T Therm Geo TST-***, TST-024, TST-036, TST-048, TST-060 Installation & Operating Instructions Manual

Two-Stage Split Geothermal Heat Pump

Installation & Operating Instructions

Model: (TST-***)

Application

 Retrofit existing forced air installations
 Dual Heat – combine this geothermal unit and A-coil with standby

gas or oil furnace

 LMC (Load management control), LMC/INT ready
 Tested to UL Standards 1995

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 may not be tax credit eligible when a coil other than the
furnished coil is used.

For optimum performance an ECM blower is recommended. The CFM airflow required in the
specification table must be matched to the compressor stage 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 offered as an optional item for all TTHERM GEO™
heat pumps. Our exclusive GEO Logic™ control system optimizes the operation of a desuperheater,
operating the systems only when there is adequate energy available to provide heat to the domestic hot
water. However, to maximize the times the desuperheater aides in providing domestic hot water, a hot
water preheat tank is suggested, see Desuperheater section of this manual.

Note – The GEO Logic control board has various required setup adjustments, see Field Setup section.

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

SAFE PLACE FOR FUTURE REFERENCE BY A SERVICE TECHNICIAN.

Important information

Model Number:____________________________
Serial Number:_____________________________
Installing Contractor:________________________

12/03/2012 GI301

Table of Contents

Introduction 1

Product Configurator (GC002) 3

Mechanical Specifications 4

Electrical Data 5

Product Dimensions 6

Installation Requirements 7

Mechanical Installation Overview 8

Mechanical Installation Source Water 11

Desuperheater, Domestic Hot Water 16

Duct System/A-Coil Installation 18

Installing the TXV 19

Mechanical Installation Refrigeration 22

Charging Procedure 23

Superheat and Sub-Cooling 24

Unit Operating Conditions Heat & Cool 25

R-410A Pressure/Temperature Conversion Chart 27

Electrical Hookup 28

GEO Logic Controller 29

Accessories/Options 30

Field Setup Overview 32

Duel Fuel/Utility Control 32

Operation Indicators 34

Power On, Start Up 38

Operational Tips 40

Troubleshooting 41

Preventative Maintenance 44

Drawing GH001 – TT-INT-1 Hookup 46

Drawing GR301 – Refrigerant Hookup 47

Drawing UAW555 – Electrical Diagram 49

Warranty Information – GX002 50

12/03/2012 GI301

Introduction

Geothermal heat pumps are able to heat and cool spaces with efficiencies exceeding 350% by taking advantage
of solar heat stored in the earth’s crust and the earth’s relatively stable temperatures. In the winter time, heat is
moved from the earth into the home and concentrated using a refrigeration system. Since the heat already exists
in the soil, the cost of operation of the geothermal heat pump is, in effect transportation cost for the free heat. In
the summer, heat is removed from the home by reversing the refrigeration process and sending heat back out
into the earth. A geothermal system consists of an earth source (either open loop or earth loop heat exchanger),
a geothermal heat pump containing the refrigeration system and a ductwork system for delivering the
conditioned air to the individual rooms. To learn more about geothermal heating, please visit our web site at
www.tthermgeo.com

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. The GEO Logic control uses a standard, multi-wire heat pump room thermostat to
initiate and terminate all heat/cool functions. There are various temperature sensors, pressure sensors, water
flow switch, etc. which continuously monitor the heat pump system. The interaction of these sensing
components, room thermostat requests, and the various heat pump refrigeration components are all controlled by
an integrated microprocessor system (GEO Logic). The various setup conditions for this microprocessor based
controller determine the application and geo product series. These setups are initially programmed by the
factory, but special PC software and cable are available for reprogramming as required for controller
replacement and/or other options which may apply to the specific installation. See Additional Equipment
Concerns, Field Setup or Programming, Operation Indicators, User Instructions, Control Sequence, and
Troubleshooting sections within this manual for further details on the GEO Logic control.

The utility load control receiver interfaces with the T2-TT-INT-1 which 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. Transport in vertical position only.

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]. TTHERM GEO
Heat Pump provides 4 removable panels for ease of servicing.. 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, part # E2-0122. Water supply should not be hard plumbed directly with copper or PVC
pipe as this could transfer any vibration to living space. Consider using Hose Kit part # L3-0015B to minimize
transferred vibration.

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.

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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.

Warnings, Cautions, and Notes

Throughout this manual there are warnings, cautions and notes containing various levels of important
information. Read all of these items carefully before performing any installation, servicing or troubleshooting
of the system.

Warnings are for any item which MUST be followed and failure to do so could result in serious injury or even

death and/or serious damage to the equipment.

Cautions relate to potentially hazardous situations or important practices which if ignored could cause minor to
moderate injury or cause equipment damage or performance problems.

Notes are used to indicate items of high importance but are not related to a hazardous situation.

Safety Considerations

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T V T - 0 4 8 - 1 C L D X 1 - X X

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

TTHERM GEO (1)

Unit Style (2)

C = Combo

H = Hydronic

S = Split

V = Vertical

Unit Type (3)

A = Single Stage

T = Two Stage

Nominal Tonnage (4, 5, 6)

Voltage Option (7)

Heat Exchanger Option (8)

M = Copper (Load) & Cupronickel

S = Stainless (THT only)

024 = 2-ton
036 = 3-ton

042 = 3.5-ton

048 = 4-ton
060 = 5-ton
072 = 6-ton

096 = 8-ton
120 = 10-ton
144 = 12-ton

1 = 208/230V, 1 Ph
2 = 208/230V, 3 Ph
3 = 460/480V, 3 Ph

C = Copper

N = Cupronickel

(Source)

TTHERM GEO Heat Pump Configurator

Model Number Digits

TVT-048-1CLDX1-XX

Auxiliary kW Option* (13, 14)

05 = 4.8 kW
10 = 9.6 kW
15 = 14.4 kW
20 = 19.2 kW
XX = None

*Can be factory or field installed

Vintage (12)

1

Miscellaneous Kits (11)

A = Soft Start Kit (Installed)
X = None

Desuperheater Option (10)

D = Desuperheater w/Factory

Installed Pump

X = None

Configuration Option (9)

L = Left Return (Standard)*
R = Right Return
C = Split Air Coil
X = N/A or No Split Air Coil

*Left return can be field converted to right return

10/12/2012 GC002

Mechanical Specifications – R410A Two-Stage Compressor

MODEL

TST-024

(2 ton)
Coax & Piping Water Volume – gal .43 .65 1.1 1.1
Source Temperature °F (min/max) 20°/120° 20°/120° 20°/120° 20°/120°
Nominal source differential* ° F (H/C) 3/12° 9/11° 6/11° 6/10°
Factory Charge R410A 3 lbs. 10 oz. 6 lbs. 1 oz. 7 lbs. 2 oz. 7 lbs. 2 oz.
Static Pressure – Nominal 0.3 0.3 0.3 0.3
Static Pressure – Design 0.5 0.5 0.5 0.5
Weight– Base Unit Only (lbs) 240 275 320 320

Model GPM PSID Model GPM PSID Model GPM PSID Model GPM PSID

4 1.2 6 1.8 8 1.3 10 1.9

2-ton

6 2.7 9 2.4 12 2.5 15 3.6
8 3.6 12 4.3 16 4.0 20 5.8

10 5.6

HEAT EXCHANGER PRESSURE DROP TABLE

Water-to-Air (Source Side, Pure Water @ 68° F)

3-ton

15 6.7

PRESSURE DROP MULTIPLIERS

Freeze Point (° F) 20° F 25° F 30° F 35° F 40° F

Pure Water Multiplier 32 1.00 1.00 1.00 1.00 1.00
Methanol 12.5%* Multiplier 16.2 − 1.25 1.21 1.18 1.15
Propylene Glycol 20%* Multiplier 18.4 1.39 1.35 1.31 1.28 1.24
Ethanol 20%* Multiplier 18.1 1.56 1.47 1.42 1.36 1.31

