Northern Heatpump RT-SE-033, RT-SE-020, RT-SE-026, RT-SE-040, RT-SE-052 Installation & Operating Instructions Manual

Two-Stage Split Geothermal Heat Pump

Installation & Operating Instructions

Application

 Retrofit existing forced air installations.
 Dual Heat – combine this geothermal unit and A-coil with stand-by gas or oil furnace.
 LMC (Load management control) ready.

Information

The air coil furnished with this product has been tested and
certified with this unit. To maintain the specification
performance and product certification, the air coil shipped with

this unit must be used.

This unit is NOT tax credit eligible when a coil other than the
furnished coil is used.

For proper performance, the CFM airflow required in the
specification table must be provided by the installed furnace
blower/air handler.

Since this product requires line sets and air coil installation, an
experienced and licensed refrigeration technician is required.

Domestic Water Heater, Desuperheater

Energy Star promotes the desuperheater and it is standard with this series. However, it only efficiently
produces hot water if the tank temperature is less than 115° F (46° C). Thus, for proper and efficient
application a hot water buffer tank is suggested, see page 17.

Note

The EZGEO control board has a configuration mode dial switch. This must be correctly set during
installation, see EZGEO Controller (HC112) and Field Setup sections.

Drawings:

EC001, HC112, NH501, NR501, NS501, XX029

DO NOT DESTROY THIS MANUAL. PLEASE READ CAREFULLY AND KEEP IN A SAFE

PLACE FOR FUTURE REFERENCE BY A SERVICE TECHNICIAN.

Model: (RT-SE*)

09/29/2010 NI501

Table of Contents

Introduction 1

Product Configurator (NC029) 2

Mechanical Specifications 3

Electrical Data 4

Product Dimensions 5

Installation Requirements 6

Mechanical Installation Overview 7

Mechanical Installation Source Water 9

Flushing and Filling Procedure 11

Desuperheater, Domestic Hot Water 16

Duct System/A-Coil 18

Mechanical Installation Refrigeration 19

Charging Procedure 21

Superheat and Subcooling 22

Electrical Hookup 25

EZGEO Controller 26

Temperature Sensors, Field Install 29

Gas Furnace Hookup – Mode D 30

Additional Hookup or Special Equipment Concerns 31

Field Setup or Programming 32

Operation Indicators 34

Power On, Start Up 35

Operational Tips 36

Troubleshooting 37

Accessories/Options 42

Drawings EC001

HC112
NH501
NR501
NS501
XX029

09/29/2010 NI501

Introduction

When used and controlled properly, geothermal heat pumps can save hundreds of dollars in heating and cooling
costs per year. Northern Heat Pump NorthStar Series geothermal heat pumps are designed to provide maximum
efficiency, comfort, and reliability. Solid and simple electric controls allow for low maintenance and built in
safety protection.

This is a pre-wired package for converting a new or existing oil or gas furnace into a dual heat system. This is a
complete package for both heating and air conditioning, utility load control, and compatible with DC drive

variable speed furnaces. There are no additional relays or option hardware needed for the outlined application.
The utility load control receiver properly switches the heating mode and properly controls the air conditioning

mode during summer load interrupt. The blower circuit and control is also designed for heating interrupt

(blower handled by gas furnace only) and continuous operating blower during cooling peak load interrupt.

Typically these controls and design features are only found in this product.

Moving and Storage

Units should be stored in original packaging in a clean dry area. Store and move units in normal upright
position. Do not stack units.

Initial Inspection

Be certain to inspect all cartons and crates as units are received before signing the freight bill. Verify that all
items received have no physical damage. Report any damages or shortages on the freight bill. The purchaser is
responsible for filing the necessary claims with the carrier. Concealed or hidden damages not discovered until
removing packaging must be reported to the carrier within 15 days of receipt.

Unit Location and Mounting

Locate the unit in an indoor area where the ambient temperature will remain above 45°F [8°C]. Northern Heat
Pump provides 4 removable panels for ease of servicing; front (2), right and left bottom. This unit is zero
clearance rated; however, allow enough room to remove panels for service and maintenance. Suggest setting

unit on a sound vibration pad, see accessories price sheet, R-PAD-2735-1-**. Water supply should not be hard

plumbed directly with copper pipe as this could transfer any vibration to living space.

Please read and understand conditions associated with proper installation, unauthorized changes, and POWER ON
procedures.

Warranty Statement

See the last page of this manual for detailed limited warranty coverage explanation.

Safety Considerations

WARNING

BEFORE PERFORMING SERVICE OR MAINTENANCE OPERATIONS ON A SYSTEM, TURN OFF
MAIN POWER SWITCHES TO THE INDOOR UNIT. IF APPLICABLE, TURN OFF THE ACCESSORY
HEATER POWER SWITCH. ELECTRICAL SHOCK COULD CAUSE PERSONAL INJURY.

Installing and servicing heating and air conditioning equipment can be hazardous due to system pressure and
electrical components. Only trained and qualified service personnel should install, repair or service heating and
air conditioning equipment. Untrained personnel can perform the basic maintenance functions of cleaning coils
and cleaning and replacing filters. All other operations should be performed by trained service personnel.
When working on heating and air conditioning equipment, observe precautions in the literature, tags and labels
attached to the unit and other safety precautions that may apply, such as the following safety measures:

 Follow all safety codes.
 Wear safety glasses and work gloves.
 Use a quenching cloth for brazing operations.
 Have a fire extinguisher available for all brazing operations.

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Northern Heat Pump Configurator

R T - S E - 0 5 2 - 1 - C X D X 1 - X X - U S

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17

Model Number Digits

RT-SE-052-1-CXDX1-XX-US

Geo Source (1)

Unit Type (2)

T = Two Stage

Unit Style (3)

S = Split

Refrigerant (4)

E = R-410A

Nominal BTU (5, 6, 7)

020 = 1.5-ton
026 = 2.0-ton
033 = 2.5-ton
040 = 3.0-ton
045 = 3.5-ton
052 = 4.0-ton
062 = 5.0-ton

Split System Coils

Country of Origin (16, 17)

US = United States

Auxiliary kW Option (14, 15)

XX = None

Vintage (13)

1

Miscellaneous Kits (12)

X = None

Desuperheater Option (11)

D = Desuperheater w/ Factory

Installed Pump

X = None

Configuration Option (10)

C = Split Air Coil
X = No Split Air Coil

Heat Exchanger Option (9)

C = Copper

Voltage Option (8)

1 = 208/230V, 1 Ph
2 = 208/230V, 3 Ph

R-AE-030-21-US

R = Geo

Always A

Refrigerant

E = R-410A

Coil Size

21 = 21”
24 = 24”

Coil Capacity

024 = 24k BTU (2-ton)
036 = 36k BTU (3-ton)
048 = 48k BTU (4-ton)
060 = 60k BTU (5-ton)

09/17/2010 NC029

Mechanical Specifications – R410A Two-Stage Compressor

MODEL

RT-SE-020

(1.5 ton)
Coax & Piping Water Volume – gal .43 .43 .65 .65 1.1 1.1
Internal Pressure Drop (feet) 6.2 6.2 4.2 5.5 6.2 8.0
Internal Pressure Drop (psi) 2.7 2.7 1.8 2.4 2.7 3.5
Source Temperature °F (min/max) 20°/120° 20°/120° 20°/120° 20°/120° 20°/120° 20°/120°
Nominal source differential* ° F (H/C) 3/10° 3/12° 8/11° 9/11° 6/11° 6/10°
Factory Charge R410A -(oz) * 40 46 46 64 96 96
Static Pressure – Nominal 0.3 0.3 0.3 0.3 0.3 0.3
Static Pressure – Design 0.5 0.5 0.5 0.5 0.5 0.5

Air Filter

Weight– Packaged (lbs) 420 440 460 480 503 530

*Shown as reference information only, see unit nameplate for the supplied factory charge for each specific unit.

Model Stage

Source

GPM

RT-SE-026 FL 7 35.49 900 39 4.52 29.70 900 32 4.24 24.47 900 26 3.82
RT-SE-026 PL 7 24.39 700 33 4.60 21.68 700 29 4.30 18.74 700 26 3.84

RT-SE-033 FL 8 41.36 940 42 4.04 36.30 950 36 3.95 27.65 950 28 3.49
RT-SE-033 PL 8 28.45 720 38 4.66 23.40 700 32 4.02 20.80 714 28 3.73

RT-SE-040 FL 10 52.00 1210 41 4.51 42.72 1205 34 4.27 33.19 1200 27 3.72
RT-SE-040 PL 10 37.47 1020 35 5.47 30.80 1000 30 4.72 27.28 1000 26 4.26

RT-SE-052 FL 13 68.18 1500 43 4.00 53.31 1500 36 3.72 44.93 1500 29 3.31
RT-SE-052 PL 13 47.09 1200 37 4.40 37.75 1200 30 3.72 33.75 1180 27 3.43

RT-SE-062 FL 15 81.87 1840 35 4.02 66.71 1840 35 4.02 53.35 1820 28 3.57
RT-SE-062 PL 15 63.45 1520 40 4.88 50.00 1470 32 4.11 45.40 1475 29 3.82

Model Stage

Source

GPM

RT-SE-026 FL 7 32.46 950 20 13.4 36.87 950 22 20.3 30.17 950 20 16.06
RT-SE-026 PL 7 24.35 750 20 14.5 28.00 750 21 22.0 22.66 750 22 19.2

RT-SE-033 FL 8 33.71 1000 20 14.2 38.87 1000 22 20.5 36.06 1000 21 15.9
RT-SE-033 PL 8 25.28 730 22 13.3 29.16 740 25 21.3 27.05 750 24 18.0

RT-SE-040 FL 10 42.28 1260 22 13.9 47.48 1260 23 20.0 44.68 1260 22 16.1
RT-SE-040 PL 10 31.69 1055 21 17.0 35.55 1055 22 27.1 34.92 1060 21 23.1

RT-SE-052 FL 13 55.75 1600 22 12.9 64.95 1600 23 19.1 58.00 1600 22 15.1
RT-SE-052 PL 13 41.70 1300 20 14.8 48.28 1275 22 24.4 46.63 1275 22 21.4

RT-SE-062 FL 15 71.21 1970 21 14.2 76.65 1970 23 18.7 72.60 1970 23 15.6
RT-SE-062 PL 15 54.06 1600 22 16.2 57.50 1630 21 23.1 60.34 1670 22 22.1

1. Capacities are based on temperatures shown in heading, source is left group, return air is right group.

2. Stated Btu/h are the ISO 13256-1 formula adjusted, actual HP supply energy delivered is 2% greater.

3. Temp rise is based on sensible only.

4. All ratings based upon operation at lower voltage of dual voltage rated models.

5. Ground Loop Heat Pump ratings based on 15% antifreeze solution.

HEATING – ISO 13256-1 SPECIFICATION – ENERGY STAR

Capacity

Btu/h

COOLING – ISO 13256-1 SPECIFICATION – ENERGY STAR

Capacity

Btu/h

7/8 X 21 7/8

X 27 1/2

WLHP – Water Loop GWHP – Ground Water GLHP – Ground Loop

68° F 68° F 50° F 68° F 32° F/41° F 68° F

Blower

CFM

WLHP – Water Loop GWHP – Ground Water GLHP – Ground Loop

86° F 80.6° F 59° F 80.6° F 77° F/68° F 80.6° F

Blower

CFM

Temp

Rise

Temp

Drop

RT-SE-026

(2 ton)

7/8 X 21 7/8

X 27 1/2

COP

EER

Capacity

Btu/h

Capacity

Btu/h

RT-SE-033

(2.5 ton)

7/8 X 21 7/8

X 27 1/2

Blower

CFM

Blower

CFM

RT-SE-040

(3 ton)

7/8 X 28 7/8

X 27 1/2

Temp

Temp

Drop

Rise

COP

EER

RT-SE-052

7/8 X 27 1/2

Capacity

Btu/h

Capacity

Btu/h

(4 ton)

X 37 7/8

RT-SE-062

7/8 X 27 1/2

Blower

CFM

Blower

CFM

(5 ton)

X 37 7/8

Temp

Rise

Temp

Drop

COP

EER

09/29/2010 3 NI501

Electrical Data – Single Phase

Desup.

Pump

Model

Voltage Compressor

(60 Hz) RLA LRA FLA FLA FLA Ampac.

020 208/230-1 10.3 52 .15 4.4 14.9 17.4 30
026 208/230-1 14.1 70 .15 4.4 18.7 22.2 40
033 208/230-1 16.7 82 .15 4.4 21.3 25.4 50
040 208/230-1 16.7 96 .15 4.4 21.3 25.4 50
052 208/230-1 25.6 118 .15 4.4 30.2 36.6 60
062 208/230-1 27.2 150 .15 4.4 31.8 38.6 60

Loop

Pump

(Ext)

Total Min.

Max.

Fuse/

HACR

Electrical Data – Three-Phase

Desup.

Pump

Model

Voltage Compressor

(60 Hz) RLA LRA FLA FLA FLA Ampac.

020 200/230-3 7.1 59 .15 4.4 11.7 13.4 30
033 200/230-3 11.2 58 .15 4.4 15.8 18.6 40
040 200/230-3 13.5 88 .15 4.4 18.1 21.4 40
052 200/230-3 17.6 123 .15 4.4 22.2 26.6 50

Loop

Pump

(Ext)

Total Min.

Max.

Fuse/

HACR

09/29/2010 4 NI501

Product Dimensions

09/29/2010 5 NI501

Installation Requirements

1. All installation work must be performed by trained, qualified contractors or technicians. Northern Heat

Pump, sponsors installation and service schools to assist the installer. Visit our Website at

www.electromn.com

WARNING

ALL ELECTRICAL WIRING MUST BE IN ACCORDANCE WITH NATIONAL ELECTRIC CODE
AND LOCAL ELECTRIC CODES, ORDINANCES, AND REGULATIONS.

WARNING

OBSERVE ELECTRIC POLARITY AND WIRING COLORS. FAILURE TO OBSERVE COULD
CAUSE ELECTRIC SHOCK AND/OR DAMAGE TO THE EQUIPMENT.

