Two-Stage Split Geothermal Heat Pump Installation & Operating Instructions Model: (RT-SE*) 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 Tested to UL Standards 1995 Information The air coil furnished with this product has been tested and certified with this unit.
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 15 Duct System/A-Coil 17 Mechanical Installation Refrigeration 20 Charging Procedure 22 Superheat and Subcooling 23 Electrical Hookup 28 EZGEO Controller 30 Temperature Sensors, F
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.
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Mechanical Specifications – R410A Two-Stage Compressor RT-SE-040 (3 ton) .65 20°/120° 9/11° 6 lbs. 1 oz. 0.3 0.5 7/8 X 28 7/8 X 27 1/2 275 MODEL Coax & Piping Water Volume – gal Source Temperature °F (min/max) Nominal source differential* ° F (H/C) Factory Charge R410A Static Pressure – Nominal Static Pressure – Design Air Filter Weight– Base Unit Only (lbs) RT-SE-052 (4 ton) 1.1 20°/120° 6/11° 7 lbs. 2 oz. 0.3 0.5 7/8 X 27 1/2 X 37 7/8 320 RT-SE-062 (5 ton) 1.1 20°/120° 6/10° 7 lbs. 2 oz. 0.3 0.
Electrical Data – Single Phase Model 040 052 062 (60 Hz) RLA LRA FLA Loop Pump (Ext) FLA 208/230-1 208/230-1 208/230-1 17.9 27.1 29.7 96 152.9 179.2 .15 .15 .15 4.4 4.4 4.4 Voltage Compressor Desup. Pump Max. Fuse/ HACR Total Min. FLA Ampac. 22.5 31.5 34.3 26.9 38.2 41.7 40 60 70 Total Min. FLA Ampac. Max. Fuse/ HACR 18.6 20.9 22.1 25.0 Electrical Data – Three-Phase Model 040 052 09/11/2014 (60 Hz) RLA LRA FLA Loop Pump (Ext) FLA 200/230-3 200/230-3 14.2 16.
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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.northernheatpump.com for upcoming service schools. 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.
Mechanical Installation Overview This NHP Series unit cannot produce airflow and cannot correct airflow problems inherent within the existing 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.
delivering the CFM required on the nameplate. Especially check the number of registers and 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.
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.
Figure 4 – Pressurized Closed Loop with Flow Center – Typical piping arrangement. Figure 5 – Non-Pressurized Closed Loop with Flow Center – Typical piping diagram.
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 line strainer to prevent debris discharged into the container from being recycled to the system.
Step 10 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.
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.
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.
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.
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; 40-gallon 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.
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.
Coil in Supply Plenum Method Coil in Return Ductwork Method 09/11/2014 19 NI501
Field Installed Thermal Expansion Valve (TEV) – Factory matched air coils are provided with a field installed TEV. Care must be taken when making the brazed connection at the distributor. Too much heat could cause the factory distributor brazing to soften, potentially causing pinhole leaks. Please refer to the diagrams below for installation details.
ST Duct Sensor – See page 31 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. It is the installer’s responsibility to inspect, analyze, and, if necessary, revise the overall ducting system sizing/quality, the furnace blower size/motor, furnace restrictions, return air restrictions, air filter, etc. This involves more than looking at the furnace nameplate.
Line Set Size Information Model 040 052 062 10 Feet Suction Liquid ⅞” ⅜” ⅞” ⅜” ⅞” ⅜” 20 Feet Suction Liquid ⅞” ⅜” ⅞” ⅜” ⅞” ⅜” 30 Feet Suction Liquid ⅞” ⅜” ⅞” ⅜” ⅞” ⅜” See specification chart, page 3, or unit nameplate for factory charge. As stated earlier, this represents the furnished air coil and 10-foot (3 meter) line set. For additional line set length and charge “tweaking” field add as required, see Line Set Information earlier in this section.
Condensate Drain – Typical condensate drain installation, shown below. If there is no nearby floor drain, a condensate drain pump must be used. Condensate Drain Air Coil Vent Slope away from unit Condensate Trap 3” drop Charging Procedure 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.