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

2. Stated Btu/h is 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.

*By volume Feet of Head = PSI x 2.31

HEATING – ISO 13256-1 SPECIFICATION – ENERGY STAR

Model Stage

TST-024

TST-036

TST-048

TST-060

FL 8 32.9 850 32 4.05 24.8 850 26 3.56
PL 8 21.8 725 29 21.6 18.5 725 26 3.89
FL 10 42.3 1200 31.8 4.01 33.0 1200 26.5 3.62
PL 10 30.1 1000 27.4 4.35 26.9 1000 24.0 3.90
FL 12 56.0 1500 37 4.02 47.7 1500 29 3.57
PL 12 38.5 1200 31 4.33 37.7 1200 29 3.98
FL 15 70.7 1875 36 4.10 55.7 1875 28 3.59
PL 15 51.9 1480 32 4.22 46.3 1480 30 3.86

Source

GPM

COOLING – ISO 13256-1 SPECIFICATION – ENERGY STAR

Model Stage

TST-024

TST-036

TST-048

TST-060

FL 8 32.8 950 22 19.4 30.6 950 20 16.3
PL 8 23.3 825 21 23.8 22.5 825 22 20.9
FL 10 45.1 1250 20.7 19.7 44.1 1250 19.4 15.8
PL 10 32.2 1050 19.4 22.5 30.5 1050 18.2 18.9
FL 12 63.8 1600 22 19.7 57.4 1600 23 15.4
PL 12 46.9 1275 24 23.5 45.1 1275 23 20.8
FL 15 70.2 2000 23 19.2 63.3 2000 23 14.7
PL 15 50.4 1650 21 23.0 51.3 1650 22 19.7

Source

GPM

GWHP – Ground Water GLHP – Ground Loop
50° F 68° F 32° F/41° F 68° F

Capacity

Btu/h

Blower

CFM

GWHP – Ground Water GLHP – Ground Loop
59° F 80.6° F 77° F/68° F 80.6° F

Capacity

Btu/h

Blower

CFM

4-ton

Temp

Rise

Temp

Drop

TST-036

(3 ton)

20 5.8

COP

EER

Capacity

Btu/h

Capacity

Btu/h

TST-048

(4 ton)

5-ton

Blower

CFM

Blower

CFM

TST-060

(5 ton)

25 8.5

Temp

Rise

Temp

Drop

COP

EER

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Electrical Data – Single Phase

Desup.

Pump

Model

Voltage Compressor

(60 Hz) RLA LRA FLA FLA FLA Ampac.

TST-024 208/230-1 13.1 73.0 .15 4.4 17.7 20.9 40
TST-036 208/230-1 17.9 96 .15 4.4 22.5 26.9 50
TST-048 208/230-1 27.1 152.9 .15 4.4 31.6 38.2 60
TST-060 208/230-1 29.7 179.2 .15 4.4 34.3 41.7 70

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.

TST-024 Not Available

TST-036 200/230-3 14.2 88 .15 4.4 18.6 22.1 30
TST-048 200/230-3 16.5 110.0 .15 4.4 20.9 25.0 40

TST-060 Not Available

Loop

Pump

(Ext)

Total Min.

Max.
Fuse/

HACR

TST Blower CFM Requirements

Model

G Y *Y2

Heat / Cool Heat / Cool
TST-024 Furnace Default 725 / 825 850 / 950
TST-036 Furnace Default 1000 / 1050 1200 / 1250
TST-048 Furnace Default 1200 / 1275 1500 / 1600
TST-060 Furnace Default 1450 / 1650 1875 / 2000

* When the TST unit is installed with a single speed furnace blower, the blower needs to be capable of

delivering the CFM required by Y2

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Product Dimensions

Forced Air Coil – Reference Information

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Installation Requirements

1. All installation work must be performed by trained, qualified contractors or technicians. TTHERM GEO

Heat Pump, sponsors installation and service schools to assist the installer. Contact TTHERM GEO at

[e-mail]

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. TTHERM GEO, 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 dealer training events.

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 TTHERM GEO, 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.

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Mechanical Installation Overview

This TTHERM GEO series unit cannot correct airflow problems inherent within the duct work 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. Inspect and
count supply and return registers for size and number.

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

exists today
geothermal heat pump should be sized to the heat loss of the house. Heat loss and heat gain audits should be
done to determine proper equipment sizing.

Supply plenum – Carefully examine all sides of the plenum. Installing the coil in the supply plenum of a fossil

fuel furnace is the preferred location. If the coil is installed in the return ductwork, the cool air during cooling
could be detrimental to the life of the furnace. Either location would be fine in the case of a fan coil. Verify all
transitions have angles less than 30, the coil is centered within the plenum/ductwork, and there are no odd
shaped angles or odd shaped transitions within the plenum/ductwork.

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.

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. Best practice would include both high and
low return registers.

Blower CFM capacity – The furnace forced air system must have an airflow capacity larger than the minimum
requirement on the TTHERM GEO Series specification sheet (see unit nameplate and/or Mechanical
Specifications). 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. The

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
air coil. If the smallest zone cannot handle the minimum CFM requirements of the heat pump, create a
dump zone and/or allow air flow to bypass to other zones.

a. Existing furnace nameplate

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

b. Blower motor size

- Used only as a minimal guide.

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

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

- Use duct sizing table , or industry

12/03/2012 8 GI301

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 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

Duct Sizing Chart
Acceptable Branch Duct Sizes Acceptable Main or Trunk Duct Sizes
CFM ROUND Rectangular Round Rectangular

100 6” 4x8, 4x6
150 7” 4x10, 5x8, 6x6
200 8” 5x10, 6/8,4x14,7x7
250 9” 6x10, 8x8, 4x16
300 10” 6x14, 8x10, 7x12
350 10” 6x20, 6x16. 9x10
400 12” 6x18, 10x10, 9x12 10” 4x20, 7x10, 6x12, 8x9
450 12” 6x20, 8x14, 9x12, 10x11 10” 5x20, 6x16, 9x10, 8x12
500 10” 10x10,6x8, 8x12, 7x14
600 12” 6x10, 7x18, 8x16, 10x12
800 12” 8x18, 9x15, 10x14, 12x12
1000 14” 10x18, 12x14, 8x24
1200 16” 10x20, 12x18, 14x15
1400 16” 10x25, 12x20, 14x18, 15x16
1600 18” 10x30, 15x18, 14x20
1800 20” 10x35, 15,20, 16x19, 12x30, 14x25
2000 20” 10x40, 12x30, 15x25, 18x20
2200 22” 10x40, 15x25, 20x20
2400 22” 12x40, 16x25, 20x20

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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 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 TTHERM GEO 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 or
trenching equipment approximately six to eight feet (1.8 – 2.4
meters) deep, depending on geographic location and length of pipe used.
Horizontal bored loops are typically installed 15 feet deep.

Figure 1 – Horizontal Closed Loop

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 12ft (3.7 meters)
deep 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 Propylene Glycol should be considered should
damage ever occur to the loop. Consult an IGSHPA or CGC
certified installer for proper lake loop design and installation.
State and local codes apply.

Figure 2 – Vertical Closed Loop

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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. IF YOU LACK EXPERIENCE DESIGNING LOOP FIELDS, 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. TTHERM GEO recommends hose kits for the source water connection points at the heat pump. This
will provide a flexible connection to reduce and isolate vibrations transmitting from the compressor into other parts
of the system. Hose kits also provide P/T ports for monitoring pressure and temperature (see below).

