF
JW2 -
Alarm
P11
P5
P2 P1
P8
P7
P9
P6
P3
SW2
P13
P4 FP2 – 15oF/30oF
RV – B/O
ACC – Dip 4
ACC – Dip 5
CC – Dual/Single
L – Pulse/Continuous
Reheat/Normal
Factory Use
FieldConnectionsFieldConnections
C
LP
FP1
F
CC
G
Y1
1
2
3
4
5
6
7
8
Off On
N/A
RS485 NET
LED3
LED2LED1
ABC Control Board Layout
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 Reset/ Remove
ABC Basic Faults
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
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.
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.
RH SERIES ENGINEERING GUIDE

13
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.
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
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:
• 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.
Application Notes
Supply Water
Return Water
Pumps
Water-to-water
Unit
Heater/
Rejector Water-to-water
Unit
Water-to-water
Unit Water-to-water Unit
Water-to-water
Unit
Water-to-water
Unit
Vertical - Closed Loop/Ground Source
RH SERIES ENGINEERING GUIDE

14
• 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 ground-
source 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.
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.
• 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.
Application Notes cont.
Surface Water - Closed Loop/Ground Source
Plate Heat Exchanger - Closed Loop/Ground Water
RH SERIES ENGINEERING GUIDE

15
Typical Application Piping
LOAD PUMP
HYDRONIC
LOAD
Source OUT
P/T PortsP/T Ports
Ball 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.
1-1/2 in.
FPT
Expansion
Tank
Air
Vent
Pressure
Gauge
30 psi
RELIEF VALVE
Air
Separator
FROM
HWG
TO
HWG
Back Flow Preventer /
Pressure Relief Valve
Source IN
5 Series
GEO
STORAGE
TANK
PUMP
HOT
(Piped in
series to
an electric
water heater)
COLD
DOMESTIC
Dip Tube
Ball Valve
Vent Valve/
P/T Port**
Application Notes cont.
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.
Hydronic Unit
RH SERIES ENGINEERING GUIDE

16
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 (ΔT) between the heat load (generally the earth
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 ΔT increases, the Coefficient of
Performance (COP) decreases. When the system produces
130°F water from a 30°F earth loop, the ΔT is 100°F, and
the COP is approximately 2.5. If the system is producing
water at 90°F, the ΔT is 60°F and the COP rises to about
3.8, an increase of over 50%. 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.
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.
Application Notes cont.
Temperature Difference (°F)
0 20 40 60 80 100
COP
2
4
6
8
10
0
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RH SERIES ENGINEERING GUIDE

17
Application Notes cont.
The heating capacity (Btuh/linear foot) of baseboard
radiators drop as the water temperature is reduced. The
heating capacity of most baseboard radiators is rated using
200°F water, 65°F air temperature. Listed in Figure 3 is the
range of heating capacities of baseboard radiators at the
standard temperatures and the range of capacities when
the temperatures are reduced to the operating range of
a heat pump system. Some of the factors that effect the
capacity of a radiator are:
• Size of the fins - range from 2.75 in. x 3 in. to 4 in. x 4 in.
• Fin spacing - 24 to 48 foot
• Diameter of copper tube - range from .75 in. to 2 in.
• Fin material - aluminum or steel
• Configuration and height of the enclosure
• Height unit is mounted from the floor
• Water flow through the radiator
Generally, the smaller fins with fewer fins/foot will have
lower heating capacity. Larger copper tube diameter and
aluminum fins will have a higher capacity. Higher water flow
will increase capacity. Adding a second fin tube to the same
enclosure will increase the capacity by 50 to 60%. Adding
two fin tubes will increase the capacity by 75 to 80%.
Cast Iron Radiation
Retrofit applications for hydronic/geothermal heat pump
systems are often required to work with existing cast iron
radiators or their replacements (see Figure 4). Typically,
cast iron radiator systems operate with water temperatures
of 125° to 160°F.
These temperatures are higher than geothermal water-
to-water heat pumps are capable of providing. Cast iron
radiators can work with geothermal systems, provided the
heat output of the radiators will meet the maximum heat
loss of the building at the lower temperatures.
If the insulation of the building has been upgraded since
the original installation, it is possible that the lower
temperatures will be able to meet the reduced heat loss of
the building.
Average
Water Temp.
Entering Air Temperatures
55°F 65°F 70°F
110
° F190-380 160-320 150-300
120°F
240-480 205-410 195-390
130
° F295-590 265-532 245-490
Figure 3: Heating output per linear foot
Radiant Floor Heating
Radiant floor heating has been the system of choice in
many parts of Europe for some time. Manufacturers have
developed tubing designed for installation in concrete
floors and raised wood floors.
Floor heating systems have several benefits in residential,
commercial and industrial heating applications. In a
building with a radiant floor heating system, the entire floor
acts as a heat source for the room. People feel comfortable
with lower air temperatures if their feet are warm. Typically
the space will feel comfortable with air temperatures as low
as 65°F. Since the heat loss of a building is directly related
to the temperature difference (ΔT) between the inside and
outside, a lower ΔT means the heat loss is lower.
Air temperatures in a room with a forced air heating system
tend to be warmer nearer to the ceiling than the floor (see
Figure 5). The hot air rises and creates a greater pressure
imbalance between the inside and outside. The infiltration
increases, resulting in a higher heat loss. Air temperatures
in a room with radiant floor heating tend to be warmer at
the floor than the ceiling, helping to cut down on infiltration
in the building. The energy savings in a building with
radiant floor heating can range from 10 to 20%.
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Figure 4: Baseboard System
Figure 5: Temperature Comparison
10° 10°
85°
95°
79°
68°
63° 81° 81° 81°
65° 65° 65°
60° 60° 60°
Forced Air System Radiant Floor Heat
95°
90°
74°
100° 59°
RH SERIES ENGINEERING GUIDE