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.
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.
Unit Operating Conditions – Heat Source Source temp Δ Temp Discharge Suction Discharge Sub cool at pressure at pressure temp TXV 68 deg A-RT at bulb 317-337 161-167 16.3-20.3 80-88 365-385 161-167 16.4-20.4 115-123 411-431 167-173 16.4-20.4 146-154 298-318 148-154 10.8-14.8 100-108 322-342 148-154 11.8-15.8 119-127 358-378 150-156 12.1-16.1 151-159 Suction temp at bulb 30-36 44-50 61-67 40-46 48-54 63-69 GPM Air temp Δ Amps 240 Blower AMPS CFM 3.3-5.3 4.8-6.8 7.2-9.2 2.7-4.7 3.0-5.0 5.1-7.
Unit Operating Conditions – Cool GPM Air temp Δ Dry bulb Amps 240 Blower AMPS CFM Discharge pressure at 80 deg A-RT Discharge temp 9.4-11.4 9.0-11.0 8.5-10.5 6.7-8.7 6.4-8.4 6.1-8.1 6 6 6 6 6 6 20.5-25.5 20.1-25.1 19.2-24.2 18.9-23.9 17.7-22.7 17.4-22.4 6.4-8.5 7.7-9.7 8.6-10.6 3.7-5.6 4.1-6.1 5.2-7.2 1.9 1.8 1.8 1.4 1.6 1.5 921-961 917-947 928-968 782-822 797-837 808-848 219-239 281-301 324-344 205-225 236-256 302-322 121-127 138-144 147-153 106-112 115-121 136-142 8.1-12.1 8.2-12.2 8.5-12.
Pressure/Temperature Conversion Chart for R-410A PRESSURE (PSIG) TEMP °F PRESSURE (PSIG) TEMP °F PRESSURE (PSIG) TEMP °F PRESSURE (PSIG) TEMP °F PRESSURE (PSIG) TEMP °F 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 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.
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.
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.
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.
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.
EZGEO Board Connections 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.
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.
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.
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. If the geo system has been sized to meet 100% of the heating load, it may be desirable to control the strip heat (if equipped) at the thermostat.
Field Setup Overview Your EZGEO-equipped Northern Heat Pump can be set up at your location to fit most any requirements and conditions. This is accomplished with the use of the various dials and switches located on the EZGEO board. It is extremely important the installer properly goes through this section and sets up the various switches to match the installation requirements. Again, refer to HC112 Helps – EZGEO Controller section for further details on these setups.
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 1 = -15° F 2 = -10° F 3 = 0° F 4 = 5° F 5 = 10° F 6 = 20° F 7 = 30° F Using Electric Strip Heat for Supplemental or Emergency Backup Purposes The EZGEO control board has the ability to interface with an Electro Industries WarmFlo Select Plenum Heater (SL1).
Efficiency Setting (Front Panel) This applies to AUX EL module or supplementary heating only, mode B. By adjusting this dial switch the homeowner can boost the ST target temp. A = ST target temperature B = +5° F C = +10° F Gas Furnace CFM See previous page on gas furnace hookup for proper programming of ECM motor for the required CFM output.
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.
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.
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.
Preventative Maintenance Water Coil Maintenance –In closed loop systems, water coil maintenance is generally not needed. However, if a dirty installation or deterioration of the piping has caused debris to accumulate in the system, the water coil should be cleaned using standard cleaning procedures. For open loop systems installed in areas with a high mineral content, it is best to schedule regular periodic maintenance to inspect and clean the coil if necessary.
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.
Troubleshooting/Repair Helps 1. This EZGEO controller contains several interference suppression components, but as an electronic logic 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. 2.
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.
Troubleshooting – General Troubleshooting Guide for Water-to-Air Geo “Heating” Head pressure Subcool Suction pressure Superheat Compressor Amp Draw Air temp differential Source temp differential Low Low Low High Low Low Low Overcharged system High High High Low High High High Low air flow High Low High High High High Low High air flow Low Low High High High Low High Low source flow Low High Low Low Low Low High High source flow High Low High High High High
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