Note

TTHERM GEO heat pumps are factory set for open loop. J11 must be removed for proper operation on an antifreeze
protected closed loop. See figure on page 30 for the location of J11.

Once closed loops are completed, they must be pressure tested to at least 60 PSI to insure integrity. Once
pressure is tested, the 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.

A Flow Meter is an important part of the system. It provides a visual indicator of loop flow in GPM. A flow

meter can be installed on either side of the pump pack, but must be installed per manufacturer recommendations
so it reads accurately.

Non Pressurized Loops require an air separator/stand pipe to eliminate air and to hold enough fluid to

compensate for the expansion and contraction of the loop pipe and fluid. Purge and fill valves should be placed
between the loop manifold valves and the insulated pump pack.

Pressurized Loops do not require an air separator. They require purge and fill ports between the loop manifold

valves and the insulated pump pack. After purging a pressurized loop, it should maintain 45 to 60 psi static
pressure. The Geothermal Loop Pipe stretches under pressure so may need to be pressurized above the desired
pressure several times to achieve the recommended static pressure. Pressurized loops must maintain enough
static pressure to compensate for the expansion and contraction of the loop pipe and fluid.

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

drop. See specification, page 4. 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 – E2-0122.

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

and meet minimum water properties.

 pH < 7.5
 Calcium hardness < 100 PPM
 Iron fouling < 0.2 PPM (Ferrous)

< 0.5 PPM of oxygen

 Hydrogen sulfide (H
 Chloride levels < 20 PPM
 Erosion/clogging 10 PPM, particles
 Filter, if required 800 micron size
 Softened water is recommended along with 2 oz of common house chlorine bleach for every 10 gallons of water.

S) < 0.5 PPM

2

P/T Adapter

Figure 3

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

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

12/03/2012 12 GI301

Antifreeze

When considering the earth loop solution, water quality is very important. TTHERM GEO recommends a
minimum of soft water (not well water) treated with 2 oz. of household chlorine bleach for each 10 gallons of
total volume. TTHERM GEO’s recommended antifreeze concentration is 22% which will yield a freeze
protection of 18° F. This concentration of glycol requires additional additives to protect the system. TTHERM
GEO recommends Enviro-Guard HD propylene glycol for this reason.

Over antifreeze protecting a loop field decreases pumping capacity when the loop gets cold and reduces thermal
transfer. Under protecting a loop field will cause the THERM GEO heat pump to take action protecting itself
from damage. This action will result in a loss of geothermal capacity, and AUX heat may be required to
maintain the temperature in the home.

Table 2 – Approximate Fluid Volume (gal) per 100ft

Pipe Size Volume Pipe Size Volume

Polyethylene

¾” IPS SDR 11 3.02 1” 4.1
1” IPS SDR 11 4.73
1-1/4” IPS SDR 11 7.55 1” 4.5
1-1/2” IPS SDR 11 9.93 1.25” 6.8
2” IPS SDR 11 15.36

Rubber Hose

Copper

Type M

1.25” 6.4

1.5” 9.5

WARNING

PREVENTING FREEZE-UP IS INSTALLER/USER RESPONSIBILITY. DAMAGE CAUSED BY

FREEZE-UP IS NOT COVERED BY WARRANTY.

CAUTION

Softened water is recommended along with 2 oz. of common household chlorine bleach for every
10 gallons of water.

WARNING

NOT ALL GLYCOLS PROVIDE THE SAME LEVEL OF CONCENTRATION. MOST GLYCOLS

DO NOT CONTAIN ENOUGH INHIBITORS FOR THE RECOMMENDED CONCENTRATION

LEVELS.FOR GEOTHERMAL SYSTEMS.

Open Loop – 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 pump’s
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. Constant pressure well pumps need to deliver the GPM
flow rate of the TTHERM GEO heat pump and other possible consecutive demands. 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. Hose kits are installed between the heat pump and ridged plumbing to reduce vibration transfer. Hose
kits have pressure temperature (P/T) plugs placed in the supply and discharge hydrant elbows so that
thermometers or pressure gauges can be inserted into the water stream. On the well water discharge side of the

12/03/2012 13 GI301

heat pump a flow meter is installed to provide a visual indicator of open loop flow in GPM. The water solenoid
valve must be installed to control water flow through the unit. After the water solenoid a flow control valve is
installed to limit maximum flow through the heat pump. The ball valve installed in the leaving water line can be
used to create a small amount of back pressure to quiet the flow control valve if needed. Discharge water
temperature should not drop below 39° at any time during the units operation. Remove handle on the entering
and leaving water ball valves to prevent accidental change of flow.

The solenoid valve is then wired to two leads (brown/yellow and gray) provided. This valve will open when the
unit is running and close when the unit stops. The visual flow meter will allow visual inspection of the flow
requirements, and can 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. 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.

Solenoid Valve Wiring (for Open Loop Systems)

Inside the cabinet, tie-wrapped to the OUT water pipe, are two leads (brn/yel and gray) for direct connection to a
24VAC solenoid.

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. Discharge water should never be lower than 39° F. 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 low pressure, 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).

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Figure 6: Open Loop – Typical piping diagram.

Note

TTHERM GEO heat pumps are factory set for open loop operation.

Open Loop Operation – TTHERM GEO heat pumps are factory set for open loop operation. Open or Closed
loop operation is set with jumper J11 on the left side of the GEO Logic controller. The jumper must be in
place on J11 if the unit is operated on an open loop. The GEO Logic controller protects the heat exchanger

from freezing by causing the compressor to shut down when the leaving water temperature reaches 39° F. The
compressor will remain off for 2 Anti-Cycle-Delays, and the EARTH LOOP FLOW/ SOURCE WATER LIMIT
& HP STAGE 1 LED’s will pulse, while the water runs and warms up. The compressor will then restart again
providing heat until the LWT again reaches 39° F. If this routine continues the heat pump may not be able to
maintain the temperature in the house and the backup heat will come on.
Possible causes would include:

1. Supply water filter that needs cleaning

2. Inadequate water supply

3. Water discharge line that is plugging up

4. Entering water temperature less than 50 degrees

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. A
cupronickel heat exchanger is recommended for open loop applications. If poor water quality is known to exist
in your area a closed loop system may be the best alternative. Water coil cleaning on an open loop system may

be necessary on a regular basis.

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Desuperheater, Domestic Hot Water

General

TTHERM GEO series units may be equipped with a double wall desuperheater and an integrated circulating
pump that can provide Supplemental Domestic hot Water (SDW). This is done by stripping heat from the
superheated gas leaving the compressor.

Fuses – the desuperheater pump is fed from the pump’s 10-amp fuses. The fuses are located on the pump relay
board in the line voltage control box. Note, the desuperheater pump is disabled from the factory. At the

pump relay board top, moving the black/red wire from the “P” tab to the “SWH” tab enables the desuperheater.

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 air pockets from forming at the pump inlet.

WARNING

NEVER USE PEX TUBING WHEN CONNECTING A DESUPERHEATER TO THE DOMESTIC
WATER SYSTEM. NORMAL CYCLING OF THE DESUPERHEATER PUMP CAN CAUSE THE
DISCHARGE WATER TEMPERATURE TO EXCEED THE RATED TEMPERATURE OF THE
PEX CAUSING THE PEX TO FAIL. THIS HAS CAUSED FLOODING IN BASEMENTS.

DESUPERHEATER MUST BE PLUMBED IN COPPER.

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 the air from the desuperheater lines close the ball valve between the desuperheater return,

boiler drain, and the bottom port of the water heater. Open the boiler drain allowing water to flow
through the complete desuperheater circuit purging out the air. When all the air is purged, close the
boiler drain and open the ball valve to the bottom of the water heater.

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

temperatures could become dangerously high.