CAUTION

This unit can only be used for its intended design as described in this manual. Any internal
wiring changes, modifications to the circuit board, modifications or bypass of any controls, or
installation practices not according to the details of this manual will void the product warranty,
the safety certification label, and manufacturer product liability. Northern Heat Pump, cannot
be held responsible for field modifications, incorrect installations, and conditions which may
bypass or compromise the built-in safety features and controls.

2. If this is a Dual Heat system, this product relates only to the addition to the furnace ducting system external

to the gas or oil force air furnace. The owner/ installer assumes all responsibility and/or liability associated
with any needed installation of the gas/oil furnace, fuel system, flue, chimney, etc. Any instructions or
comments made within this manual (or factory phone assistance) relating to the gas/oil furnace are provided
as comments of assistance and “helps” only.

for upcoming service schools.

CAUTION

This unit shall not be operated (either heating section or blower) until the interior of the
structure is completed and cleaned. This also means all duct work must be complete with filter,
etc. Manufacturer’s warranty is void if this unit is operated during structure construction.

CAUTION

Hazards or unsafe practices could result in property damage, product damage, severe personal
injury and/or death.

3. All removed or discharged refrigerant must be recovered. Local and federal statutes are to be observed.

Should a compressor need replacing, the compressor oil is to remain with the compressor. Refrigerant lines
on the compressor must be sealed.

4. Remember, safety is the installer’s responsibility and the installer must know this product well enough to

instruct the end user on its safe use.

At Northern Heat Pump, the safety of the installer and the end user is of highest priority. Remember, safety
is the installer’s responsibility and the installer must know this product well enough to instruct the end user
on its safe use. Professional installers should be trained and experienced in the areas of handling electrical
components, sheet metal products, and material handling processes.

09/29/2010 6 NI501

Mechanical Installation Overview

This NHP Series unit cannot produce
furnace system. The following items should be carefully considered and properly followed for all installations:

Examination of the existing forced air furnace – Prior to starting this installation or furnace modification,

examine the total furnace system and make necessary comments or recommendations to the homeowner.
Remember, if a marginal condition exists within the existing forced air system, the installation of a geothermal
heat pump will not cure PRE-EXISTING conditions. Consider such items as proper fossil fuel ignition, is the
furnace cycling on hi-limit, filter, adequate cold air return, adequate supply duct and room register (1 register
per 100 CFM) etc.

Heating capacity – Size the geothermal heat pump according to the normal heating requirements as the building

exists today
oversize the geothermal heat pump.

Supply plenum – Carefully examine all sides of the plenum. The coil must be installed on the supply side of

the fossil fuel furnace. Verify all transitions have angles less than 30, the coil is centered within the plenum,
and there are no odd shaped angles or odd shaped transitions within the plenum.

Other plenum equipment – Auxiliary equipment such as humidifiers, zone plenum dampers, etc., located

within the plenum which may cause a non-uniform airflow issues may have to be removed if they cause to great
reduction to system airflow. Zone dampers within the trunk line at least 12" (30cm) from the coil typically are
no problem. When horizontal zone dampers are involved, perform all check-out functions with smallest zone
open first.

Insufficient cold air return capacity – Installation experience indicates this is a major concern. In fact, it

could represent a problem in as many as 60% of the installations, especially if there is a requirement to increase
airflow with the existing blower and the existing cold air return capacity is already undersized or restricted.
Check the static pressure within the return cabinet or the suction at the filter cabinet door. Do not assume
because there is a register on the wall, the hole behind the register or the passageways are equal to this register.
Sharp offsets and transitions in the cold air return system often cause severe restrictions. Expect to add
additional registers or a relief register in the main cold air return duct.

Blower CFM capacity – The furnace forced air system must have an airflow capacity larger than the minimum
requirement on the NHP Series specification sheet (see unit nameplate and/or Mechanical Specifications on
page 3). It is near impossible to correctly measure CFM airflow in an existing residential installation.

Experience and rule of thumb indicators will have to be followed to determine the existing furnace CFM
capacity. The following may be helpful:

. Do not necessarily match to the existing furnace nameplate because it may be oversized. Do not

Comment – zone dampers cause back pressure on the blower and overall reduced airflow. Reduced
airflow can cause the geothermal unit to perform poorly or in some cases cause icing or freeze ups in the
geo loop or air coil.

a. Existing furnace nameplate

the systems static pressure. What changes have been made to the heating system since
installation?

b. Blower motor size

2 ton unit - 1/3 HP or larger
3 ton unit - 1/2 HP or larger
4 ton unit - 3/4 HP or larger
5 ton unit - 1 HP or larger

c. Observe/examine airflow ducting system and design

industry equivalent duct capacity airflow charts and determine if the system is capable of
delivering the CFM required on the nameplate. Especially check the number of registers and

airflow and cannot correct airflow problems inherent within the existing

- Typically represents a high or optimistic rating and is a function of

- Used only as a minimal guide.

- Use duct sizing table (ECØØ1), or

09/29/2010 7 NI501

p

the number of “6 inch rounds”. The same would apply to cold air return duct capacity.

d. Calculated CFM

- By measuring the temperature rise across the existing furnace, the CFM can
be approximated. The accuracy of this formula will depend upon the estimated or determined
Btu output (actual heat energy across the furnace, not nameplate input).

CFM =

Btuh (output)

Temperature Rise x 1.08

Closed Loop Applications – Closed loop system re-circulates the same water/antifreeze solution through a
closed system of underground high-density polyethylene pipe. As the solution passes
through the pipe it collects heat (in the heating mode) that is being

Horizontal Closed Loop

transferred from the relatively warm surrounding soil through the pipe
and into the relatively cold solution. The solution is circulated back to
the heat pump that extracts its heat and then returns to the ground to
absorb more heat from the earth. Earth loops must be sized properly for
each particular geographic area and individual capacity requirements.

The NHP Series heat pumps are designed to
operate on either vertical or horizontal closed loop applications. (Figures 1 & 2)
Vertical loops are typically installed with a well drilling rig up to 200 feet (61
meters) deep or more. Horizontal systems are typically installed with excavating

Figure 1

Vertical Closed Loo

or trenching equipment approximately six to
eight feet deep, depending on geographic
location and length of pipe used.

Lake or Pond Loops – Closed loop systems may also be used in lakes or
rivers to supply a heat source to the heat pump. Typically a loop consisting
of geothermal pipe can be designed and placed in an area not much deeper
than 15ft (4.5 meters) with some water currents present. In any lake or
pond, municipal and area codes must be observed in regards to a lake or
pond loop. The use of an environmentally friendly loop fluid like ethanol
should be considered should damage ever occur to the loop. Consult an IGSHPA

Figure 2

or CGC certified installer for proper lake or pond loop design.

09/29/2010 8 NI501

Mechanical Installation Source Water

WARNING

LOOP DESIGN IS EXTREMELY IMPORTANT FOR PROPER HEAT PUMP OPERATION.
INCORRECT LOOP DESIGN WILL REDUCE HEAT PUMP EFFICIENCY, CAUSE POOR
PERFORMANCE OR MAY RENDER THE SYSTEM UNUSABLE. CONTACT AN IGSHPA OR
CGC CERTIFIED GEOTHERMAL LOOP CONTRACTOR FOR PROPER INSTALLATIONS.

Water Connections General

The following pages outline typical piping arrangements for the most common source water connection options,

as well as flushing and filling procedures and antifreeze requirements for closed loop systems. Do not connect

copper piping directly to the source water connection points on this unit. A section of flexible piping is
recommended to reduce and isolate vibrations transmitting from the compressor into other parts of the system.

Once closed loops are completed, they must be pressure tested to at least 60 PSI to insure integrity. Once
pressure is tested, loop must be purged of all foreign debris and filled with fluid. All air must be removed at this
time by flushing the system. (Table 2) shows approximate fluid volumes.

Pressure/Temperature (P/T) plugs – Should be installed in the adaptor elbow on the entering

and leaving water line of the heat pump on a closed system. (Figure 3) A thermometer can be
inserted into the P/T ports to check entering and leaving water temperatures. A pressure gauge
can also be inserted into these P/T ports to determine the pressure differential between the
entering and leaving water. This pressure differential can then be compared to the engineering
specifications data to determine the flow rate of the system.

Loop Pump Selection – Select a loop circulation pump based upon the GPM required and total system pressure

drop. See specification, page 3. Geo heat pump Btu/h capacity and efficiency are directly related to the GPM

flow though the unit.

Vibration pad – suggest setting the unit on a sound vibration pad, available from most distributors or

accessories price sheet – R-PAD-2735-1-**.

Water quality – models with standard copper heat exchanger coils require the installer to evaluate water quality

and meet minimum water properties.

 pH/calcium hardness pH < 7.5 and Ca harness < 100 PPM
 Iron fouling < 0.2 PPM (Ferrous)

< 0.5 PPM of oxygen

 Hydrogen sulfide (H

S) < 0.5 PPM

2

 Chloride levels < 20 PPM
 Erosion/clogging < 10 PPM, particles
 Filter, if required < 800 micron size

P/T Adapter

Figure 3

09/29/2010 9 NI501

Figure 4 – Pressurized Closed Loop with Flow Center – Typical piping arrangement.

Figure 5 – Non-Pressurized Closed Loop with Flow Center – Typical piping diagram.

09/29/2010 10 NI501

p

eat Pump

p

p

Flushing and Filling the System Using 3-Way Valves

Step 1

Use water and a high volume head circulator pump to flush air and debris and to fill the loop system.

 Refer to recommendations provided by IGSHPA or CGC when choosing a pump for the flushing

process.

 It is recommended that pump suction be from the bottom of a large volume container. Use a suction

Step 2

Pump water into the system by connecting the pump discharge hose to one (not both) of the 1.00” NPT water
connections located on the sides of the module.
Connect a return hose to the opposite side of the module to discharge debris and air as water is added to the
loop.

Step 3

Rotate the module valves as shown in step 3 diagram:

Step 4

Start the pump. Add anti-freeze and water to the container as needed so that no air enters the system. This will
push any air out of the loop. If flushing assembly is equipped with valves to reverse flow direction, do so
occasionally to help remove trapped air. When bubbles cease in the return hose container, the earth loop has
been completely flushed.

Step 5

Flush the heat pump. To do so, simply rotate the valves as
shown in step 5 diagram while the pump is running. Flush
the heat pump using the same procedure as used to flush the
earth loop.

Pressurizing the System (does not apply to Figure 5)
Step 6

After flushing and filling the system, rotate the module valve
discharging into the flush container as shown in step 6A
diagram to pressurize the loop. Then turn the valves as in
step 6B.

Step 7

Turn off the flush cart pump. The system should remain
pressurized. Release excess pressure by rotating either
module valve to allow a small amount of water to pass
through and out of the system and into the container. Some
initial loss of pressure can be expected and is due to the
expansion of the earth loop pipe under pressure. The pressure
will stabilize if the system has no leaks.

Step 8

Flushing, filling and pressurization should be complete. Start
the loop pump module circulators.

Step 9

Troubleshoot. If for some reason the circulators are not
operating, power off and diagnose the problem.

Step 10

09/29/2010 11 NI501

line strainer to prevent debris discharged into the container from being recycled to the system.

Step 3

From
Flush
Cart

Step 5

From
Flush
Cart

To Heat Pump

Step 6A

From
Flush
Cart

To Heat Pump

From Heat Pum

Pressurize Loo

From Heat Pum

To H

To
Flush
Cart

To
Flush
Cart

Using a single water pressure gauge, measure the pressure drop at the pressure/temperature plugs across the heat
pump heat exchanger. Compare the measurement with the flow versus the pressure drop table (Table#3) and
determine the actual flow rate. If the flow rate is low, recheck the selection of the loop pump module model for
sufficient capacity. If the model is correct, there is likely trapped air or a restriction in the flow circuit.
System pressure should increase rapidly as the flush pump works to force more water into the system.
Additional flushing of the loop is needed if the water level in the loop falls. This shows that there is air in the
system. System operating pressures should be between 10 to 40 PSI.

Antifreeze

DO NOT mix more than 25% propylene glycol with water to achieve a lower than 15°F [-9°C] freeze

protection. (See Table 3) A more concentrated mixture cannot be pumped through the earth loop at low
temperatures. Lack of antifreeze will cause unit shutdown problems during cold weather operation (longest unit
run time) when the loop temperatures fall below the freeze protection of the antifreeze. Flow rate requirements
for closed loop solutions are higher than open loop systems because water temperatures supplied to the heat

pump are generally lower. Typically 2.0 to 3.0 gallons per minute (GPM) per ton are required for proper

operation of the heat pump and the earth coupled heat exchanger.

Table 2 – Approximate Fluid Volume (gal)

per 100ft

Pipe Size Volume

¾” IPS SDR 11 2.8

1” IPS SDR 11 4.5

Polyethylene

Rubber Hose 1” 3.9

Copper

1-1/4” IPS SDR 11 8.0

1-1/2” IPS SDR 11 10.9

2” IPS SDR 11 18.0

1” 4.1

1.25” 6.4

1.5” 9.2

Table 3 – Antifreeze Percentages by Volume*

Minimum Temperature for Freeze Protection

10°F 16°F 17°F 21°F 25°F

Type -12°C -9°C -8°C -6°C -4°C

Methanol 25% 21% 18% 16% 10%

Propylene

38% 30% 25% 22% 15%

Glycol

Ethanol 22% 20% 18% 14% 10%

*Reference information only, see product manufacturer

specification for percentage.

WARNING

DO NOT USE CALCIUM AS ANTI-FREEZE. FOLLOW CGC/IGSHPA RECOMMENDATIONS

FOR THE APPROPRIATE TYPE AND AMOUNT OF ANTI-FREEZE.

WARNING

PREVENTING FREEZE-UP IS INSTALLER/USER RESPONSIBILITY. LEAKING HEAT
EXCHANGER OR PIPING (EXTERNAL OR INTERNAL WITHIN THE REFRIGERANT/

COMPRESSOR) ARE NOT COVERED BY WARRANTY.

09/29/2010 12 NI501

Open Loop Well to Well – An open system gets its name from the open discharge of water after it has been

used by the heat pump. A well must be available that can supply all of the water requirements of the heat pump
along with any other water requirements drawing off that same well. The well must be capable of supplying the
heat pumps required flow rated for up to 24 hours per day for the coldest winter day.