18
A floor heat system can be designed to heat a building with
water temperatures as low as 90°F.
Figure 1 shows how a geothermal system operates more
efficiently with a lower ΔT between the source and
the load. With only a 60°F temperature difference, a
geothermal heat pump will operate at COPs over 4, about
20% higher than a forced air geothermal system in the
same installation.
Some of the factors affecting the heating capacity of a
floor heating system are as follows:
• The type of finish flooring
• The spacing of the pipe
• The water flow through the pipe
• The temperature of the supply water
• The floor material (wood, concrete or poured Gypcrete™)
• Insulation value under the floor
• The piping layout
The spacing of the pipe in residential applications can
vary from 4 in. to 12 in. If the spacing is too large, the
temperature of the floor can vary noticeably. In industrial
applications, variation in the floor temperature is not as
important, and the spacing is related directly to the heat
output required.
Radiant floor heating systems work well with geothermal
heat pump systems. For efficient operation, the system must
be designed with the lowest possible water temperatures.
There are some drawbacks with a radiant floor heating
system. Air conditioning is only possible by adding a
second system using forced air. This can add substantial
cost to an installation where air conditioning is also needed.
A separate air handling system is needed to clean the air or
to introduce fresh air.
Industrial buildings, especially those with high ceilings and
large overhead doors, have an advantage with a radiant
floor heating system. Heat is stored in the concrete floor,
and when a door is opened, the stored heat is immediately
released to the space. The larger the ΔT between the air in
the space and the floor, the quicker the floor releases its
heat to the space.
Maintenance garages benefit from radiant floor heating
systems. Cold vehicles brought into the garage are warmed
from underneath. The snow melts off the vehicle and dries
much more quickly than when heated from above.
Some pipe manufacturers include an oxygen diffusion
barrier in the pipe to prevent oxygen diffusion through the
pipe. Good system design and careful installation, however,
will eliminate virtually all of the problems encountered
with air in the system. Like earth loop design, it is important
to design the system to facilitate flushing the air initially
and ensuring that the flows can be balanced properly.
Fan Coil Units and Air Handlers
Fan coil units, air handlers, force flow units, etc. are all
basically a hot water radiator or coil (usually copper piping
with aluminum fins) with a fan or blower to move the
air over the coil (see Figure 6). The term “fan coil units”
typically applies to smaller units that are installed in the
zone or area in which heating (or cooling) is needed. They
are available in many different configurations, sizes and
capacities. Fan coil units are designed to be connected to
a ductwork system and can be used to replace a forced air
furnace. Other units are designed for use without ductwork
and are mounted in a suspended ceiling space with only
a grill showing in place of a ceiling tile. Some can be
mounted on a wall under a window, projecting 8 in. to 10
in. into the room or even flush to the wall surface, mounted
between wall studs. Some are available with or without
finished, decorative cabinets. For industrial applications,
inexpensive “unit heaters” are available, with only a coil and
an axial fan. Fan coil units and unit heaters are normally
available with air handling capacities of 200 to 2,000 cfm.
The term “air handler” normally applies to larger units,
mounted in mechanical rooms, mechanical crawl spaces
or rooftops. They typically have an air handling capacity
of over 2,000 cfm and are available for capacities of up to
50,000 cfm. Air handlers are typically built for a specific
installation and are available with many different types of
heating and cooling coils. They can include additional coils
for heating make-up air, dehumidification and exhaust air
heat recovery.
Fan coils and air handlers typically have one or two coils
and a blower. Air is heated by hot water circulated through
the hot water coil. Chilled water is circulated through the
coil if air conditioning is needed. Blowers can be provided
to fit various applications, with or without duct-work.
Unit heaters typically use axial fans in applications where
ductwork is not needed.
Fan coil units and air handlers are used in many different
applications. They have been used to heat buildings
using water temperatures as low as 90° to 100°F. New
systems can be designed to operate very efficiently with a
geothermal system.
Application Notes cont.
RH SERIES ENGINEERING GUIDE