6. Poor water quality may reduce the effectiveness of the desuperheater pump or 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 will depend on the

desuperheater entering water temperature. The desuperheater will make less hot water when the heat
pump in in cooling mode..

9. For the maximum efficiency from the provided desuperheater module, TTHERM GEO suggests a water
heater preheat tank as shown in Figure 7. The Figure 7A single tank plumbing and application is

There are a number of ways the desuperheater/pump can be plumbed 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).

shown for information only.

 In TTHERM GEO heat pumps the desuperheater is automatically disabled when it is unable to add

additional hot water energy to the water heater or preheat tank. TTHERM GEO units have the
option of the desuperheater operating whenever the compressor runs or it can be disabled in cooling
only by removing jumper J14 on the GEO Logic controller board.

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Figure 7 – Desuperheater Piping, preheat Tank

This is the most effective and efficient arrangement
for high hot water needs. This is also the
recommended method when using a gas water
heater with a desuperheater. The preheat 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 7

Figure 7A – Desuperheater, Single Tank Concept

The water flow is from the top tee, through the desuperheater,
pushing the heated water into the water heater bottom.

The ball valve at the water heater bottom (between drain valve
and tank) is to allow shut-off and an easy method of purging
the desuperheater piping with city/well water forcing through

the system and out the hose bib drain. Note: Both ball valves

must be open whenever the desuperheater electrical source
power wire is plugged into the SWH tab at the control box,
upper right, relay board.

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

Figure 7A

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.

12/03/2012 17 GI301

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 UL listed duct board. 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 the
existing duct system is not designed to handle the increased air flow, larger ductwork should be installed. All
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

TTHERM GEO Split models are sold with a factory matched air coil. You can be assured your heat pump will
perform as designed, meeting or exceeding Energy Star requirements.

Gas, Oil, or Electric Furnace – The heat pump refrigerant air coil may be installed in one of two different

configurations. How you choose to install the air coil is dependent on your structure’s size and space

requirements, personal preferences, and the furnace manufacturer’s recommendations. Refer to your furnace

owner’s manual and installation manual or consult with the furnace manufacturer to make certain the
installation conforms to their requirements.

The air coil provided by TTHERM GEO is relatively large. Although the large physical size of the coil may
present some installation challenges, the size is necessary to achieve optimum system performance.

The air coil may be placed in either the return side or the supply (preferred) side of the heating system. The
following page illustrates two of the mounting methods which may be used.

12/03/2012 18 GI301

Coil in Supply Plenum Method Coil in Return Ductwork Method

Installing the TXV on TTHERM GEO TST Units

1. Be familiar with the following sections in the Installation & Operating Instructions manual:

 Mechanical Installation Refrigeration (line set size and length)
 Charging Procedure (adding or removing refrigeration)
 Superheat and Sub-Cooling (adjusting charge for best performance)

2. Determine if there is enough room to install the TXV inside the plenum. Depending on plenum, it may
be possible on the TST 024 and 036. It is best to plan on installing the TXV outside the plenum on TST
048 and 060. If the TXV is mounted outside the plenum you will need to braze a copper pipe extension
to the refrigerant distributor cone and route it outside the plenum.

Note: Check TXV installation illustrations in this manual and those packaged with it to be sure the TXV
is installed in an orientation that will allow it to work properly.

All brazing will need to be done at the same time so a 2-3 psi nitrogen purge can flow through the line set,
TXV, and coil while brazing. Low silver copper braze alloy shall be used on all copper to copper brazed
connection points. A high silver brazing material like Harris Safety-Silv® 45FC
used when brazing the Brass Distributer cone to the copper pipe. Be careful to keep the temperature
sensitive components (TXV) cool during the brazing process.

3. Position the TXV and construct a copper refrigerant line from the out port on the TXV to the distributor
cone of the A-coil.

Note: Remember the capillary tube must extend far enough for proper installation of the bulb. The bulb
must be located past the last refrigerant circuit getting on the manifold and in a horizontal plane. The
bulb must be in contact with the horizontal line for it entire length, and positioned at the 9 or 3 o’clock
position on the pipe. Remember do not attach the TXV bulb to the suction line until all brazing is
complete and the line has cooled.

– (45% silver) should be

12/03/2012 19 GI301

12/03/2012 20 GI301

4. Determine the location of the TXV bulb on the suction line of the A-coil or the line set. Locate a point
on top 2-4” from the bulb and towards the compressor. Drill a ¼” hole to accept the equalizer line from
the TXV. Deburr the hole and clear the pipe of all shavings and debris. If the drilled hole is in the
suction line, install the suction line of the line set to the manifold.

5. Fabricate a ¼” copper line to connect the TXV equalizer port to the hole drilled in the suction line of the
manifold or line set. Either swedge the ¼” tube or use a ¼” coupler to attach one end of the ¼” line to
the TXV. Insert the other end of the ¼” equalizer line into the hole drilled in the suction line just far
enough so that it can be brazed without the chance of brazing the ¼” line shut.

6. Attach the liquid line from the line set to the IN port of the TXV.

7. Double check to be sure all joints to be brazed are properly positioned and seated in their fitting.

8. Remove the Schrader core from both service ports. Connect nitrogen tank to one of the service ports.
Flow 2-3 psi of nitrogen through the line set and coil while brazing.

9. Braze and inspect all joints protecting temperature sensitive parts (TXV, brass distributor cone, service
ports and valves on the unit).

10. Reinstall the Schrader cores in both service ports after lines have cooled.

11. Pressure test the line set and A-coil assembly, using nitrogen and a trace gas if necessary.

12. If no leaks are found release the nitrogen and evacuate the line set and A-coil assembly to 500 microns
or less.

13. While the vacuum pump is running, install the TXV bulb, insulate the TXV, line set from TXV to
plenum if mounted outside, and double insulate the TXV bulb and adjacent suction line.

14. You are now ready to follow the instructions in the Charging Procedure and Superheat and Sub-Cooling
section of the Installation and Operating Manual

ST Duct Sensor – must be installed in the air stream 24” beyond the coil.

Airflow (CFM) – As listed on the unit nameplate and the specification table the minimum CFM flowing

through the coil must be appropriate to the compressor stage. 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. 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.

12/03/2012 21 GI301

Mechanical Installation Refrigeration

Overview

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

unit. The charge may need 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.

 Provisions and plenum arrangements must be made to accommodate the 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 provided. 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 chance of compressor vibration transmitting into

other areas of the building. When hangers are necessary; use hangers that incorporate isolation sleeves.

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 are required. During the brazing process, 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 service valves have been opened, the final charge may need to be fine tuned based upon the sub-

cooling and superheat chart.

12/03/2012 22 GI301

t

p

Line Set Size Information

Model

10 Feet 20 Feet 30 Feet

Suction Liquid Suction Liquid Suction Liquid

TST-024 ¾” ⅜” ¾” ⅜” ¾” ⅜”
TST-036 ⅞” ⅜” ⅞” ⅜” ⅞” ⅜”
TST-048 ⅞” ⅜” ⅞” ⅜” ⅞” ⅜”
TST-060 ⅞” ⅜” ⅞” ½” ⅞” ½”

See specification chart, page 4, 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.

Air

Coil

Condensate Drain

Ven

Condensate Trap
3” dro

Slope away from
unit

Charging Procedure

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

pressurize 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 and air coil 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 line set and air coil through both service ports to prevent false
readings on the gauge because of pressure drop through service ports.

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 sub-cooling.
Keep adding refrigerant until the unit meets the superheat and sub-cooling values on Unit Operating Conditions
chart.

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Superheat and Sub-Cooling

Comments

1. This is a two TXV system – the heating TXV is internal to the main cabinet at the water coil refrigerant
entrance and the cooling TXV is located on the plenum air coil at the air coil liquid entrance.

2. Begin in heating and check Superheat and Subcool 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 26.

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 TXV 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.