Figure 6 shows the necessary components for water piping of an open system. First a bladder type pressure tank
with a “draw down” of at least 1-1/2 to 2 times the well pump capacity must be installed on the supply side of
the heat pump to prevent short cycling the well pump. Shut off valves and boiler drains on the entering and
leaving water lines are necessary for future maintenance. A screen strainer is placed on the supply line with a
mesh size of 40 to 60 and enough surface area to allow for particle buildup between cleanings. Pressure
temperature (P/T) plugs are placed in the supply and discharge lines so that thermometers or pressure gauges can
be inserted into the water stream. On the well water discharge side of the heat pump a flow control/shut off
valve must be mounted to regulate the maximum water flow through the unit. Remove handle to prevent
accidental change of flow.

A solenoid valve is then installed and wired to TB C & Y terminal on the heat pump. (Refer to NS501) This
valve will open when the unit is running and close when the unit stops. A visual flow meter is then installed to
allow visual inspection of the flow requirements. The flow meter can also be useful in determining when
maintenance is required. Schedule 40 PVC piping, copper tubing, polyethylene or rubber hose can be used for
supply and discharge water lines. Limit rubber hose to 10 ft. (3 meters) to prevent excessive pressure drop.
Make sure line sizes are large enough to supply the required flow with a reasonable pressure drop (generally

1.00” diameter). Water discharge is generally made to a drain field, stream, pond, surface discharge, tile line, or
storm sewer.

CAUTION

Using a drain field requires soil conditions and adequate sizing to assure rapid percolation or
the required flow rates will not be achieved. Consult local codes and ordinances to assure
compliance. Do not discharge water to a septic system. The heat pump should never be
operated with flow rates (GPM) less than specified. Operation of the unit with less than
required flow rate or no flow may result in freezing water in the water to refrigerant heat
exchanger. This will cause the unit to shut down on low-pressure lockout. If the unit locks
out, verify that the unit has the required flow and reset the unit by shutting off power to the unit
for one minute. Do not continually reset the unit; if the unit locks out more than once call your
service professional. Continued reset of the unit can freeze water inside the water coil to the
point of rupturing the water coil (no warranty for frozen coils).

09/29/2010 13 NI501

Figure 6: Open Loop Well to Well – Typical piping diagram.

Open Loop Freeze Protection Switch – Heat pump installations on open loop systems, using a non-antifreeze

protected water source during the heating mode require the use of a water coil freeze protection switch. If the
water supply to the heat pump is interrupted for any reason, continued operation of the compressor will cause
the water remaining in the water-to-refrigerant heat exchanger to freeze and rupture. The freeze protection
switch will shut the unit down before freezing can occur and protect the heat pump against flow loss and
damage.

Option – 39° F (4° C) pipe clamp-on, part number 6047. Connect in series with low limit.

Water Coil Maintenance – Water quality is a major concern for open systems. Problems can occur from

scaling, particle buildup, suspended solids, corrosion, pH levels outside the 7-9 ranges, or biological growth. If

poor water quality is known to exist in your area a cupronickel water coil may be required when ordering the

system, or installing a closed loop system may be the best alternative. Water coil cleaning on an open loop

system may be necessary on a regular basis.

09/29/2010 14 NI501

Depending on the specific water quality issue, the water coil can be cleaned by the following methods:

Chlorine Cleaning (Bacterial Growth)

1. Turn thermostat to “Off” position.

2. Connect a circulating pump to hose bibs on entering water and leaving waterside of heat exchanger.

3. Using a five-gallon pail of water add chlorine bleach mixture. The chlorine should be strong enough to

kill the bacteria. Suggested initial mixture is 1 part chlorine bleach to 4 parts water.

4. Close shut off valves upstream and downstream of heat exchanger.

5. Open hose bibs to allow circulation of bleach solution.

6. Start pump and circulate solution through heat exchanger for 15 minutes to one hour. Solution should

change color to indicate the chlorine is killing the bacteria and removing it from the heat exchanger.

7. Flush used solution down the drain by adding fresh water supply. Flush until leaving water is clear.

8. Repeat procedure until solution runs clear through the chlorine circulation process.

9. Flush entire heat pump system with water. This procedure can be repeated annually, semiannually, or

as often as it takes to keep bacteria out of the heat exchanger, or when bacteria appears in a visual flow
meter to the point the flow cannot be read.

Muriatic Acid Cleaning

Difficult Scaling and Particle Buildup Problems
Consult installer due to dangerous nature of acids.
Iron out solutions and de-scaling products are also useful.

09/29/2010 15 NI501

Desuperheater, Domestic Hot Water

General

All NHP Series units are equipped with a desuperheater and an integrated circulating pump (can be a price
deduct) that can provide Supplemental Domestic hot Water (SDW). This is done by stripping heat from the
superheated gas leaving the compressor.

Fuses – 3-amp fuses are installed in series with the desuperheater pump. The fuses are located in the line

voltage control box, upper right. Remove the fuses (turn 230 power source off) to disable the pump whenever
the system is not in operation.

General Plumbing and Installation Suggestions

1. Insulated ½” copper piping should be used from the hot water tank to the desuperheater connections on

the left side of the unit. The copper tubing should be straight to maintain good water velocity and
prevent pockets from forming at the pump inlet.

CAUTION

Due to high water temperatures generated by the desuperheater, pex or poly pipe may rupture if
coupled directly to heat pump outlet.

2. Shut off valves should also be used to service the desuperheater pump without draining the entire hot

water tank. Note: Always be sure these valves are open when pump is running.

3. Pump problems develop by running the pump dry or with air in the system. All air must be purged from

the desuperheater plumbing before the pump is engaged.

4. To purge air from the lines, loosen the desuperheater pump from its housing by turning the brass collar.

Let water drip out of the housing until flow is established and re-tighten the brass collar.

5. Never operate the system without the high temperature switch (normally factory installed) otherwise

tank temperatures could become dangerously high.

6. Poor water quality may restrict the effectiveness of using the desuperheater pump and will not allow the

pump to circulate.

7. Desuperheater maintenance includes periodically opening the drain on the hot water tank to remove any

deposits. Hard water may cause scale buildup in the desuperheater coil reducing its effectiveness.

8. The temperature difference between the water entering and leaving the desuperheater should be 5°F to

15°F. The water flow should be approximately 0.4 GPM per ton of nominal cooling.

9. Northern Heat Pump strongly suggests a water heater buffer tank, Figure 7, for the maximum efficiency

from the provided desuperheater module. The Figure 7A single tank plumbing and application is shown
for information only.

There are a number of ways the desuperheater/pump can be plumbed with and into the building/household water

heater tank. However, many common methods used are not very effective because they simply circulate

already heated water from the water heater tank through the desuperheater. The heat pump desuperheater cannot
effectively produce hot water energy if the temperature of the water entering the desuperheater is close to or
beyond the compressor gas capability to transfer energy into this circulated water – typically 110° F (46° C) to
130° F (54° C).

 Example – if the water heater electric element thermostat is set at 140° F (60° C), it will maintain

the tank at 140° F (60° C). There is no point in circulating 140° F (60° C) water through the
desuperheater because it is picking up very little or no energy from the compressor hot gas.

 In fact, the energy flow may even be negative if the Geo HP loop temperature is too low, it is

possible for a single tank hot water heater to actually flow energy into the Geo HP system with a

negative effect of energy efficiency.

09/29/2010 16 NI501

Figure 7 – Desuperheater Piping, Buffer Tank

This is the most effective and efficient arrangement
and the recommended installation. The buffer tank
need not be as big as the standard water heater; 40­gallon size can be very effective. With this two
tank system the desuperheater will always act as a

city/well water pre-heater and the standard water

heater (electric elements or gas) only requires
tempering energy which is a very small percentage
of domestic water heater energy required.

Figure 7A – Desuperheater, Single Tank Concept

Draw water from the bottom drain and returning it to the cold
water supply line. This method requires a check valve in the
cold water supply to prevent water from flowing into the
building or household cold water supply. A spring-type check
valve with a pressure rating of 1/2 PSI or less is recommended.

Inspect the dip tube in the water heater cold inlet for a check
valve. If a check valve is present it must be removed or damage
to the desuperheater circulator will occur.

Before restoring electrical supply to the water heater, adjust the
temperature setting on the tank.

 On tanks with both upper and lower elements, the

lower element should be turned down to the lowest
setting, approximately 100° F (38° C). The upper
element should be adjusted to 120° F (49° C) to
130° F (54° C). Depending upon the specific needs
of the customer, you may want to adjust the upper
element differently.

 On tanks with a single element, lower the

thermostat setting to 120° F (49° C).

CAUTION

Do not run desuperheater pump without supply from water heater. This will damage the pump.

09/29/2010 17 NI501

Duct System

An air filter must always be installed upstream of the air coil on the return air side of the air handler or furnace.
If there is limited access to the filter rack for normal maintenance, it is suggested that a return air filter grill be
installed. Be sure that the return duct is properly installed and free of leaks to prevent dirt and debris from
bypassing the filter and plugging the air coil.

In applications using galvanized metal ductwork, a flexible duct connector is recommended on both the supply
and return air plenums to minimize vibration from the blower. To maximize sound attenuation of the unit
blower, the supply and return plenums should include an internal duct liner of 1-inch thick glass fiber or be
constructed of ductboard. Insulation is usually not installed in the supply branch ducts. Ducts in unconditioned
areas should be wrapped with a minimum of 1-inch (25mm) duct insulation. Application of the unit to
uninsulated ductwork in an unconditioned space is not recommended as the unit’s performance will be adversely
affected. If the air handler is connected to existing ductwork, a previous check should have been made to assure
that the duct system has the capacity to handle the air required for the unit application. If ducting is too small,
as in replacement of heating only systems, larger ductwork should be installed. All existing ductwork should be
checked for leaks and repairs made accordingly. The duct system and diffusers should be sized to handle the
design airflow quietly. If air noise or excessive airflow is a problem, the blower speed can be changed to a
lower speed to reduce airflow. This will reduce the performance of the unit slightly in heating; however, it will
increase the temperature rise across the air coil. Airflow must still meet minimum requirements.

Air Coil Installation

This unit is furnished with the air coil matched to the heat pump system and compressor. To maintain the

product ratings, certification, etc. the furnished coil must be used.

Gas or Oil Furnace – Normally as required by the furnace manufacturer’s warranty, the refrigerant coil must be

in the supply or discharge plenum. It is recognized the furnished coil may be large and may present some
physical plenum issues, but it is matched to the size of the heat pump and thus this coil must be accommodated
within the forced air ducting system.

ST Duct Sensor – See page 29 for details relating to installing ST sensor above coil.

Airflow (CFM) – As listed on the unit nameplate and the page 3 specification table the minimum CFM must

flow through this coil. This is a function of the installer discerning the overall ducting system sizing/quality, the

furnace blower size/motor, furnace restrictions, return air restrictions, air filter, etc. This is not simply a
function of looking at the furnace nameplate. Proper CFM must be assured and guaranteed by the installer.

As the plenum is fabricated or rebuilt, all transitions must have angles of less than 30°, the coil must be centered
within the plenum, and there should not be any odd shaped angles or odd shaped transitions within the plenum.

09/29/2010 18 NI501

Mechanical Installation Refrigeration

Overview

The NHP Series split unit includes pre-charged R-410A, with the filter drier factory installed in the unit. The

charge will have to be fine tuned based upon line set length and system performance. Line set lengths of over

25ft (7.6 meters) are not recommended due to performance loss and potential oil return issues.

Forced Air Coil – The refrigerant coil supplied with this product model number must be used for this

installation. The nameplate and specification table ratings only apply when using the furnished air coil.

 Do not use existing or older A-coils because they probably are not designed for R-410A, may be

contaminated from other refrigerants, may not be large enough, and may not have the correct TXV
metering valve.

 Realizing the furnished coil is large, provisions and plenum arrangements must be made to

accommodate this coil. This is necessary again for proper Geo HP performance and meeting
specification requirements, Energy Star, ARI, etc.

 Airflow (minimum CFM) is also a key requirement for proper performance and rating, see previous

section.

Line Set Information – Factory charge is set to include enough refrigerant for 10ft (3 meters) of line set and the

forced air coil. If a line set of more than 10ft is used, additional R-410A refrigerant is required to be added to the
system. Added amount of refrigerant needed is based upon 0.5oz per ft for 3/8” and 1.0oz per ft for 1/2" liquid
lines.

Tube diameters and lengths for the line set are determined using the table on the following page. The suction
lines must be insulated. When handling the line set, ensure that no kinks occur when bending the tubes into
position. If one of the tubes happens to kink and it cannot be fully removed. The tube must be replaced; a kink
in a tube will adversely affect system performance.

When installing the line set, it is imperative that the lines do not come in direct contact with any other surfaces.
Adhering to this practice will further reduce any changes of compressor vibration transmitting into other areas of
the building. When hangers are necessary; use hangers that incorporate isolation sleeves. Depending upon the
length of tubing used, it is possible

Refrigerant Installation Practices – The line sets, recharging, and charge verification must be done by a

professional/licensed refrigeration technician. Industry standard and proper cleaning, nitrogen flow, brazing
techniques, and leak verification must be followed with this installation. Brazed connections points on both the
compressor side and air coil side of the line set is required. It is critical that 2-3 psi of nitrogen be circulated
through the system in order to prevent internal oxidation. Low silver phos-copper braze alloy shall also be used
on all brazed connection points.

Before brazing, wrap the service valves with a heat sink to prevent damage caused by excessive heat. This unit

is shipped with a factory charge, DO NOT open the service valves until the line set has been leak tested,
purged, and evacuated. Depending upon the length of the line set, copper adapters may be needed to

accommodate larger diameter tubing.

Proper evacuation (500 microns) must take place prior to opening the main unit ball valves.

Once the initial charge level has been set, the final charge will then need to be fine tuned based upon the

subcooling and superheat chart.