19
Cooling with a Hydronic System
Cooling a building with an existing radiant hydronic heating
system can be a challenge. If baseboard, cast iron radiators
or a radiant floor heating system is cooled lower than the
dew point, condensation will form on the floor or drip off
the radiators.
There is generally minimal or no ductwork for ventilation
in existing buildings with radiant hydronic heat. Typically,
cooling is provided with separate units where it is needed.
This is often done using through-the-wall or window
air conditioners, ductless split air conditioning units, or
rooftop units.
A water-to-water heat pump system can provide water to
ducted or unducted fan coil units. The system can provide
chilled water to cool the building, as well as hot water for
the heating system when needed.
A limited amount of cooling can be done by circulating
chilled water through the piping in the floor. This can be
effective in buildings with high solar loads or lighting
loads, where much of the heat gain is radiant heat being
absorbed by the floor. Cooling fresh air used for ventilation
as it is brought into the building, using a chilled water coil,
can sometimes provide the additional cooling needed. Care
must be taken to avoid cooling the floor below the dew
point because condensation may form on the floor.
Buildings with fan coil units and air handlers can generally
be easily retrofitted for cooling. Often it is simply a matter
of adding a cooling coil to the existing air handlers and
fan coil units. Water-to-water heat pumps can provide hot
water for the heating coils as well as chilled water for the
air conditioning.
Application Notes cont.
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Figure 6: Fan Coils Controls
The control of a mechanical system determines how
it functions. For the building to work efficiently and
comfortably, the building owner or manager must
understand what the system is doing and how to control it.
As Figure 1 shows, the efficiency of a heat pump is a factor
of the difference in temperature between the source and
the load. The heat loss or heat gain of a building varies with
the weather and the use of the building. As the outdoor
temperature decreases, the heat loss of the building
increases. When the ventilation system is started up,
the heating or cooling loads increase. As the occupancy
increases, lighting or the solar gain increases, and the
cooling load increases. At times the building may require
virtually no heating or cooling.
With hydronic heating and cooling distribution equipment,
whether it is baseboard radiation, fan coil units or
radiant floor heating, the output of the equipment is
directly related to the temperature and velocity of the
water flowing through it. Baseboard radiation puts out
approximately 50% less heat with 110°F water than with
130°F water. The same is true with fan coil units and radiant
floor heating.
If a system is designed to meet the maximum heat loss of
a building with 130°F water, it follows that if the heat loss
is 50% lower when the outdoor temperature is higher and
the building has high internal gains because of lighting and
occupancy, the lower heat loss can be met with 110°F water.
This greatly increases the COP of the heat pumps.
The same control strategy is equally effective in cooling.
During peak loads, water chilled to 40°F may be needed;
at other times 55°F water will provide adequate cooling.
Significant increases in the EER can be achieved. Latent
loads must always be considered when using warmer water.
RH SERIES ENGINEERING GUIDE