Determining Sub-Cooling

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 sub-cooling ranges at specific
enter water conditions.

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Unit Operating Conditions – Heat

Model Stage

Source

Temp

Source temp Δ GPM Air temp Δ Amps 240

Blower

AMPS

CFM

Discharge

pressure at

68 deg A-RT

Discharge

temp

Sub cool at

TXV

Suction

pressure

at bulb

Suction
temp at

bulb

Super- heat

at bulb

2 32 3.3-5.3 6 26-32 8.6-9.6 1.5 840-880 317-337 161-167 16.3-20.3 80-88 30-36 10.1-14.1
2 50 4.8-6.8 6 34-39 9.7-10.7 1.5 850-890 365-385 161-167 16.4-20.4 115-123 44-50 8.0-12.0
2 68 7.2-9.2 6 41-46 11.0-12.0 1.4 840-880 411-431 167-173 16.4-20.4 146-154 61-67 9.3-13.1

1 41 2.7-4.7 6 22-27 5.8-6.8 1.0 690-730 298-318 148-154 10.8-14.8 100-108 40-46 7.6-11.6
1 50 3.0-5.0 6 27-32 6.1-7.1 1.0 690-730 322-342 148-154 11.8-15.8 119-127 48-54 7.7-11.7
1 68 5.1-7.1 6 33-38 6.4-7.4 1.0 690-730 358-378 150-156 12.1-16.1 151-159 63-69 8.4-12.4

2 32 4.0-6.0 9 24-29 11.4-12.4 2.4 1190-1230 305-325 133-139 15.4-19.4 79-88 31-37 10.9-14.9
2 50 5.4-7.4 9 31-36 12.9-13.9 2.3 1200-1240 345-365 136-142 17.7-21.7 19-117 46-50 9.6-13.6
2 68 8.0-10.0 9 41-46 14.4-15.4 2.2 1190-1230 404-424 143-149 15.5-19.5 148-156 62-69 9.7-13.7
1 41 3.3-5.3 9 24-29 8.1-9.1 1.6 980-1020 298-318 131-137 13.5-17.5 98-106 40-46 8.7-12.7
1 50 3.7-5.7 9 27-32 8.4-9.4 1.6 990-1030 315-335 128-134 13.0-17.0 114-122 45-51 6.9-10.9
1 68 5.6-7.6 9 33-38 9.0-10.0 1.6 970-1010 354-374 133-139 15.1-19.1 150-158 61-68 8.1-12.1

2 32 3.4-7.4 12 26-34 17.0-23.0 3.0 1487-1567 313-353 165-175 14-22 71-91 28-34 7.4-15.4
2 50 5.6-9..6 12 35-43 19.5-25.5 3.0 1485-1565 360-400 167-176 17.8-25.8 106-126 43-49 4.5-12.5
1 41 3.0-7.0 12 26-34 11.4-17.4 2.1 1177-1257 304-344 153-163 8.4-16.4 92-112 39-45 6.1-14.1
1 50 3.4-7.4 12 30-38 11.9-17.9 2.1 1188-1268 325-365 153-163 10.6-18.6 109-129 46-52 5.7-13.7

2 32 3.9-5.9 15 26-31 20.4-21.4 4.7 1850-1890 317-337 161-167 15.3-19.3 73-82 30-36 12.9-16.9
2 50 6.0-8.0 15 34-41 23.0-24.0 4.7 1850-1890 363-383 160-166 17.3-21.3 103-111 43-50 10.3-14.3
2 68 8.0-10.0 15 40-45 25.2-26.2 4.7 1860-1900 408-428 165-171 18.2-22.2 132-140 56-62 10.7-14.7
1 41 4.2-6.2 15 25-30 15.9-16.9 3.6 1590-1630 310-330 153-159 11.8-15.8 95-103 38-45 9.0-13.0
1 50 4.3-6.3 15 28-33 16.3-17.3 3.6 1600-1640 325-345 152-158 12.5-16.5 110-118 45-52 9.1-13.1
1 68 6.4-8.4 15 35-40 17.5-18.5 3.6 1620-1660 367-387 151-157 12.5-16.5 146-154 60-66 7.9-11.9

TST-048

TST-060

TST-024

TST-036

NOTE: 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.

12/03/2012 26 GI301

Unit Operating Conditions – Cool

Model Stage

Source

Temp

Source temp

∆

GPM

Air temp Δ

Dry bulb

Amps 240

Blower

AMPS

CFM

Discharge

pressure at 80

deg A-RT

Discharge

temp

Sub-cool at

TXV

Suction

pressure at

bulb

Suction
temp at

bulb

Super-heat

at bulb

2 59 9.4-11.4 6 20.5-25.5 6.4-8.5 1.9 921-961 219-239 121-127 8.1-12.1 129-136 58-64 14.2-18.2
2 77 9.0-11.0 6 20.1-25.1 7.7-9.7 1.8 917-947 281-301 138-144 8.2-12.2 132-142 60-66 13.8-17.8
2 86 8.5-10.5 6 19.2-24.2 8.6-10.6 1.8 928-968 324-344 147-153 8.5-12.5 136-146 60-66 12.4-16.4
1 59 6.7-8.7 6 18.9-23.9 3.7-5.6 1.4 782-822 205-225 106-112 3.5-7.5 138-148 61-67 12.2-16.2
1 68 6.4-8.4 6 17.7-22.7 4.1-6.1 1.6 797-837 236-256 115-121 3.6-7.6 141-151 62-67 11.8-15.8
1 86 6.1-8.1 6 17.4-22.4 5.2-7.2 1.5 808-848 302-322 136-142 4.5-8.5 145-155 63-39 11.0-15.0

2 59 11.2-13.2 9 22.5-27.5 10.1-12.1 2.5 1234-1274 252-272 122-128 18.1-22.1 134-144 62-68 14.6-18.6
2 77 10.5-12.5 9 21.8-26.8 12.2-14.2 2.5 1220-1260 321-341 132-138 17.2-21.2 139-149 61-67 11.2-15.2
2 86 9.6-11.6 9 21.1-26.1 13.2-15.2 2.6 1229-1269 363-383 142-148 18.8-22.8 137-147 59-65 10.8-14.8
1 59 7.8-9.8 9 21.1-26.1 5.8-7.8 2.1 1021-1061 233-253 108-114 14.7-18.7 143-153 63-69 12.2-16.2
1 68 7.6-9.6 9 19.2-24.2 6.6-8.6 2.2 1052-1092 267-287 115-121 13.7-17.7 145-155 61-67 9.6-13.6
1 86 6.7-8.7 9 18.6-23.6 8.4-10.4 2.1 1063-1103 334-354 131-137 14.6-20.6 147-157 62-68 9.2-13.2

2 59 11.9-15.9 12 21.2-29.2 13.9-19.9 3.8 1562-1642 244-284 125-135 18.1-26.1 124-144 57-63 10.5-18.5
2 77 11.3-15.3 12 19.4-27.4 16.7-22.7 3.7 1580-1660 308-348 142-152 17.3-25.3 128-148 58-64 9.6-17.6
1 59 8.2-12.2 12 20.7-28.7 6.7-12.7 2.0 1181-1241 219-259 111-121 12.9-20.9 131-151 60-66 9.7-17.7
1 68 41133.0 12 19.9-27.9 7.8-13.8 2.0 1164-1244 249-289 123-133 12.9-20.9 132-152 60-66 8.8-16.8

2 59 11.7-13.7 15 22.6-27.6 17.5-19.5 5.2 1814-1854 257-277 124-130 19.8-23.8 120-130 53-59 11.9-15.9
2 77 10.7-12.7 15 21.3-26.3 20.3-22.3 5.2 1823-1863 321-341 140-146 18.1-22.1 122-132 53-59 11.4-15.4
2 86 9.9-11.9 15 21.2-26.2 22.1-24.1 5.1 1812-1852 358-378 151-157 18.4-22.4 122-132 53-59 12.5-16.5
1 59 7.3-9.3 15 21.2-26.2 9.8-11.8 2.8 1373-1413 218-238 116-120 14.0-18.0 136-146 57-63 9.5-13.5
1 68 8.2-10.2 15 21.9-26.9 11.9-13.9 3.0 1398-1438 261-261 123-129 13.7-17.7 130-140 55-61 9.4-13.4
1 86 7.5-9.5 15 20.6-25.6 14.7-16.7 2.9 1387-1437 327-347 143-149 13.6-17.6 136-146 57-63 9.3-13.3

TST-024

TST-048

TST-060

TST-036

NOTE: 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.