09/29/2010 19 NI501

A

A

A

Line Set Size Information

Model

10 Feet 20 Feet 30 Feet

Suction Liquid Suction Liquid Suction Liquid

020 ¾” ⅜” ¾” ⅜” ¾” ⅜”
026 ¾” ⅜” ¾” ⅜” ¾” ⅜”
033 ¾” ⅜” ¾” ⅜” ¾” ⅜”
040 ¾” ⅜” ¾” ⅜” ¾” ⅜”
052 ⅞” ⅜” ⅞” ⅜” ⅞” ⅜”
062 ⅞” ⅜” ⅞” ½” ⅞” ½”

See specification chart, page 3, or unit nameplate for factory charge. As stated earlier, this represents the
furnished air coil and 10-foot line set. For additional line set length and charge “tweaking” field add as
required, see pages 18, 21 and 22.

Forced Air Coil – Reference Information

Cased and Uncased Air Coil Dimensions

Uncased

Model Number

RT-SE-020 21.00" 17.00" 12.50" 17.50" 21.50" 15.75" 19.75" 16.25" 20.25" 14.50"
RT-SE-026 21.00" 17.00" 12.50" 17.50" 21.50" 15.75" 19.75" 16.25" 20.25" 14.50"
RT-SE-033 21.00" 21.00" 16.50" 21.25" 21.50" 19.50" 19.75" 20.25" 20.25" 18.50"
RT-SE-040 21.00" 21.00" 16.50" 21.25" 21.50" 19.50" 19.75" 20.25" 20.25" 18.50"
RT-SE-052 21.00" 24.00" 20.50" 25.50" 21.50" 23.75" 19.75" 24.25" 20.25" 21.625"
RT-SE-062 21.00" 24.00" 20.50" 24.50" 21.50" 22.75" 19.75" 23.50" 20.25" 21.625"

Coil

Depth

Uncased

Coil

Width

Uncased

Coil

Height

Cabinet

Width "F"

Cabinet

Width "S"

- Includes TXV

- ¾” MPT primary and secondary drain connections

- Liquid line connect = ⅜”

- Suction line connections: 1.5 to 3.0 ton = ¾”

4.0 to 5.0 ton = ⅞”

09/29/2010 20 NI501

Leaving

ir Width

"L"

Leaving

ir Depth

"P"

Entering

ir Width

"W"

Entering

Air Depth

"D"

Cabinet

Height

"H"

Condensate Drain

Typical condensate drain installation, shown below. The droop in the internal hose should be considered when
planning the drain installation.

If there is no nearby floor drain, a condensate drain pump must be used. See accessory parts list in the back of
this manual.

Leak Testing – The line set must be pressurized and checked for leaks before evacuating and charging the unit.

To pressure the line set, attach refrigerant gauges to the service ports and add nitrogen until the pressure reaches
60-90 psig. Never use oxygen or acetylene to pressure test. Use a halogen leak tester or a good quality bubble
solution to detect leaks on all connections made in the field. Check the service valve ports and stem for leaks. If
a leak is found, repair it and repeat the above steps. For safety reasons do not pressurize system above 150 psig.
The system is now ready for evacuation and charging.

System Evacuation – Ensure that the line set and air coil are evacuated before opening service valves to the

split unit. The line set must be evacuated to at least 500 microns to remove the moisture and air that may still be
in the line set and coil. Evacuate the system through both service ports to prevent false readings on the gauge
because of pressure drop through service ports.

09/29/2010 21 NI501

Charging Procedure

Charging the System – After purging and evacuating the line set, fully open the service valves

counterclockwise. Add the previously calculated R-410A (liquid) into the liquid line service port. Never add
liquid refrigerant into the suction side of a compressor. Start the unit and measure superheat and subcooling.
Keep adding refrigerant until the unit meets the superheat and subcooling values on Unit Operating Conditions
chart.

Superheat and Subcooling

Comments

1. This is a two TXV system – heating, internal to the main cabinet at the water coil refrigerant entrance

and cooling, within the plenum air coil at the air coil liquid entrance.

2. First begin in heating and check superheat associated with the TXV at the water coil (evaporator) as

follows.

3. Depending upon findings and requirement for adjustment, next check subcool and superheat in cooling.

Determining Superheat

1. Measure the temperature of the suction line at the point where the expansion valve bulb is clamped.

2. Determine the suction pressure in the suction line by attaching refrigeration gauges to the schrader

connection on the suction side of the compressor.

3. Convert the pressure obtained in Step 2 to the saturation temperature by using the R-410A

Pressure/Temperature Conversion Chart on page 23.

4. Subtract the temperature obtained in Step 3 from Step 1. The difference is the amount of superheat for

the unit. Refer to Unit Operating Conditions for superheat ranges at specific entering water conditions.

Superheat Adjustment

1. Remove the seal cap from the bottom of the valve.

2. Turn the adjustment screw clockwise to increase superheat and counterclockwise to decrease superheat.

One complete 360° turn changes the superheat approximately 3-4° F. regardless of refrigerant type. You
may need to allow as much as 30 minutes after the adjustment is made for the system to stabilize.

3. Once the proper superheat setting has been achieved, replace and tighten the seal cap. Warning: There

are 8 total (360°) turns on the superheat adjustment stem from wide open to fully closed. When
adjusting the superheat stem clockwise (superheat increase) and the stop is reached, any further
clockwise turning adjustment will damage the valve.

09/29/2010 22 NI501

Determining Subcooling

1. Measure the temperature of the liquid line on the small refrigerant line (liquid line) feeding the air coil

cabinet.

2. Measure the liquid line pressure by attaching refrigerant gauges to the schrader connection on the liquid

line service valve.

3. Convert the pressure obtained in Step 2 to the saturation temperature by using the R-410A

Pressure/Temperature Conversion Chart.

4. Subtract the temperature in Step 1 from the temperature in Step 3. The difference will be the subcooling

value for that unit. Refer to Unit Operating Conditions chart for subcooling ranges at specific enter
water conditions.

Unit Operating Conditions* – First Stage

Entering

Water

Temp °F

50
70
90

Water

Flow

GPM/Ton

Suction

Pressure

psig

Discharge

Pressure

psig

Cooling – No Desuperheater

Suction

Pressure

psig

Discharge

Pressure

psig

Superheat Subcooling

Water
Temp

Rise °F

Air Temp

Drop °F

Entering

Water

Temp °F

50
70
90

Water

Flow

GPM/Ton

Suction

Pressure

psig

Discharge

Pressure

psig

Heating – No Desuperheater

Suction

Pressure

psig

Discharge

Pressure

psig

Superheat Subcooling

Water
Temp

Drop °F

Air Temp

Rise °F

Unit Operating Conditions* – Second Stage

Entering

Water

Temp °F

50
70
90

Water

Flow

GPM/Ton

Suction

Pressure

psig

Discharge

Pressure

psig

Entering

Water

Temp °F

50
70
90

NOTE: Cooling performance based on entering air temperatures of 80° F DB, 67° F WB.

Heating performance based on entering air temperatures of 70° F DB.
* These are nominal expected conditions, will vary from model to model. Refrigeration technician must use his own experience and

judgment to verify proper charge and proper setting of TXV. However, TXV for Geo systems must be set for a balance between heating
and cooling.

Water

Flow

GPM/Ton

Suction

Pressure

psig

Discharge

Pressure

psig

Cooling – No Desuperheater

Suction

Pressure

psig

Heating – No Desuperheater

Suction

Pressure

psig

Discharge

Pressure

psig

Discharge

Pressure

psig

Superheat Subcooling

Superheat Subcooling

Water
Temp

Rise °F

Water
Temp

Drop °F

Air Temp

Drop °F

Air Temp

Rise °F

DB

DB

DB

DB

09/29/2010 23 NI501

PRESSURE

(PSIG)

60
62
64
66
68
70
72
74
76
78
80
82
84
86
88
90
92
94
96

98
100
102
104
106
108
110
112
114
116
118
120
122
124
126
128
130
132
134
136
138
140
142
144
146
148
150
152
154
156
158
160
162
164
166
168
170
172
174
176
178

TEMP

°F

8.5

9.9

11.2

12.5

13.8

15.1

16.3

17.5

18.7

19.8

21.0

22.1

23.2

24.3

25.4

26.5

27.5

28.6

29.6

30.6

31.6

32.6

33.5

34.5

35.4

36.4

37.3

38.2

39.1

40.0

40.9

41.7

42.6

43.4

44.3

45.1

45.9

46.7

47.5

48.3

49.1

49.9

50.7

51.5

52.2

53.0

53.7

54.5

55.2

55.9

56.6

57.4

58.1

58.8

59.5

60.2

60.8

61.5

62.2

62.9

Pressure/Temperature Conversion Chart for R-410A

PRESSURE

(PSIG)

180

182
184
186
188
190
192
194
196
198
200
202
204
206
208
210
212
214
216
218
220
222
224
226
228
230
232
234
236
238
240
242
244
246
248

250

252
254
256
258
260
262
264
266
268
270
272
274
276
278
280
282
284
286
288
290
292
294
296
298

TEMP

°F

63.5

64.2

64.8

65.5

66.1

66.8

67.4

68.0

68.7

69.3

69.9

70.5

71.1

71.7

72.3

72.9

73.5

74.1

74.7

75.3

75.8

76.4

77.0

77.5

78.1

78.7

79.2

79.8

80.3

80.9

81.4

81.9

82.5

83.0

83.5

84.1

84.6

85.1

85.6

86.1

86.6

87.1

87.7

88.2

88.7

89.2

89.6

90.1

90.6

91.1

91.6

92.1

92.6

93.0

93.5

94.0

94.5

94.9

95.4

95.8

PRESSURE

(PSIG)

300

302
304
306
308
310
312
314
316
318
320
322
324
326
328
330
332
334
336
338
340
342
344
346
348
350
352
354
356
358
360
362
364
366
368

370

372
374
376
378
380
382
384
386
388
390
392
394
396
398
400
402
404
406
408
410
412
414
416
418

TEMP

°F

96.3

96.8

97.2

97.7

98.1

98.6

99.0

99.5

99.9

100.4

100.8

101.2

101.7

102.1

102.5

103.0

103.4

103.8

104.2

104.7

105.1

105.5

105.9

106.3

106.7

107.2

107.6

108.0

108.4

108.8

109.2

109.6

110.0

110.4

110.8

111.2

111.6

112.0

112.3

112.7

113.1

113.5

113.9

114.3

114.7

115.0

115.4

115.8

116.2

116.5

116.9

117.3

117.6

118.0

118.4

118.7

119.1

119.5

119.8

120.2

PRESSURE

(PSIG)

420

422
424
426
428
430
432
434
436
438
440
442
444
446
448
450
452
454
456
458
460
462
464
466
468
470
472
474
476
478
480
482
484
486
488

490

492
494
496
498
500
502
504
506
508
510
512
514
516
518
520
522
524
526
528
530
532
534
536
538

TEMP

°F

120.6

120.9

121.3

121.6

122.0

122.3

122.7

123.0

123.4

123.7

124.1

124.4

124.8

125.1

125.4

125.8

126.1

126.5

126.8

127.1

127.5

127.8

128.1

128.5

128.8

129.1

129.4

129.8

130.1

130.4

130.7

131.1

131.4

131.7

132.0

132.3

132.7

133.0

133.3

133.6

133.9

134.2

134.5

134.9

135.2

135.5

135.8

136.1

136.4

136.7

137.0

137.3

137.6

137.9

138.2

138.5

138.8

139.1

139.4

139.7

PRESSURE

(PSIG)

540

542
544
546
548
550
552
554
556
558
560
562
564
566
568
570
572
574
576
578
580
582
584
586
588
590
592
594
596
598
600
602
604
606
608

TEMP

°F

140.0

140.3

140.6

140.9

141.2

141.4

141.7

142.0

142.3

142.6

142.9

143.2

143.5

143.7

144.0

144.3

144.6

144.9

145.1

145.4

145.7

146.0

146.2

146.5

146.8

147.1

147.3

147.6

147.9

148.2

148.4

148.7

149.0

149.2

149.5

09/29/2010 24 NI501

Electrical Hookup

WARNING

DISCONNECT ALL ELECTRICAL POWER BEFORE ELECTRICALLY CONNECTING OR
SERVICING THE UNIT. FAILURE TO DISCONNECT THE ELECTRICAL POWER BEFORE
WORKING ON THIS PRODUCT CAN CREATE A HAZARD LEADING TO PERSONAL INJURY
OR DEATH.

Line Voltage

The nameplate and/or Installation and Operating Manual specification page provides RLA, LRA, and total amps
requirement. Select the proper wire size to comply with your type of wire routing and NEC field wiring
requirements.

 If this unit includes AUX EL module, its own nameplate provides kW and current/voltage requirement.

The field power supply connection is at the compressor contactor, at the end of the line voltage control box.

Disconnect – field provided external safety disconnect is required, see nameplate max amps.
Loop pumps – the loop pump station can be powered at the TB above the contactor. 5-amp fusing is included,

left of terminal block.

Grounding – route and install the proper size ground conductor between the ground lug above the compressor

contactor and the building service entrance panel ground bus. This must be a conductor wire size according to
NEC code for the total amp rating of the installed model. The conduit is not sufficient ground conductor.

WARNING

USE ONLY COPPER WIRE FOR CONNECTION TO THE CIRCUIT BREAKER TERMINALS
AND INSIDE THIS PRODUCT’S CABINET.

WARNING

TO AVOID THE RISK OF ELECTRIC SHOCK OR DEATH, WIRING TO THE UNIT MUST BE
PROPERLY GROUNDED. FAILURE TO PROPERLY GROUND THE UNIT CAN RESULT IN A
HAZARD LEADING TO PERSONAL INJURY OR DEATH.

09/29/2010 25 NI501

EZGEO Controller

EZGEO Features

Review attached HC112 HELPS document which lists the various characteristics and capability of this
controller product.

Application

The EZGEO controller is standard on all Northern Heat Pump models.

Even more specific, this model factory default is mode D and SW OVER = position 1 (-15° OT).

WARNING

IF THERE IS NO AUTOMATIC STANDBY (GAS) OPERATING FROM THE EZGEO FURNACE
TB-W, THE SW OVER DIAL SWITCH MUST BE SET TO Ø POSITION. THIS STATEMENT
RELATES TO MODES B, C, AND D. ONCE THERE IS A LOGIC TRANSFER TO SB, THE
FURNACE MUST FINISH OUT ROOMSTAT-W. THUS THERE IS NO FURNACE OR NO HEAT
THE SYSTEM WILL BASICALLY BE LOCKED UP WAITING FOR HEAT ENERGY TO
SATISFY THE THERMOSTAT.