20
Dimensional Data
2/15/16
B
C
A
D
L
E
I
K
M
RNSQP
T
O
U
V
Y
Z
X
W
F
GH
J
Model
Overall Cabinet Water Connections Electrical Knockouts
JKL
ABCDEFGH I 1/2 in.
cond
3/4 in.
cond
3/4 in.
cond
Depth Height Width
Load
Liquid
In
Load
Liquid
Out
Source
Liquid
In
Source
Liquid
Out
HWG In HWG
Out
Load
Water
FPT
Source
Water
FPT
HWG
Water
FPT
Low
Voltage
Ext
Pump
Power
Supply
018 in. 23.5 26.1 19.5 10.0 22.2 10.0 22.2 - - 1 in. 1 in. - 16.0 14.2 14.2
cm. 59.7 66.3 49.5 25.4 56.4 25.4 56.4 - - 25.4 mm 25.4 mm - 40.6 36.1 36.1
025 in. 23.5 26.1 19.5 10.0 22.2 10.0 22.2 - - 1 in. 1 in. - 16.0 14.2 14.2
cm. 59.7 66.3 49.5 25.4 56.4 25.4 56.4 - - 25.4 mm 25.4 mm - 40.6 36.1 36.1
040 in. 31.0 26.2 22.0 2.1 19.6 2.1 19.6 23.9 23.9 1 in. 1 in. 1/2 in. 17.1 14.8 17.1
cm. 78.7 66.5 55.9 5.3 49.8 5.3 49.8 60.7 60.7 25.4 mm 25.4 mm 12.7 mm 43.4 37.6 43.4
050 in. 31.0 26.2 22.0 2.2 20.6 2.2 20.6 23.9 23.9 1-1/4 in. 1-1/4 in. 1/2 in. 17.1 14.8 17.1
cm. 78.7 66.5 55.9 5.6 52.3 5.6 52.3 60.7 60.7 31.8 mm 31.8 mm 12.7 mm 43.4 37.6 43.4
060 &
075
in. 31.0 26.2 22.0 2.4 23.0 2.4 23.0 20.6 20.6 1-1/4 in. 1-1/4 in. 1/2 in. 17.1 14.8 17.1
cm. 78.7 66.5 55.9 6.1 58.4 6.1 58.4 52.3 52.3 31.8 mm 31.8 mm 12.7 mm 43.4 37.6 43.4
Model
Water Connections Electrical Knockouts
MNOPQR S T U VWX Y Z
Load
Liquid In
Load
Liquid
Out
Source
Liquid In
Source
Liquid
Out
HWG In HWG
Out
Power
Supply
Low
Voltage
Side
Power
Supply
Side
Power
Supply
Ext
Pump
Ext
Pump
Power
Supply
Power
Supply
018 in. 2.4 2.4 2.4 2.4 - - 3.5 2.9 14.9 2.6 2.1 1.8 2.9 4.1
cm. 6.1 6.1 6.1 6.1 - - 8.9 7.4 37.8 6.6 5.3 4.4 7.4 10.4
025 in. 2.4 2.4 2.4 2.4 - - 3.5 2.9 14.9 2.6 2.1 1.8 2.9 4.1
cm. 6.1 6.1 6.1 6.1 - - 8.9 7.4 37.8 6.6 5.3 4.4 7.4 10.4
040 in. 1.6 2.8 2.8 1.6 2.0 1.8 4.8 4.8 17.1 2.8 14.9 4.8 4.8 17.1
cm. 4.1 7.0 7.0 4.1 5.1 4.6 12.2 12.2 43.4 7.0 37.8 12.2 12.2 43.4
050 in. 1.8 3.6 3.6 1.8 2.1 1.8 4.8 4.8 17.1 2.8 14.9 4.8 4.8 17.1
cm. 4.6 9.1 9.1 4.6 5.3 4.6 12.2 12.2 43.4 7.1 37.8 12.2 12.2 43.4
060 &
075
in. 1.8 4.0 4.0 1.8 4.2 1.4 4.8 4.8 17.1 2.8 14.9 4.8 4.8 17.1
cm. 4.6 10.2 10.2 4.6 10.7 3.6 12.2 12.2 43.4 7.1 37.8 12.2 12.2 43.4
8/6/10
RH SERIES ENGINEERING GUIDE