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

12/03/2012 27 GI301

Electrical Installation

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 field supply is 208V the tap on the transformer primary winding must be switched from orange

tor red. See the wiring diagram.

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 – control box, upper right, is the pump relay board with field terminal block connection for the

source loop pump station and where applicable the 2

nd

loop pump (load pump output applies only to water to

water series). These outputs are controlled by GEO Logic, but protected with 10-amp fusing.

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.

12/03/2012 28 GI301

GEO Logic™ Controller

GEO Logic Features

The GEO Logic controller has a control strategy that will maximize the capabilities of the heat pump. The LED
information lights on the front will communicate the THERM GEO’s current stage and mode of operation.
GEO Logic also has the capability to communicate diagnostic information so it can be kept running at maximum
efficiency.

Application

The GEO Logic controller is standard on all TTHERM GEO Heat Pump models. The GEO Logic controller is
designed to run under different operating “modes”.

 Basic water to air packaged unit

 Basic water to air packaged unit with Electro Industries’ WarmFlo

 Basic water to air packaged unit with added gas furnace using the T2-TT-INT-1 option

 Basic water to air split unit, using the T2-TT-INT-1 option

 Basic water to water packaged unit

Abbreviations used in the section:

ACD – anti-cycle delay timer (factory set @ 3minutes)
AUX – strip heat module, an option installed within the TTHERM GEO cabinet
CC – compressor contactor
CDT – compressor refrigerant discharge temperature
CFM – cubic feet per minute airflow
COMP – compressor
CSL – compressor safety logic subset, separate processor and power supply which monitors and controls the

major compressor protection sensors
DDT – desuperheater refrigerant discharge temperature
ECM - electronically commutated blower motor
Hard Lockout – the CSL has completed a sequence and shut down the compressor. The GEO Logic processes

this status, forwards this status to various connections/indicators lights, and provides AUX backup heat

from stat-Y. This operating state is only cleared by a power reset.
HUM – a stat terminal relating to a humidistat function to increase cooling dehumidification. Factory default for

this terminal is at 24 volts, assumes the stat is normally high and goes low when dehumidification is

desired. Thus there is a peg jumper (J12) which must be removed when a stat HUM wire is connected.

This function is only available on the TVA & TVT units.
INT – the monitor line from the LMC/SB option box indicating a declared interrupt.
LED – light emitting diode
LMC – utility load management control (off-peak = NC), identifying the device with blue and blu/wht 2-wire

connection to interrupt electric usage and/or transfer the heating energy function to a standard gas/oil

thermostat type terminal block.
LWT – source leaving water temperature
RPM – revolutions per minute
SB – standby furnace or equivalent heating unit or mode
Soft Lockout – reference CSL limit conditions, there is a set number of retries once “lockout” has been declared.

When the system is operating in this retry range, for communication purposes this is considered soft

lockout.
ST- supply temperature (output air or water) sensor
STG – stage 1, 2 or 3 of electric heat

®

strip heat

CAUTION

Type of room thermostat required

Use a heat pump thermostat with an “O” signal for cooling, and a compressor signal “Y” for heat/cool. The
thermostat needs to provide a “Y2” signal if the unit is equipped with two compressor stages. The
thermostat will also need to supply a “W2” signal for aux heat which may be electric or gas.

12/03/2012 29 GI301

NOTE

If a programmable thermostat is used, it is recommended that the program be set to disable. In

programmable mode, the heating system must be oversized in order to recover from the setback. Since heat
pumps are not typically oversized, they require a longer time to recover from the setback period. During
this recovery period the system will likely call for electric heat to decrease the recovery time, resulting in
lower efficiency. A closed loop performs best when the connected heat pump is allowed to cycle on and
off. This cycling allows the closed loop to absorb more heat from the earth and move it into the home.

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 TTHERM GEO 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 (thermostat) you are installing.

Accessories/Options

TTHERM GEO Alarm T2-R-AL-FD-1
Fuse – source loop pump, 10A T9-UFUSE6670
Thermostat Simulator w/ACD override T2-TT-CS-1
PC Software and Cable ( Windows 95 - 7) T2-ET-SOFT-GL1
Hand Held GEO Logic scan tool T2-_________
30” x 38” Air Pad E2-0122

Part Number

12/03/2012 30 GI301

Figure 8 GEO Logic Board Assignment

WARNING

ANY CHANGES MADE TO SWITCH SETTIINGS, JUMPERS, OR ACCESSORIES
CONNECTED TO THE GEO LOGIC CONTROLLER WILL REQUIRE THE GEO LOGIC

CONTROLLER TO BE POWER CYCLED FOR THE CHANGES TO TAKE EFFECT.

12/03/2012 31 GI301

Field Setup Overview

Thermostat

Connect all the standard heat pump connections. This will require 10 conductor thermostat cable.
This thermostat wire should be routed through the knockout on the left side of the cabinet by the box containing
the GEO Logic controller using the proper strain relief.
Terminals are as follows:
E – emergency/auxiliary heat
R – 24 volt ac power from TTERM GEO heat pump
G – constant fan
O – Activates the reversing valve for cooling mode

st

stage compressor

Y – 1
W2- starts the auxiliary heat sequence of operation

nd

Y2 – 2

stage compressor
C/X – 24 volt ac common from TTHERM GEO heat pump
L – Hard Lockout signal from TTHERM GEO heat pump
HUM – stat terminal relating to a thermostat with humidistat function (not functional on TST models).

T2-TT-INT-1 – (dual fuel/utility control this is a separately mounted box with pigtail cable that plugs into

the main GEO Logic controller.

Applies to dual heat/dual fuel application and Split models. The enclosure is 6”W x 10”L x 3”D with 8­foot cable for plugging into GeoLogic board (J4, top center). In addition to the traditional Utility
Receiver 2 blue wires, there are 5 LED’s (R, status-LMC/-L/-E, backup heat, blower-Y, stat-W2). This
module also has the basic 6-position gas/oil furnace terminal block (R, W, G, C, Y, Y2). This design
includes proper 24-volt isolation from the gas furnace transformer R.

See T2-TT-INT-1 installation instructions in the box placed inside cabinet.

1. The electrical diagram in the back of this manual is very self-explanatory.

2. This interface module will not operate without 24 volts from the furnace or fan coil.

3. Pay close attention to the color of the wires and where each one is connected.

4. The wires and connector to connect the interface module to the GEO Logic controller are located inside the

interface module cabinet.

5. Thermostat wire containing 6 wires is needed to connect the interface module to a furnace or fan coil.

6. The utility load control is connected across the Blue & Blue/White wires. These wires are connected together

with a wire nut. The utility control relay will take the place of the wire nut.

NOTE

Temperature Sensors

Temperature sensors installed in TTHERM GEO heat pumps are NOT thermisters. They are digital devices

calibrated at the manufacturer. They are polarity sensitive. Be sure to connect the red and white wires in their
correct shared terminals. The black wire is the data stream wire and will have its own screw terminal.