Room Thermostat

This is general hookup information, before proceeding review previous section – EZGEO Controller – and

determine operating mode for this particular application.

Use conventional (not heat pump with O and compressor Y) heat/cool. This controller is designed to operate

from a basic 1H/1C thermostat. 2H/2C can be used (not recommended), see next section for comments relating
to W2 and Y2 from the roomstat.

It can be mechanical, digital, power robbing, battery operated, setback, etc. If required, set heat anticipator to

0.2. If electronic/digital stat, setup may ask for “cycles per hour”. Since this is a heat pump product, efficiency
relates to long run time, recommend small number (2 cycles per hour).

Note 1: Do not (even with heat pump) use a heat pump thermostat.
Note 2: If programmable roomstat has external sensors, make sure setup is for display monitor only and

any programming for these sensors that has to do with interrupting any output functions, ODT,

auxiliary, setback, etc. are not active or program disabled.

Connect the standard R, W, G, Y stat terminals to the EZGEO board upper left terminal block. If the specific
roomstat requires common or C, this can be picked up from a tab on the board bottom right.

NOTE

The installer must be familiar with the manufacturer’s low voltage wiring terminology, screw
terminal terminology/colors, etc. This manufacturer’s terminology must be related to Northern
Heat Pump’s screw terminal identification within this controller. The intent of this instruction

manual is not to train each installer on the terminology related to the specific product you are

installing.

09/29/2010 26 NI501

Utility Load Control

Bottom 2-screw terminal block marked blue and blu/wht. Remove the jumper and extend the two wires to the
utility furnished control device. For electric energy operation (off-peak) the two blue wires represent contact

closure as shipped. Do not apply external voltage or external power to the blue wires, they are simply

looking for a closed contact during off-peak.

 The maximum “AC noise” on the blue wire is 5 volts, peak to peak. The blue/white TB is actually

common and if grounding is proper as suggested in the next paragraph, this should dampen any effect.
But it is always good practice to run these wires separate from any current carrying line voltage Romex
or other conductors.

 One load control wire pair handles both winter and summer interrupt.
 If load control reverse logic is required, a “closed to interrupt contact” can be connected to SB SW to

COM. Another way to resolve this issue is through the use of an interposing relay. Consult factory if
an interposing relay is required.

 If load management interrupt does not apply, simply leave the blue wires jumpered.

Grounding

Caution – 24 volts common grounding – the installer must determine whether the furnace fan center

COM screw terminal has a good ground bond (not simply furnace skin). If the fan center COM is not
adequately grounded, use a green wire from the EZGEO lower right C tab to a ground bond.

Optional – Alarm Output Annunciator

As shown on hookup drawing NH501, there are provisions for an external buzzer and LED device. When the
Geo HP declares a fault or dead compressor alarm, this device will sound an audible and turn on the LED light.

 The 2-wire hookup can be extended as much as 100 feet (30 meters) using 18 or 20 gauge wire.
 The audible can be turned off with the pushbutton. But if the system is not repaired within 4 hours the

audible will again sound.

 The LED light will continue until the system is repaired and power off reset.
 The system may recover on its own, but the LED will continue indicating there “was” a fault situation.

This LED is only turned off by a power off reset at the disconnect.

 Order R-AL-RS-1

09/29/2010 27 NI501

Visual example only – the exact connections will depend upon operating mode. The ST air supply temperature
probe pictured above is not standard equipment on the split unit.. Review previous section – EZGEO
Controller.

09/29/2010 28 NI501

Temperature Sensors

Outdoor Sensor (OT) – extend sensor to an outdoor location properly

sampling the outdoor temperature. Select a location away from direct
sunlight and where the sensor will not pick up false temperature from the heat
pump outdoor unit, refrigerant line sets, dryer vent, reflection off of steel
siding, etc. Do not install the sensor in any type of enclosure, as this will
falsely trap and pick up radiant sun temperature. Mount the sensor
horizontally on the structure using the screws provided.

Duct Sensor (ST) – install in the warm air plenum at least 12” (31 cm) above heat pump A-coil. Locate to one

side so the air coming through the A-coil passes over the sensor tip. The ST sensor does not have an end cap;
the small black electronic part just within the tube end is the actual sensor. The only purpose of the metal tube
is the protection of the sensor. Best results are obtained by positioning the sensor so the black tip is directly in
the air leaving the A-coil. This air is most often towards the edges of the plenum.

Other Sensor Related Comments

If additional cable length is required, you must use the following rules for extending the cable.

 Use unshielded (low capacitance, preferred twisted) 3 or 4-wire low voltage cable.
 50 feet (15 meters) is maximum (total).
 Do not, under any circumstances, use leftover wires within the normal thermostat cable.
 Route the sensor cable making sure you do not crimp, cut, staple, or damage the cable in any way.
 Keep sensor cables at least 12” (31cm) away from any line voltage wiring, romex, etc.

For easy sensor cable disconnect and reconnect, the WarmFlo board has a plug-in 4-place terminal block.
Before disconnecting, you will notice two red wires are under the red screw and two white wires is under the
COM screw. The black wire represents the data information from each sensor and must be connected to the
appropriate OT or ST screw.

The sensor is polarity specific and is sensitive to incorrect voltage. It must be protected from static voltage, etc.
Do not cross connect or inadvertently short out sensor wires with power on. Permanent destruct damage may
result.

09/29/2010 29 NI501

Gas Furnace Hookup – Mode D

See hookup drawing NH501, the gas furnace wiring is at the EZGEO board bottom left terminal block.

Gas Furnace (or Oil with Fan Center Terminal Wiring Strip)

The control board lower left 6 terminal screw points are used for the furnace interface. However, all 6 are not
necessarily used, based on type of furnace, blower, burner, etc.

24-volt power – for the Split unit (mode D) the power for the EZGEO Controller comes from the gas furnace

transformer.

Basic furnace, PSC blower motor – in addition to R and C above, add W and G.

Variable speed blower, ECM motor, single Y – in addition to the above add Y to Y.

Variable speed blower, ECM motor, available Y1 and Y2 speeds – in addition to the above, the control

board Y goes to furnace Y1 and control board Y2 goes to furnace Y2.

2-stage or variable stage burner – if mode B, C, D and 2-stage furnace burner, program the gas furnace for

high burner internal control (next section also has other options for stat W2).

ECM blower motor speed/setup – the gas furnace blower is setup identical to an air conditioning/gas furnace

arrangement. See model number specification page and determine Y1 and Y2 CFM requirements for this Geo
HP unit. Relate this directly to an air conditioner CFM requirement or CFM per ton. Set the gas furnace bit
switches (or setup technique) for the ECM blower speed/CFM to deliver the proper airflow when the Geo HP
Y1 or Y2 stages are active. These are the direct hardware connections at the furnace terminal block – Y1 and
Y2.

ST Sensor – Installed above A-coil, see page 29.

09/29/2010 30 NI501

Additional Hookup or Special System Equipment Concerns

Additional Room Thermostat Connection Points

On the EZGEO board, upper left, are three optional control tabs – W2, E-GAS, and Y2. These can be used for
troubleshooting or emergency full output energy or with a conventional 2H/2C room thermostat. However,

when considering energy efficiency these points connected to a 2H/2C thermostat is not recommended.

 W2 – mode B, this conditions AUX EL all stages on, with compressor in Y2.
 E-GAS – this conditions the system to standby or transfers the room thermostat W to gas furnace. This

is active for all modes, it should never be used for mode A when there’s no gas furnace connected.

 Y2 – in cooling, this forces compressor to full capacity. It can be an override to the cooling sequence

condition shown in Figures 1, 2, 3, 4.

Special Oil Furnace Comment

This controller is designed to interface directly with a furnace fan center containing 24-volt transformer (40VA

or larger), blower relay, and a “W” function to operate the furnace. If this installation is for an oil furnace with

only oil control “T and T” terminals, a special fan center will need to be added with an isolation relay at the “W”
terminal so only isolated contacts are connected to the oil burner master control “T and T”. Another choice is to
order EE-5053 relay with accompanying HD001 instruction sheet.

Remotely Located Standby Override Switch

On the bottom of the board is an “SB SW” tab. Using an external switch between this “SB SW” tab and a
common tab provides the same function as the two-position system selector switch on the front of your EZGEO
control panel. In this configuration, either of these switches allows the homeowner to manually force the
HVAC system to utilize a fossil fuel system. A closure of the external switch is the equivalent to the system
selector switch being in the “up” or “standby” position.

Important note on cooling mode: To operate in cooling mode, neither of the switches can be in the override

position. Thus, the selector switch on your EZGEO control panel MUST be in the “down” position AND the
external switch must be in “heat pump” or “normal” position in order for the heat pump to operate in cooling
mode. If one or both of these switches are not the proper positions, cooling will not occur.

Load Control, Other Products or Hardware

If there is a need to “pass on” the utility load control receiver function to other heating equipment, radiant floor
boiler, peak interrupter, etc; there is an isolated contact on this control board. Locate tabs COM/EL/SB. In the
electric mode there is an isolated contact between COM and EL. This contact is for low voltage only, 1-amp
maximum.

Note: There may be a 1 or 2 minute delay between this relay contact action and the actual load control

Optional – Alarm Output Annunciator

As shown on hookup drawing NH501, there are provisions for an external buzzer and LED device. When the
Geo HP declares a fault or dead compressor alarm, this device will sound an audible and turn on the LED light.

receiver. This delay coincides with various blower purge functions.

Note: This contact also follows front panel standby switch and all other standby functions such as SOT-

S, etc.

 The 2-wire hookup can be extended as much as 100 feet (30 meters), use 18 or 20 gauge wire.
 The audible can be turned off with the pushbutton. But if the system is not repaired within 4 hours the

audible will again sound.

 The LED light will continue until the system is repaired and power off reset.
 The system may recover on its own, but the LED will continue indicating there “was” a fault situation.

This LED is only turned off by a power off reset at the disconnect.

 Order R-AL-RS-1

09/29/2010 31 NI501

Field Setup or Programming

It is extremely important the installer properly goes through this section and sets up the various switches to
match the installation. Again, refer back to EZGEO Controller section for further details on these setups.

Warning: Power-down reset required whenever changing any of the switch positions on the back side

of the board.

Select Configuration or Hardware MODE – since this manual is dedicated to Split model, must be set on D.

D – Split/Gas

09/29/2010 32 NI501

Switchover Temperature (SW OVER)

This switch is shipped from the factory with a square “GAS” label. This label should be removed ONLY if a
secondary furnace is present and active in the system. The installer should remove the label and adjust this
switch only after reading this manual and understanding the operation of the switch. Select the OT temperature
to interrupt the compressor and transfer to the sequence shown on applicable mode Figures 2, 3, 4. This only
applies when a gas furnace is connected. For all non-SB configurations must be set to 0 position (disable).

0 = Disable 4 = 5° F
1 = -15° F 5 = 10° F
2 = -10° F 6 = 20° F
3 = 0° F 7 = 30° F

Stat Override Timer (SOT)

Again, see the appropriate mode Figures 1, 2, 3, 4 for the sequence action after the SOT timeout (end). The
intent of the SOT is to take care of very unusual heat/cool conditions or building matching situations, the
general sequence relating to OT temperature should take care of proper thermostat cycling without ever reaching
SOT timeout (end). Thus, it is recommended the SOT be a high number.

0 = 30 minutes 2 = 180 minutes
1 = 90 minutes 3 = 270 minutes

Efficiency Setting (Front Panel)

This applies to AUX EL module or supplementary heating only, mode B. With this dial switch the homeowner

can boost the default 110° F (43° C)ST target temp.

Normal = setup value (105° F) (40.5° C)
A = +5° F
B = +10° F

Information

Front panel decal showing efficiency dial and LED’s.

Gas Furnace CFM

See previous page on gas furnace hookup for proper programming of ECM motor for the required CFM output.

Outdoor Temp (OT) Factory Default Settings

Default

ST target temp 96° F (37°C)
Dead compressor ST 85° F (29°C)
OT temp, heating – HI > 20° F (-7°C)
OT temp, heating – LO < 5° F (-15°C)
OT temp, cooling – HI > 80° F (27°C)

09/29/2010 33 NI501

Operation Indicators

Front Panel LED’s

- Hi-limit – when the AUX EL hi-limit probe (automatic reset or manual reset) opens this top red

LED is on. The electric elements will be interrupted via a safety relay circuit whenever this HL
LED is illuminated (mode B only).

- PWR ON – indicates good fuse and 24-volt power source from the furnace terminal block.

- See below for bad sensor indication.

- Status mode – in some ways this can be a utility load control indicator, but there are additional

programmable functions which cause this unit to go to standby (see HC112 EZGEO section and
sequence charts).

- In addition this LED provides monitor for the two alarm conditions.

 Dead compressor – fast pulsing, 1/10 second
 ICM fault – slow pulsing, 1 second

- HP-Y1 – the output “Y” screw terminal is active at 24 volts high. This provides the “Y” input to

the ICM compressor monitor board. Compressor will react as a function of this ICM safety board.

- HP-Y2 – the output “Y2” screw terminal is active at 24 volts high.

- T-stat call – the room thermostat W or Y is active or 24 volts high.

- Gas call – the furnace “W” or terminal block feeding furnace W, 24 volts high.

Override Switch – the front panel slide switch (very similar to standard Electro-Mate DFC) is a direct hardware

disabling of the HP-Y1 and electric elements functions. The room thermostat heat call wire or function is
directly controlling the fossil fuel or gas furnace. This function can also be on a remote switch, see previous
statement for “SBSW” tab.

WARNING

THIS FRONT PANEL MANUAL OVERRIDE SWITCH IS A HARDWARE DIRECT TO GAS
FURNACE FUNCTION. THUS THERE ARE NO BLOWER PURGE CYCLES. IF THE ELECTRIC
ELEMENTS ARE ON AND HOT WHEN SWITCHING TO OVERRIDE AND IMMEDIATELY
ALLOWING THE GAS FURNACE, OVERHEAT ON THE ELECTRIC ELEMENTS AND
POTENTIAL ELECTRO-MATE MANUAL RESET IS POSSIBLE. THIS FRONT PANEL
OVERRIDE SWITCH SHOULD ONLY BE ACTIVATED WHEN THERE IS NOT A ROOMSTAT
HEAT CALL.

Note: This switch must be in the “normal” position during cooling.

ICM board (inside) – fault LED pulses with last open limit condition, see next page.

Sensor Monitor Indicators – in addition to using PC software to readout the temperature sensors, there is a

built-in go/no-go type monitor visible on the green PWR ON second from the top LED.

 If there is detection of miswired or totally inoperative sensor, this LED has a blinking or pulse

mode. By checking the pulsing pattern, the appropriate sensor can be identified.

 OT sensor - 100 ms blink every second
 ST sensor - two, 100 ms blinks every second
 Both bad - ½ second on, ½ second off, alternating.

09/29/2010 34 NI501

Power On, Startup

Before applying power to the heat pump, check the following items:

1. Water supply plumbing to the heat pump is complete and operational.

2. Low voltage wiring of the thermostat and any additional control wiring is complete.

3. Set thermostat to the OFF position.

4. All high voltage wiring is correct including fuses, breakers, and wire sizes.

5. The heat pump is located in a warm area above 50°F [10°C]. Starting the system with low ambient

temperature conditions is more difficult.

6. Manually open water valve on well system to check flow. Never operate the system without adequate

source water ground loop or open loop supply.

7. You may now apply power to the unit. A 1 to 5 minute delay on power up is programmed into the heat

pump before the compressor will operate. This delay prevents short cycling of the unit.

 During this time the blower may be active.
 Verify water flow rate and temperature of the source side flow to be at recommended levels.

8. The source side water flow rate is at the required level, see specification page. Low water temperature

starting may require flow reduction until the system is up to operating temperature.

The following steps will assure that your system is heating and cooling properly. After the initial time-out
period is completed the heat pump is now ready for operation. Note: EZGEO, HC112, sequence charts (mode
A, B, C, D) determine compressor staging.

1. Place the thermostat to the “HEAT” position. Turn the thermostat up to activate a call for heat. The

compressor should start.

2. After the unit has run for about 3 minutes, check the source side supply and return water temperature. A

water temperature decrease is normal in the heating mode, but the specific operating water temperature

can effect the water flow rate (GPM) stated in the specification table.

3. Verify warm air temperature rise and loop source water decrease are approximately as stated in the

specification table, page 3.

4. Turn the thermostat to the off position. The compressor will shut down in a few seconds.

5. Place the thermostat in the “COOL” position. Next turn thermostat down to active a call for cooling.

The compressor will start after a 5 minute anti-short cycle period from its last shutdown.

6. After the unit has run about 3 minutes, check the source side supply and return water temperatures. A

water temperature rise is normal in the cooling mode.

7. Verify cool air temperature drop and loop source water increase are approximately as stated in the

specification table, page 3.

8. Instruct the owner on correct operation of the thermostat and heat pump system.

09/29/2010 35 NI501

Operational Tips

ICM Board – The ICM board performs the functions controlling the compressor operation: system lockout,

compressor anti-short cycle, and a five minute delay after power is applied.

The control will begin the 5-minute time delay upon a Y call from the thermostat. After the time delay expires,
the compressor contactor will be energized as long as the high and low pressure switches are closed. If either
switch is open after the delay expires, the compressor will not energize. If either switch opens while the
compressor is energized, it will de-energize immediately and begin the anti-short cycle delay. The compressor
will not be allowed to turn on again until the anti-short cycle delay expires and both pressure switches are
closed. The flow switch will have a 30-second bypass timer in which the control will ignore an open flow
switch for the first 30 seconds. If the flow switch remains open after the 30-second bypass timer expires, the
unit will de-energize the compressor and begin the anti-short cycle delay. If the control experiences three high
pressure, low pressure, or flow switch faults in a 60-minute period, it will lock out the compressor and energize
the fault output. A manual reset of power will be required to reset the lockout condition.

Problems that could cause a lockout situation include:

1. Water flow problems

2. Air flow problems

3. Internal heat pump operation problems

The control has a status LED to indicate which type of fault or lockout has occurred. If a high pressure fault or
lockout occurs, the status LED will blink once. If a low pressure fault or lockout occurs, the status LED will
blink twice. If a flow switch fault occurs, the status LED will blink three times.

The anti-short cycle function puts a time-out period of 5 fixed ±20% minutes on the compressor before re-

starting. This function protects the compressor from repeated on/off operation in the event of a loose wire or
faulty controller.

4. Cold ambient air temperature conditions

ICM Fault Code LED

1 blink = high pressure cutout (550 PSI)
2 blink = low pressure cutout (40 PSI)
3 blink = Flow switch open

CAUTION

The front panel override switch should not be changed during a heat call. There are no purge

cycles when manually changing the override switch with an active heat call and could cause an
undesired overheat situation

High and Low Pressure Switches – The heat pump is equipped with both high and low pressure switches that

shut the unit off if the refrigerant pressure exceeds 550 PSI or goes below 40 PSI. The freeze protection switch
(on open loop systems) will also activate the lockout at 40 PSI in the heating mode to protect the water coil
against freeze rupture. Do not reset a well water system in the heating mode without first verifying water flow.

DO NOT reset the system more than once.
Repeated resetting of the lockout can cause serious damage. If same lockout occurs contact your service
dealer immediately.

Low Pressure

Cut-out pressure 40 PSI 550 PSI 1 blink = high pressure cutout

Cut-in pressure 65 PSI 420 PSI 2 blink = low pressure cutout

09/29/2010 36 NI501

Pressure Switch Settings

High Pressure

Switch

Switch

Fault Code LED

Troubleshooting – EZGEO Control

Comment – Split, mode D, does not required ST sensor. Certain items below only relate to modes B and C.
Sensor Temperature Calibration – both remote sensors are digital electronic and factory calibrated. Normally

these do not require field calibration or verification. However, if sensor temperature error is determined, use
special PC software disc and PC serial port cable. The PC screen has direct readout of both temperatures, allows
a visual determination of WarmFlo internal temperature settings, and can be used to offset either temperature
sensor for troubleshooting and demonstration purposes. This is especially valuable during summer installation.

Override, “E” Tab Input – during a normal roomstat heat call and W2 is jumpered to W, it brings on all four

stages and essentially bypasses any temperature sensing or stage modulation functions. In other words, with an
W2 input (still need the normal W stat input) this is simply a turn-on/turn-off device.

During a normal roomstat heat call and E-GAS is jumpered to W, it forces a standby (SB) action.

During a normal roomstat cool call and Y2 is jumpered to Y, it forces a compressor to full capacity.

SOT bypass – factory checkout procedure can jumper out (shorten time) this timer.
Bad sensor, safety – if the internal logic detects open sensor wire, incorrectly wired sensor, or some bad sensor

transmitted value conditions; the green LED reverts to a pulsing mode. Basically the appropriate sensor is set
internally to a 0° value and the WarmFlo main board only allows stage 1 and stage 2 on.

- OT sensor – approximately 1/10 second blip every ½ second

- ST sensor – two, 1/10 second blips every ½ second

Bad sensor, operating default condition – the detection of bad sensor forces the controller to a fixed stage

operation.

Internal fuses – the internal desuperheater pump and the source loop pump station terminal block have internal

fuses. These are located above the compressor contactor.

Troubleshooting/Repair Helps

1. This EZGEO controller contains several interference suppression components, but as an electronic logic

2. The terminal blocks for control wire hook-up are designed for a wire insertion and screw clamp down.

3. Use general heating system logic information and basic understanding of the terminal block wiring

4. The outdoor sensor must be located outdoors for this controller to correctly operate. Do not leave the

- Both bad – ½ second on and ½ second off, alternating

- ST sensor

 Stages 1 and 2 on, stages 3 and 4 off (5 kW maximum)
 The PC screen reads “254” or “BAD”

- OT sensor

 Set to a default of 2° F (-17° C), see Figures 1, 2, 3, 4
 The PC screen reads “254” or “BAD”

- The external decal provides the fuse size and details.

product, unpredictable and unusual transients or interferences may sometimes cause strange results. If
the EZGEO controller is “acting strange”, one immediate step would be power down reset. Simply turn
off the 24-volt source power (probably furnace or air handler circuit breaker), when the green LED goes
out, count to 10, and re-energize power supply.

If there is no wire connected and the screw is loose, the screw may not necessarily make a good
electrical contact to the inside components. Example – if you are jumpering the thermostat terminals
without thermostat wire connection or if you are attempting to measure voltage on the screw head, you
may get erroneous or unpredictable results if the screw is not tightened down.

functions when measuring voltage to determine proper operation of this module.

outdoor sensor “hanging in conditioned space” and attempt to run this system. Note: OT sensor tip must
be up.

09/29/2010 37 NI501

Alarm/Fault Active

The status LED and alarm output continue until power-off reset. The EZGEO system will attempt to maintain
room temperature or prevent freeze-up.

- Mode A – by definition, no backup, at each roomstat W cycle, compressor will retry.

- Modes B, C, D – with gas furnace standby roomstat W is transferred to gas furnace operation.

- Mode B, SW OVER = 0 – AUX EL will be active and do the heating.

- Cooling – same as mode A, each thermostat cycle will attempt a compressor.

Note: Do not repeatedly cycle the compressor and cause consecutive faults. This will result in permanent

compressor damage and perhaps void warranty. If the Geo system goes into a fault mode, it has already made
three attempts to clear the limit condition, repeated cycling of the roomstat will not do any good, it will simply
cause damage. Call for service.

Backup/freeze-up – the intent of modes B, C, D with either AUX EL or gas furnace is to prevent freeze-up. If

this Geo system is installed without backup (mode A) there is no secondary means of creating heat.

Correct use of mode selection – by definition modes B, C, D installation include gas furnace and/or AUX EL

module. If the system is setup in either B, C, D and there is no gas furnace and/or AUX EL freeze-up may still
occur because the roomstat is assuming a heat source which will bring up the temperature to satisfy the
roomstat.

WARNING

WHEN CONFIGURED WITH A GAS FURNACE AND/OR AUX EL (MODES B, C, D) IT IS THE
USER’S RESPONSIBILITY TO HAVE CIRCUIT BREAKERS TURNED ON, GAS IN THE TANK,
GAS VALVES OPEN, AN OPERATIONAL GAS FURNACE, ETC. THE EZGEO CONTROLLER
CANNOT DETECT “NO GAS IN THE TANK”.

Overheat Plenum, Control Override

When AUX EL stages are not active, the ST sensor also control compressor functions. This also prevents
compressor and gas furnace on at the same time (mode D/refrigerant coil in plenum).

- ST > 105° F – compressor Y2 turned off

- ST > 110° F – compressor off

Operation continues to the end of heat call cycle or if ST < 100° F (38° C) compressor Y2 will re-energize.

EZGEO Bypass

Behind the front panel hinged door the various wires from the EZGEO board terminate on a Geo standard
terminology terminal block. If necessary to prevent building freeze-up, etc. the wires from the EZGEO board
can be disconnected from this terminal block and the room thermostat (or another heat pump type roomstat) can
be transferred to this terminal block to run the compressor/heat pump in an emergency mode.

- R to Y1 and Y2 – compressor high capacity and blower at full airflow.

- RV – can be left unterminated for heating (NHP concept design is reversing valve high during cooling)

- G – not needed.

- Fault – monitored output only, not needed.

Gas furnace only option, operating mode B, C, D – with EZGEO board disconnected, roomstat can go

directly to gas furnace W and appropriate blower terminals. This is assuming gas furnace has its own blower.

Front panel override switch – if mode is B, C, or D and gas furnace is active via EZGEO board with a

potential compressor problem (probably fault LED on) the front panel switch in the up position will transfer the
roomstat to the gas furnace. Depending upon the blower configuration, it should follow with the functioning
gas furnace, but local HVAC contractor needs to verify.

09/29/2010 38 NI501

Troubleshooting – General

Problem Possible Cause Possible Solution

Unit does not run

Tripped breaker/blown
fuse

Blown controller fuse Replace controller fuse. Replace with correct fuse.

Low voltage supply

Low voltage in circuit

Thermostat

Interruptible power Check incoming supply voltage

Thermostat

Reset circuit or replace fuse. Always check and use correct size

Contact local power company if voltage is below that specified for
your unit

Check the 24 volt transformer for voltage less than 18 volts or
possible burnout.

Set thermostat on "Cool" and lowest temperature setting and unit
should run. Set thermostat on "Heat" and highest setting and unit
should run. If in both cases the unit fails to run, thermostat could be
wired incorrect or thermostat is faulty. To prove, disconnect
thermostat wires on the unit and jumper between "Red", "Yellow"
and "Green" terminals and unit should run.

Check settings, calibration and wiring and if thermostat has an
anticipator set at 0.2

Hydronic pump runs
but compressor does
not or compressor
short cycles

Wiring Check for loose or broken wires at compressor, capacitor or contactor

Blow fuse Replace controller fuse. Replace with correct fuse.

High or low pressure
controls

Defective capacitor Check, if defective, remove and replace. Wire correctly.

Voltage supply low

Low voltage circuit Check 24 volt transformer for voltage under 18 volts or burnout.

Compressor overload open

Compressor motor
grounded

Compressor windings open

Unit could be off on the high or low pressure cutout control. Check
water GPM, ambient temperature and loss of refrigerant. If still
failing to run, check for faulty pressure controls. Replace if needed.

If voltage is below minimum required, call local power company.
Check compressor voltage for possible open terminal.

An internal compressor overload is used in all cases. If compressor
is too hot, the compressor will not reset until cooled off. It may be
defective or an open overload. Replace compressor.

Internal winding grounded to case. Replace the compressor. If burnt
out, replace the liquid line filter drier also.

Check continuity of the windings with an ohm-meter. If windings
are open, replace compressor and liquid line drier.

09/29/2010 39 NI501

Unit Short Cycles

Thermostat

Improper thermostat location (e.g. near kitchen). Anticipator should
be 1.0 or 1.2

Defective compressor overload, check and replace if necessary. If

Compressor overload

the compressor is running hot, it may be due to insufficient
refrigerant charge.