WARNING

THE DUCT SENSOR (ST) MUST BE INSTALLED ON ALL FORCED AIR MODELS.
Duct Sensor (ST) – install in the furnace supply air plenum, at least 24 inches (61cm) above the top of the

furnace (airflow inches). The ST sensor does not have an end cap; the small black electronic part just within the
tube end is the actual temperature sensor. It is desirable for the air coming out of the coil to pass as close as
possible to the black tip without warm-up or dampening delay. For best results, the sensor should be positioned
in the maximum air stream.

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.
 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” (30.5cm) away from any line voltage wiring, romex, etc.
 If you must cross line voltage, the lines must cross at a 90 angle.

12/03/2012 32 GI301

 Tip – when working with the plug-in sensor terminal block and a cable (example, ST), start with

black wire. This can help hold the cable when working with the double white and red’s.

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

Open or Closed Loop Jumper

NOTE

Open or Closed Loop Jumper J11 – This jumper comes from the factory shorting the pins and

Open Loop Water Solenoid Connections

The optional water solenoid 24 volt connections are located inside the cabinet near the source water out
connection. The cabinet has a knock out provided for the brown/yellow and gray wires.

is configured for open loop. For closed loop operation jumper J11 must be disabled/open.

Desuperheater

Observe the pump relay board, high voltage compartment upper right corner, there is tagged black/red wire
connected to a “parking” tab just above the row of small relays. In this position the desuperheater pump is not
active and this position acts as a “manually operated switch” for the desuperheater pump. After installation is
complete with proper water circulation from the water heater, this tagged wire can be moved from its P tab to
the SWH tab (should be open from the factory) outlined by a rectangular box. Anytime in the future there is a
need to deactivate the desuperheater pump, again pull off this tagged wire and move it to the P tab (directly
above the row of small relays).

The desuperheater will operate under GEO Logic control in both heat and cool modes with
jumper J14

When plumbing the desuperheater, refer to the diagrams on page 16.

on. If jumper J14 is removed the desuperheater will only operate in heat mode.

WARNING

NEVER USE PEX TUBING WHEN CONNECTING A DESUPERHEATER TO THE DOMESTIC WATER
SYSTEM. NORMAL CYCLING OF THE DESUPERHEATER PUMP CAN CAUSE THE DISCHARGE WATER
TEMPERATURE TO EXCEED THE RATED TEMPERATURE OF THE PEX CAUSING THE PEX TO FAIL.
THIS HAS CAUSED FLOODING IN BASEMENTS.

DESUPERHEATER MUST BE PLUMBED IN COPPER.

WARNING

THE DESUPERHEATER MOTOR SHALL NEVER BE ACTIVATED OR RUN UNTIL THERE IS PROPER
CONNECTION TO THE WATER HEATER AND THE AIR HAS BEEN PURGED OUT OF THIS WATER
CONNECTION. DAMAGE WILL RESULT TO THE DESUPERHEATER PUMP IF IT IS RAN DRY.

Grounding

The 24 volt transformer and Geo Logic board common are connected to the equipment ground terminal.
The high voltage source ground (green) must be connected to the equipment ground terminal.

High Voltage Wiring

The TTHERM GEO heat pumps will require at least one high voltage circuit. The Electrical Data tables on page
5 will provide the information necessary to determine the correct size circuit. The high voltage wires should be
routed through the knockout(s) on the right side of the cabinet and fed straight through into the high voltage
section of the control box.

WARNING

HIGH VOLTAGE WIRES SHALL NEVER BE ROUTED THROUGH THE LOW VOLTAGE COMPARTMENT.

12/03/2012 33 GI301

Operational Indicators

POWER ON (Green LED)

ON Solid – Normal
Pulsing – Bad sensor

1 blinks every 2 seconds - Bad ST sensor
2 blinks every 2 seconds - Bad DDT sensor
3 blinks every 2 seconds - Bad LWT sensor
4 blinks every 2 seconds - Bad CDT sensor

HP STAGE 1 (Bicolor LED)

RED - Heating Mode:

ON Solid - Stat Y input is active.
Pulsing - ACD is timing. (anti-cycle delay timer)

Normal compressor delay at start up or a delay to allow refrigerant pressures or
temperature sensors to reach a normal starting pressure or operating temperature range.

GREEN - Cooling Mode:

ON Solid - Stat Y input is active.
Pulsing - ACD is timing. (anti-cycle delay timer)

Normal compressor delay at start up or a delay to allow refrigerant pressures or
temperature sensors to reach a normal starting pressure or operating temperature range.

HP STAGE 2 (Yellow LED)

ON Solid - HP-Y2 is running.

AUX HEAT (Yellow LED) (Not used on the TST units)

ON Solid - AUX is ON.

Comment – three AUX LEDs on the inside of the board indicate how many stages of electric
heat have been activated.

Pulsing - Open safety limit.

The primary high temp limit has opened in the electric heat module.

Front Panel LEDs:

12/03/2012 34 GI301

EARTH LOOP FLOW/SOURCE WATER LIMIT (Red LED)

ON Solid - No source flow lockout
Pulsing:

Open Loop - LWT < 'Open Loop, Source LWT Warning (Heat)'
Closed Loop - LWT < 'Closed Loop, Source LWT Warning (Heat)'.

If LWT is less than this value a shutdown with 2 x ACD’s (6 min) is performed
This will NOT cause a hard lockout; it is simply a warning and a pause in the system
for possible system correction or notification for further service action.

LO PRESSURE/LOW TEMP LIMIT (Red LED)

ON Solid - Low pressure lockout
Pulsing – Load side discharge temp. too cold.

Air - ST < 'Lo Press. Air ST Warning (Cool)'

If ST is less than this value a shutdown with 2 x ACD’s (6 min) is performed. This will
NOT cause a hard lockout; it is simply a warning and a pause in the system for possible
system correction or notification for further service action.

HI PRESSURE/HIGH TEMP LIMIT (Red LED)

ON Solid - High pressure lockout
Pulsing – Load side discharge temp. too hot.

Air - ST > 'Hi Press. Air ST Warning (Heat)'

If ST is greater than this value a shutdown with 2 x ACD’s (6 min) is performed. This
will NOT cause a hard lockout; it is simply a warning and a pause in the system for
possible system correction or notification for further service action.

HOT GAS/BLOWER FAILURE (Red LED)

ON Solid - CDT > 'Compressor Discharge Temperature Lockout

If CDT is greater than this value a soft lockout with 2 x ACD’s (6 min) is performed.
The 4th time this happens in the same heating or cooling cycle the unit will go into a hard
lockout.

Pulsing - Hard Lockout caused by ECM fault (not used on the TST models)

ECM fault codes are read from ECM STATUS & ECM RPM LED’s on the inside of this board
(see information below)

12/03/2012 35 GI301

Back of Circuit Board – LED’s

STG 1-3 (Red LED’s)
(not used on TST models)

CC (Green LED)

ON when the compressor contactor (CC) is ON.

ECM STATUS (Green LED)

(not used on TST models)

ECM RPM (Yellow LED)

(not used on TST models)

FAULT COUNT (Red LED, left side next to model size dial switch)

Normally OFF

Counts out a code for the current fault (see Fault Codes)

PROGRAM FAULT CODES (FAULT COUNT LED):

1 Pulse = Lost Source Flow
2 Pulses = Refrigerant High Pressure Limit (550 psi)
3 Pulses = Refrigerant Low Pressure Limit (40 psi)
4 Pulses = Loss of refrigerant charge
5 Pulses = Under Voltage detect (source voltage less than 195 volts)
6 Pulses = CDT Safety Limit (230 degrees)
7 Pulses = See ECM Motor Fault section (TVA & TVT units only)
8 Pulses = Lost load water flow (THA & THT units only)
9 Pulses = Leaving source water or load freeze limit

12/03/2012 36 GI301

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. Do not reset a well water
system in the heating mode without first verifying water flow.