Blow fuse Replace controller fuse. Replace with correct fuse.

Aqua stat The differential is set too close. Increase differential setting.

Wiring and controls Loose connection or control contactor defective.

Loop fluid Lack of pressure, temperature and/or quantity of water.

Insufficient cooling or
heating

Loss of conditioned air

Thermostat

Airflow across fan coil

Refrigerant charge

Compressor

Reversing valve

Desuperheater

Check ductwork design or introduction of ambient air through
windows and doors.

Improper thermostat location (e.g. near kitchen). Anticipator should
be 0.2

Lack of airflow or improper distribution of air. Check motor speed
and duct size. Also check filter for reduced air flow.

Low refrigerant charge causes inefficient operation. Adjust only after
checking CFM and GPM

If discharge pressure is low and suction pressure too high,
compressor is not pumping properly. Compressor needs to be
replaced.

Defective valve creating bypass of refrigerant from discharge to
suction side of compressor. When replacing reversing valve, direct
heat away from valve and protect by wrapping in wet cloth.

Circuit (in-line fuse) should be disconnected in winter to allow full
heat load to house.

Thermostat setting Check setting. Is it below room temperature?

Defective thermostat Check operations of thermostat. Replace if defective.
No Response in
Heating Mode

Wired incorrectly Check for loose, broken or incorrect wiring.

High aqua stat setting

09/29/2010 40 NI501

Heat pump is trying to heat water that is too hot. Reduce the setting
on the aqua stat.

Reversing valve does not

shift

Defective solenoid valve not energizing. Replace coil on valve.

Does Not Cool

(only heats)

Noisy Operation

Reversing valve does not

shift, valve is stuck

Aqua stat is set too low

Insufficient antifreeze

Compressor

Contactor

Rattles and vibrations

The solenoid valve is de-energized due to incorrect wiring at the unit
or thermostat. Replace if valve is tight or frozen and will not move.
Switch to cooling from heating a few times to help loosen valve.

Heat pump is trying to cool water too low. Increase setting on aqua
stat.

Water is freezing in hydronic coil. Check antifreeze level and add if
necessary to maintain proper freeze protection.

Make sure compressor is not in direct contact with cabinet. Cold
surroundings can cause liquid slugging. Increase ambient
temperature.

The "clattering" and "humming" noise in the contactor could be due
to control voltage less than 18 volts. Check for low supply voltage,
low transformer output or extra long runs of thermostat wires. If the
contactor contacts are pitted, or corroded, or coil is defective, repair
or replace.

Check for loose screws, panels or internal components. Tighten and
secure. Copper piping could be hitting the metal surfaces, isolate if
necessary.

Undersized ductwork will cause high airflow velocities and noisy

Water and airborne noises

operation. Excessive water through the water cooled heat exchanger
will cause a squealing sound. Check for correct water flow for good
operation and to eliminate noise.

Pump cavitation Purge air from closed loop system.

09/29/2010 41 NI501

Accessories/Options

Fault/alarm external annunciator R-AL-RS-1
Fuse – source loop pump, 10A UFUSE1799
Fuse – desuperheater pump, 3A UFUSE1796
Open loop, freeze limit, 39° F (4° C), pipe mounted 6047
Sound vibration pad R-PAD-2735-1

Part Number

09/29/2010 42 NI501

Electro-HELPS XIII

HELPS – EZGEO Controller

All functions and definitions will apply to all NHP models, see appropriate model or type. Use Installation
Manual to determine which part of this Helps document applies.

This Electro Industries’ exclusive controller provides several installer and user-friendly functions for Geo heat
pump applications. It will be helpful to grasp the EZGEO concept prior to studying the mode configuration
charts and sequence of events.

First, this is a list of features/functions which are an integral part of this EZGEO system.

 Geo source, forced air – EZGEO is standard on all Electro Industries’ models.
 Geo source, split – EZGEO is standard on all Electro Industries’ models.
 Room thermostat – conventional or commonly called 4-wire stat required.
 Application mode selection – 4-position dial switch allows installer to select the mode that fits the

hardware/usage configuration.

 Outdoor temperature sensing (OT) – determines compressor staging, auxiliary electric (when

applicable) and/or switchover to gas.

 Two-stage compressor (Copeland) – sequenced by outdoor temperature (OT) and SOT timeout, see

function charts – Figures 1, 2, 3, 4.

 Forced air supply temperature sensing (ST) – used for the “dead compressor” alarm and controls

compressors if ST is too high – zone dampers, accidental gas furnace, full load to high, etc. – where
AUX electric is installed (mode B only) this regulates AUX EL module based upon heating needs and
comfort.

 Alarms or fault notification – front panel yellow EL LED pulses at two different rates.

o After compressor control board (ICM) has sequenced through three retries.
o Dead compressor, plenum temperature is less than set point (factory default 85° F).

 Interface and control associated with utility control receivers (LMC or blues).
 Standby (SB) – forced function by LMC, front panel switch, optional remote switch, E-GAS, alarm, or

stat override timer (SOT). Also, for modes B, C, D when OT is below SW OVER set point.

 Dual fuel – gas furnace with split models (RT-SE Series), mode D.

o This is also possible with other Geo units (two blower) but special consideration needs to be

Mode dial switch – installer must determine application/configuration and set up as required.

Mode

Switch

A Geo only N/A

B

C Geo/gas Value No AUX EL, gas furnace, auto SB, utility load control
D Split/gas Value No AUX EL, gas furnace, auto SB, utility load control

SW OVER dial switch – if the OT sensor temperature is below this set point (at R to W start) the action shown
on the appropriate Figures 2, 3, 4 mode sequence chart takes place. Remains to end of stat cycle. Notice –
mode B has two conditions, correct position of SW OVER is very important.

 If configured with AUX EL only (no gas), must set to 0 position.
 If no gas is connected or operational and SW OVER is set in a non-0 position, cold air only could result

because the stat W cannot be satisfied without a heating source.

addressed for ducting, airflow arrangements, both blowers, etc. (modes B and C).

Mode SW OVER Configuration

No AUX EL, no gas, no auto SB, but load control can interrupt
compressor for cooling (not heating)

Geo/AUX EL 0

AUX EL (with compressor supplement or emergency), utility
load control, etc.
AUX EL, gas, auto SB, utility load control, etc. AUX EL is

Geo/AUX EL/gas Value

compressor supplement above SW OVER value, below SW
OVER point gas has priority.

09/17/2010 1 HC112

Heat/cool sequence – reference the Figures 1, 2, 3, 4 function sequence charts. These are selected or used
based upon the application or setup mode (mode dial switch, back of EZGEO board, see above). Added
information for the column headings:

 Stats – represents the 4-wire stat W (heat) or Y (cool) call.
 OT – the range or outside temperature window for the various staging functions. This is checked at W

heat call and a second time at 10 minutes.

 SOT – the stat override timer, represents the run time following the stat call. Timing begins at W or Y

high and at the timing end a specific action results.

 SB – standby, interrupts all electric source or energy heating (compressor and AUX EL), converts or

transfers the stat W function to gas/oil as shown on the sequence charts. The return action from the
listed initiating standby functions is different.

- SOT, SW OVER, OT chart line – continue to the end of stat W heat call

- Alarm – continues until power off reset

- LMC, SW OVER, E-gas (heating) – when function ends, clears SB, back to appropriate

sequence chart line (as if there is a new W call), SOT is reset

- LMC, override switch (cooling) – clears with end of function, SOT is not reset, blower = G

 Heat pump three staging functions:

- Off – compressor not running

- Y1 – compressor contactor for run and low capacity

- Y2 – compressor solenoid for high capacity

 Blower, ECM type – the nominal speed or CFM related to each specific model/size is programmed into

the ECM motor. These nominal CFM’s are triggered or controlled by three functions.

- G – continuous air

- Y1 – relates to compressor part capacity

- Y2 – relates to compressor full capacity

 AUX EL – when auxiliary is installed (ordered separate) and the provided cable (standard WF

control/interface) is plugged into EZGEO board J1 (with a mode B only) these stages become active.
The ST temperature relating to the ST-target factory default plus the front panel efficiency dial is the
final determination on which stages are actually heating.

- STG 1 – first 5 kW

- STG 2-4 – the remaining connected or installed stages

 Gas W – the mode B, C, or D functions when the gas furnace should be running. There also is an

attempted safety ST < 100° F sensing point and logic which does an EZGEO reset after 30-minute gas W.

 SW OVER – the OT sensor is reporting a temperature value less than the SW OVER dial switch

setting, switch to standby (SB) or gas.

 Alarm

– shows the two alarm conditions and the action based upon the appropriate mode settings.

 Status front panel yellow EL LED – The alarm condition can be reset or cleared but the LED

continues to pulse until there’s actual power off and power cycled back on.

 LMC – load management control or utility load control function, blue wires.

Variables/factory defaults – can be changed with PC software, listed are the factory default values.

Default

ST-target temp 96°
Dead compressor ST 85°
OT temp, heating – OT > 20°
OT temp, heating – OT < 5°
OT temp, cooling – OT > 80°

Efficiency dial, front panel – this is a “boost” temperature function to the setup ST-target temp.

 0 = normal = download value
 1 = A = download value + 5
 2 = B = download value + 10
 3 through 7 are programmed the same as normal

Front panel LED – see installation manual Observation Indicators section for detail.

09/17/2010 2 HC112

SOT time dial switch – this is a 4-position rotary switch which begins counting time with each stat W (heat) or
each stat Y (cool) input. Depending upon the dial switch setting (chart in installation manual, Field Setup
section) action results after the selected minutes have elapsed. Figures 1, 2, 3, 4 charts provide this sequencing
information.

 Heating – at the end of LMC or SB, the SOT start time is reset to 0.
 Cooling – at the end of LMC, the SOT start time is not reset, as the SOT times out the system will go to

compressor full capacity.

ECM blower motor – this controller provides three outputs which coincide with G and heat pump stage Y1 and
Y2. Whenever the AUX EL (mode B) is activated the blower is Y2 speed. However, the furnace TB outputs
only apply to mode D (split) because the blower is external. For the configurations where the blower is within
the Geo cabinet, the blower speeds are directly tied (hardware) to compressor Y1 and Y2.

 The actual blower size, programming, and CFM output relate to the specific Geo HP model.

AUX EL (KN-**) electric heat module – can only apply to mode B (concerning mode D, there is

consideration for electric furnace, Electro-Mate with gas furnace, etc. but this is not documented). Also must be
strip heat module or WarmFlo compatible with this EZGEO J1 cable.

1. Applies to mode B only.

2. Setup determines an “ST-target temp” which is similar to DT related with EZ-Mate or EB-A type

temperature set point. The operating set point is ST-target plus front dial boost selection.

3. This ST-target temp can be increased with the front dial boost setting, see page 1.

4. When the attached mode B sequence chart has checkmarks in STG1, stage 1 only is active and operates

at ST-target temp and boost.

5. When the mode B sequence chart has checkmarks in STG2-4, all stages operate at ST-target temp and

boost.

Note: This supplement electric module can only operate with the heat pump/compressor Y1 or Y2 functions.
Because the blower is hardware connected to the HP-Y1 and HP-Y2 terminal block, the compressor must be
active. If there is a hardware configuration arrangement where heating is needed below compressor plus AUX
EL, that configuration must include a gas (or fossil fuel) furnace which is activated by SW OVER. However,
under special short term installation conditions, if there is a desire to run AUX only (without compressor) the
yellow wire at the ICM board Y tab can be disconnected.

Special LMC comment – with mode B and hardware configuration of all three heat sources, LMC causes auto
SB/gas and gas continues to the end of SB. SB can happen in addition to LMC (see page 1 center). However,
SB to gas has priority over Geo/AUX EL. W2 activates full AUX EL.

Alarms – EZGEO board has two functions, the Figures 1, 2, 3, 4 sequence charts provide the action when either
of these alarms are active.

 Fault is the output of the Geo unit internal ICM board indicating there has been three consecutive limit

or flow switch failures. The ICM board holds off the compressor until there is a power off reset. Where
standby gas or AUX EL exist (B, C, D) heating will continue with the roomstat W.

 ST < 85° F is a setup value referred to as dead compressor ST. 10 minutes after each new roomstat W

ST is monitored. If ST ever falls below the setup value a 30-minute timer is started (because there may
also be an ICM board fault coincident with this). At the end of the 30 minutes if ST is still less than the
setup value the unit switches to standby. The system remains in standby to the completion of stat W.
Note: This only applies when there is no AUX EL active.

09/17/2010 3 HC112

09/17/2010 4 HC112

Mode A – NHP Geo, Function Sequence, Figure 1

SOT Heat Pump Blower AUX EL

STAT OT

Start End

SB

Off Y1 Y2 G Y1 Y2 STG 1 STG 2-4

Gas W SW

OVER

Alarm

EL

LED

1 W > 20







+ N/A



2 W



  

+ +



3 W 5-20



  

+ +



4 W



  

+ +



5 W < 5



  

+ +



6 W



  

+ +


7
8 W Fault



T + Fault P

9 W



T ST < P
10
11
12
13
14
15 Y < 80







+



16 Y



  

+ +



17 Y > 80



  

+ +



18 Y



  

+ +



19 Y LMC



T Off
20 Y Fault

  

+ + Fault P

21 Y2

  

+ +



 = EZGEO internal action or on

+ = Hardware within Geo unit (BL Y1 and Y2, not G)
T = T-stat can do “FAN ON” G
LMC = Utility receiver, on-peak

09/17/2010 5 HC112

Mode B – NHP Geo, Function Sequence, Figure 2

SOT Heat Pump Blower AUX EL

STAT OT

Start End

SB

Off Y1 Y2 G Y1 Y2 STG 1 STG 2-4

Gas W SW

OVER

Alarm

EL

LED

1 W > 20







+



2 W



  

+ +



3 W 5-20



  

+ +



4 W



  

+ +





5 W < 5



  

+ +

 

Ø



6 W



  

+ +

 

Ø



7 W

  

T

 

Off
8
9 W LMC



T



Off

10 W Fault

  

+ +

 

Ø Fault P

11



Fault





+

 

Fault P

12 W X X X



X X X X < 85 P

13 W2

  

+ +

 



14
15 Y < 80







+



16 Y



  

+ +



17 Y > 80



  

+ +



18 Y



  

+ +



19 Y LMC



T Off

20 Y

  

+ + Fault P

21 Y2

  

+ +



 = EZGEO internal action or on

+ = Hardware within Geo unit (BL Y1 and Y2, not G)
T = T-stat can do “FAN ON” G
X = Not used, ST has AUX EL temp.
LMC = Utility receiver, on-peak
Line 6/7 and 10/11 are OR, depending upon SW OVER setting
SW OVER  means non-Ø setting, OT > setting no action, OT < setting the action shown in the appropriate line

09/17/2010 6 HC112

Mode C – NHP Geo, Function Sequence, Figure 3

SOT Heat Pump Blower AUX EL

STAT OT

Start End

SB

Off Y1 Y2 G Y1 Y2 STG 1 STG 2-4

Gas W SW

OVER

Alarm

EL

LED

1 W > 20







+



2 W



  

+ +



3 W 5-20



  

+ +



4 W



  

+ +



5 W < 5



  

+ +



6 W

  

T



Off
7
8 W

 

T

 

Off

9 W LMC



T



Off

10 W



Fault





+



Fault P

11 W

 



< 85 P

12
13
14
15 Y < 80







+



16 Y



  

+ +



17 Y > 80



  

+ +



18 Y



  

+ +



19 Y LMC



T Off

20 Y Fault

  

+ + Fault P

21 Y2

  

+ +



 = EZGEO internal action or on

+ = Hardware within Geo unit (BL Y1 and Y2, not G)
T = T-stat can do “FAN ON” G
LMC = Utility receiver, on-peak

09/17/2010 7 HC112

Mode D – NHP Geo, Function Sequence, Figure 4

SOT Heat Pump Blower AUX EL

STAT OT

Start End

SB

Off Y1 Y2 G Y1 Y2 STG 1 STG 2-4

Gas W SW

OVER

Alarm

EL

LED

1 W > 20





 



2 W



    



3 W 5-20



    



4 W



    



5 W < 5



    



6 W

  

T



Off
7
8 W

 

T

 

Off

9 W LMC



T



Off

10 W



Fault



T +



Fault P

11
12
13
14
15 Y < 80





 



16 Y



    



17 Y > 80



    



18 Y



    



19 Y LMC



 

Off

20 Y Fault

    

Fault P

21 Y2

    



 = EZGEO internal action or on

+ = Hardware within Geo unit (BL Y1 and Y2, not G)
T = T-stat can do “FAN ON”
LMC = Utility receiver, on-peak

TXV-C

PP

PP

GEO

LOOP FIELD

7/8

1/2

7/8

1/2

TXV-H

1/2

LWT

EWT

AIR COIL

COMP

F/D

PT-1 LL

PT-2

HL

LOOP­COIL

SDW­COIL

DW-RT

DW-ST

RV

- - - - - - - - - - - LINE SET - - - - - - - - - -

- - - LINE SET - - -

BV

BV

FL

BL

PT-1A

REC

T-3

Name

COMP Compressor

HL

Pressure high limit

LL

Pressure low limit

PT

Pressure test port

SDW-COIL Supplementary heat exchanger

DW-ST Ref : DW supply

DW-RT Ref: DW return

RV Reversing valve

BV Ball valve

AIR

COIL Air heat exchanger

BL

Ref: Blower

TXV-C

Expansion

valve - cool

TXV-H

Expansion

valve - heat

F/D

Filter/dryer

LOOP COIL

Source heat exchanger

P

Ref: Loop pump

FL

Flow switch

EWT

Ref: Loop entering

LWT

Ref: Loop leaving

T

Temperature test point

REC

Receiver

NR501 P1

Rev. B 09-17-2010

NORTHERN HEAT PUMP

SPLIT SYSTEM

- HEAT MODE

1

4.0 TON TO 5.0 TON UNITS USE 7/8” PIPE, 1.5 TON TO 3.0 TON USE 3/4” PIPE.

NOTES:

2

4.0 TON TO 5.0 TON UNITS USE BALL VALVES SIZED FOR 7/8” PIPE, 1.5 TON TO

3.0 TON ARE SIZED TO USE 3/4” PIPE.

1

1

2

T-3

T-3A

PT-3

T-2A

TXV-C

PP

PP

GEO

LOOP FIELD

7/8

1/2

7/8

1/2

TXV-H

1/2

LWT

EWT

AIR COIL

COMP

F/D

PT-1 LL

PT-2

HL

LOOP­COIL

SDW­COIL

DW-RT

DW-ST

RV

- - - - - - - - - - - LINE SET - - - - - - - - - -

- - - LINE SET - - -

BV

BV

FL

BL

PT-1A

REC

T-3

Name

COMP Compressor

HL

Pressure high limit

LL

Pressure low limit

PT

Pressure test port

SDW-COIL Supplementary heat exchanger

DW-ST Ref : DW supply

DW-RT Ref: DW return

RV Reversing valve

BV Ball valve

AIR

COIL Air heat exchanger

BL

Ref: Blower

TXV-C

Expansion

valve - cool

TXV-H

Expansion

valve - heat

F/D

Filter/dryer

LOOP COIL

Source heat exchanger

P

Ref: Loop pump

FL

Flow switch

EWT

Ref: Loop entering

LWT

Ref: Loop leaving

T

Temperature test point

REC

Receiver

NR501 P2

Rev. B 09-17-2010

NORTHERN HEAT PUMP

SPLIT SYSTEM

- COOLING MODE

1

4.0 TON TO 5.0 TON UNITS USE 7/8” PIPE, 1.5 TON TO 3.0 TON USE 3/4” PIPE.

NOTES:

2

4.0 TON TO 5.0 TON UNITS USE BALL VALVES SIZED FOR 7/8” PIPE, 1.5 TON TO

3.0 TON ARE SIZED TO USE 3/4” PIPE.

1

1

2

T-3

T-3A

PT-3

T-2A

Northern Heat Pump Residential

Limited Product Warranty

Effective November 1, 2009

Northern Heat Pump, LTD. warrants to the original owner, at the original installation site, for a period of
three (3) years from date of original purchase, that the product and product parts manufactured by
Northern Heat Pump, LTD. are free from manufacturing defects in materials and workmanship, when
used under normal conditions and when such product has not been modified or cha nged in any manner
after leaving the plant of Northern Heat Pump, LTD. If any product or product parts manufactured by
Northern Heat Pump, LTD. are found to have manufacturing defects in materials or workmanship, such
will be repaired or replaced by Northern Heat Pump, LTD. Northern Heat Pump, LTD., shall have the
opportunity to directly, or through its authorized representative, examine and inspect the alleged defective
product or product parts. Northern Heat Pump, LTD. may request that the materials be returned to
Northern Heat Pump, LTD. at owner’s expense for factory inspection. The determination as to whether
product or product parts shall be repaired, or in the alternative, replaced, shall be made by Northern Heat
Pump, LTD. or its authorized representative.

TEN YEAR (10) LIMITED WARRANTY ON REFRIGERATION COMPONENTS

Northern Heat Pump, LTD. warrants that the compressor, reversing valve, expansion valve and heat
exchanger(s) of its products are free from defects in materials and workmanship through the tenth year
following date of original purchase. If any compressor, reversing valve, expansion valve or heat
exchanger(s) are found to have a manufacturing defect in materials or workmanship, Northern Heat
Pump, LTD. will repair or replace them at their discretion.

FIVE YEAR (5) LIMITED WARRANTY ON OPEN WIRE ELEMENTS

Northern Heat Pump, LTD. warrants that the open wire elements of its products are free from defect s in
materials and workmanship through the fifth year following date of original purchase. If any open wire
elements are found to have a manufacturing defect in materials or workmanship, Northern Heat Pump,
LTD. will replace them.

Northern Heat Pump, LTD. shall cover labor costs according to the Repair / Replacement Labor
Allowance Schedule for a period of three (3) years from the date of original purchase, to the original
owner, at the original installation site on all parts excluding the compressor, reversing valve, expansion
valve, and heat exchanger(s). Northern Heat Pump, LTD shall cover labor costs according to the Repair /
Replacement Labor Allowance Schedule for a period of five (5) years from the date of original purchase,
to the original owner, at the original installation site, on parts including the compressor, reversing valve,
expansion valve, and heat exchanger(s). The Repair / Replacement Labor Allowance is designed to
reduce the cost of repairs. This Repair / Replacement Labor Allowance may not cover the entire labor
fee charged by your dealer / contractor.

Page 1 of 2 XX029

NORTHERN HEAT PUMP, LTD.

A Subsidiary of Electro Industries, Inc.
2150 West River Street, PO Box 538, Monticello, MN 55362
763-295-4138 • 800-922-4138 • fax [phone]
[e-mail]

CONDITIONS AND LIMITATIONS:

1. This warranty is limited to residential, single family dwelling installations only. Any commercial or multi-unit
dwelling installations fall under the Northern Heat Pump Commercial Limited Product Warranty.

2. Northern Heat Pump, LTD. shall not be liable for performance related issues resulting from improper installation,
improper sizing, improper duct or distribution system, or any other installation deficiencies.

3. If at the time of a request for service the or iginal owner cannot provide an original sales receipt or a warranty
card registration then the warranty period for the product will have deemed to begin the date the product is
shipped from the factory and NOT the date of original purchase.

4. The product must have been sold and installed by a licensed electrician, plumbing, or heating contractor.

5. The application and installation of the product must be in compliance with Northern Heat Pump, LTD.
specifications, as stated in the installation and instruction manual, and all state, provincial and federal codes and
statutes. If not, the warranty will be null and void.

6. The purchaser shall have maintained the product in accordance with the manual that accompanies the unit.
Annually, a qualified and licensed contractor must inspect the product to assure it is in proper working condition.

7. All related heating components must be maintained in good operating condition.

8. All lines must be checked to confirm that all condensation drains properly from the unit.

9. Replacement of a product or product part under this limited warranty does not extend the warranty term or
period.

10. Replacement product parts are warranted to be free from defects in material and workmanship for ninety (90)
days from the date of installation. All exclusions, conditions, and limitations expressed in this warranty apply.

11. Before warranty claims will be honored, Northern Heat Pump, LTD. shall have the opportunity to directly, or
through its authorized representative, examine and inspect the alleged defective product or product parts.
Remedies under this warranty are limited to repairing or replacing alleged defective product or product parts.
The decision whether to repair or, in the alternative, replace products or product parts shall be made by Northern
Heat Pump, LTD. or its authorized representative.

THIS WARRANTY DOES NOT COVER:

1. Costs for labor for diagnosis, removal or reinstallation of an alleged defective product or product part,
transportation to Northern Heat Pump, LTD. or Electro Industries, Inc., and any other materials necessary to
perform the exchange, except as stated in this warranty. Replacement material will be invoiced to the distributor
in the usual manner and will be subject to adjustment upon verification of defect.

2. Any product or product part that has been damaged as a result of being improperly serviced or operated,
including, but not limited to, the following: operated during construction phase, with insufficient water or air flow;
allowed to freeze; subjected to flood conditions; subjected to improper voltages or power supplies; operated with
air flow or water conditions and/or fuels or additives which cause unusual deposits or corrosion in or on the
product; chemical or galvanic erosion; improper maintenance or subject to any other abuse or negligence.

3. Any product or product part that has been damaged as a result of natural disasters, including, but not limited to,
lightning, fire, earthquake, hurricanes, tornadoes or floods.

4. Any product or product part that has been damaged as a result of shipment or handling by the freight carrier. It
is the receiver’s responsibility to claim and process freight damage with the carrier.

5. Any product or product part that has been defaced, abused or suffered unusual wear and tear as determined by
Northern Heat Pump, LTD. or its authorized representative.

6. Workmanshi p of any installer of the product or product part. This warranty does not assume any liability of any
nature for unsatisfactory performance caused by improper installation.

7. Transportation charges for any replacement product, product part or component, service calls, normal
maintenance; replacement of fuses, filters, refrigerant, etc.

THESE WARRANTIES DO NOT EXTEND TO ANYONE EXCEPT THE ORIGINAL PURCHASER AT RETAIL AND ONLY WHEN THE PRODUCT IS
IN THE ORIGINAL INSTALLATION SITE. THE REMEDIES SET FORTH HEREIN ARE EXCLUSIVE.

ALL IMPLIED WARRANTIES, INCLUDING WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE, ARE
HEREBY DISCLAIMED WITH RESPECT TO ALL PURCHASERS OR OWNERS. NORTHERN HEAT PUMP, LTD. IS NOT BOUND BY PROMISES
MADE BY OTHERS BEYOND THE TERMS OF THESE WARRANTIES. FAILURE TO RETURN THE WARRANTY CARD SHALL HAVE NO
EFFECT ON THE DISCLAIMER OF THESE IMPLIED WARRANTIES.

ALL EXPRESS WARRANTIES SHALL BE LIMITED TO THE DURATION OF THIS EXPRESS LIMITED WARRANTIES SET FORTH HEREIN AND
EXCLUDE ANY LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES RESULTING FROM THE BREACH THEREOF. SOME STATES
OR PROVINCES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF INCIDENTAL OR CONSEQUENTIAL DAMAGES, SO THE ABOVE
LIMITATIONS OR EXCLUSIONS MAY NOT APPLY. PRODUCTS OR PARTS OF OTHER MANUFACTURERS ATTACHED ARE SPECIFICALLY
EXCLUDED FROM THE WARRANTY.

THIS WARRANTY GIVES YOU SPECIFIC LEGAL RIGHTS, AND YOU MAY HAVE OTHER RIGHTS WHICH VARY UNDER THE LAWS OF EACH
STATE. IF ANY PROVISION OF THIS WARRANTY IS PROHIBITED OR INVALID UNDER APPLICABLE STATE OR PROVINCIAL LAW, THAT
PROVISION SHALL BE INEFFECTIVE TO THE EXTENT OF THE PROHIBITION OR INVALIDITY WITHOUT INVALIDATING THE REMAINDER OF
THE AFFECTED PROVISION OR THE OTHER PROVISIONS OF THIS WARRANTY.

Page 2 of 2 XX029