WARNING

DO NOT RESET THE SYSTEM MORE THAN ONCE
REPEATED RESETTING OF THE HARD LOCKOUT CAN CAUSE SERIOUS DAMAGE. IF SAME
LOCKOUT OCCURS CONTACT YOUR SERVICE DEALER IMMEDIATELY.

User Visual Warnings

Various front panel LED’s have pulsing indication when certain key temperature parameters reach a point where
system corrective action is advised. GEO Logic has default points where the manufacturer feels notification
should be made. When any one of these temperature points is reached the compressor is shut down for 2 x
ACD’s (6 min.). At the end of this shutdown delay the compressor will again be activated as an automatic reset
type function. This does not lead to a lockout, it is simply a warning and a pause in the system for possible
system correction or notification for further service action.

These LED’s will be pulsing during the 2 x ACD (6 min.) shutdown/auto reset cycle.

Function Sensor

Default FA

Values

Lo pressure ST 35° √ 3°

Hi pressure ST 110° √ 5°

Loop temp. LWT 39° open, 20° closed √ -

AUX HL Internal Fixed √ 20°

Trip Point

Increase Decrease

Differential

12/03/2012 37 GI301

Power On Startup

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

1. All plumbing and ductwork to the heat pump and furnace is complete and operational.

2. Low voltage wiring of the thermostat, LMC/INT, furnace/fan coil and any additional control wiring is

complete.

3. Set thermostat to the OFF position.

4. All high voltage wiring is correct including disconnect and wire sizes.

5. Turn on the high voltage to furnace and fan coil.

6. 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.

7. You may now apply power to the unit. A 3 minute delay on power up is programmed into the GEO

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

8. Verify source water flow – specification page.

 Open loop systems - manually open water solenoid valve on well system to check flow.

 Closed loop systems – operate earth loop pumps to verify flow of antifreeze protected loop

fluid.

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. It is during these steps the information is

collected to complete the ‘Forced Air Heat Pump Operational Statistics’ sheet. This sheet is the top page of

this manual. It should be removed, filled out and kept with the manual for future reference.

1. Do not connect refrigerant gauges to this unit unless the data collected indicates there is a problem.

2. Place the thermostat to the “HEAT” position. Turn the thermostat up to activate a 1

st

stage call for heat.

 Pumps have an initial purge cycle, then compressor and furnace/fan coil blower will start.
 Check and record source water flow rate in GPM, see specification chart at the beginning of this

manual for minimum water flow requirement.

 Check and record antifreeze protection level.

3. After the unit has run for about 3 minutes.

 Check and record the source side supply and return water temperatures.
 Check and record the supply and return air temperatures.
 Check and record the running voltage.
 Check and record the total amp draw.
 Check and record the compressor amp draw.

4. Raise the thermostat only enough to call 2

nd

stage. Again wait 3 minutes.

 Check and record the source side supply and return water temperatures.
 Check and record the supply and return air temperatures.
 Check and record the running voltage.
 Check and record the total amp draw.
 Check and record the compressor amp draw.

5. Raise the thermostat to call for AUX heat. Wait 3 minutes.

 In the case of a fossil fuel furnace, did the geo shut down and the furnace start.
 Check and record the supply and return air temperatures

12/03/2012 38 GI301

6. Turn the thermostat to the off position.

7. Place the thermostat in the “COOL” position. Turn the thermostat down to activate a 1

cooling. The compressor will start after a 3 minute ACD period from its last shutdown.

 The compressor and furnace/fan coil blower will start.

8. After the unit has run about 3 minutes.

 Check and record the source side supply and return water temperatures.
 Check and record the supply and return air temperatures.
 Check and record the running voltage.
 Check and record the total amp draw.
 Check and record the compressor amp draw.

9. Raise the thermostat only enough to call 2

nd

stage (if applicable)

 Check and record the source side supply and return water temperatures.
 Check and record the supply and return air temperatures.
 Check and record the running voltage.
 Check and record the total amp draw.
 Check and record the compressor amp draw.

10. Be sure all operational data has been collected and recorded on the ‘FA Heat Pump Operational

Statistics’ sheet.

11. Reset the thermostat to normal mode and temperature settings for the season.

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

st

stage call for

12/03/2012 39 GI301

Operational Tips

GEO Logic - The GEO Logic board performs the functions controlling the compressor operation, system

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

Review Operational Indicator section of this manual before proceeding.

Pump/Blower Purge – a Y-stat input starts the blower motor, loop source pump, open loop solenoid, and

desuperheater pump. The stat-Y action input to CSL is delayed by 5 seconds. These four items allow for
“circulation” before the compressor is turned on. The blower motor has a 45-second turn on ramp thus it will not
be noticeable during this 5-second start purge.

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 2 X ACD (6 minutes) expires and both
pressure switches are closed. If the GEO Logic controller experiences three high pressure, low pressure soft
lockouts in a single thermostat call period, it will hard lock out the compressor. During both hard and soft
lockouts the fault codes are displayed.

The flow switch has a bypass timer in which the GEO Logic board will ignore an open flow switch for the first
15 seconds. If the flow switch opens the GEO Logic controller will de-energize the compressor and initiate a
single soft lockout. If the GEO Logic controller experiences a second flow switch fault during a single
thermostat call period, it will hard lock out the compressor.

NOTE

This is a fluid flow switch; it is not a GPM sensor for determining adequate flow. It is only an indicator, and
cannot be used to determine sufficient flow.

A manual reset of power will be required to reset any hard lockout condition.

At stat-Y end, loop source pump, desuperheater pump, and solenoid turn off immediately.

Problems that could cause a lockout situation include:

1. Source water flow problems

2. Hydronic water flow problems

3. Internal heat pump operation problems

4. Excessive cold water temperature conditions, source and load

5. Excessive hot water temperature conditions , source and load

The GEO Logic control has a CSL Fault Count LED to indicate which type of fault or lockout has occurred.

The ACD function puts a time-out period of 3 minutes on the compressor before re-starting on a normal cycle.

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

6. Under Voltage (source voltage less than 195 volts)

12/03/2012 40 GI301

Sensor Temperature Calibration – all four 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 the special PC software and PC USB port cable to set the appropriate offset.. The PC screen has
direct readout of the four monitored temperatures, it allows a visual determination of temperature settings, and
can be used to offset the temperature sensors for troubleshooting and demonstration purposes.

NOTE

Temperature Sensors

Temperature sensors installed in TTHERM GEO heat pumps are NOT thermisters. They are digital devices

calibrated at the manufacturer. They are polarity sensitive. Be sure to connect the red and white wires in their
correct shared terminals. The black wire is the data stream wire and will have its own screw terminal.

Bad sensor, safety – if the internal logic detects open sensor wire, a shorted sensor wires, or a incorrectly wired

sensor; the green POWER LED reverts to a pulsing mode. See Operational Indicators.

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

operation. Software declared bad sensor default

ST = 70° F LWT (heating) = 32°F LWT (cooling) = 77° F

Troubleshooting – GEO Logic Control

Check the GEO Logic Controller, Operational Indicators, section of this manual for in depth description of the
diagnostic information available by observing the LED’s.

Internal fuses – the source loop, hydronic loop pumps, and desuperheater pump are fused on the high voltage

pump relay board.

Troubleshooting/Repair Helps

Open Loop Operation – TTHERM GEO heat pumps are factory set for open loop operation. Open/Closed loop

operation is set with Jumper J 11 on the left side of the GEO Logic controller. The jumper must be in place on

J11 if the unit is operated on an open loop. The GEO Logic controller protects the heat exchanger from freezing
by causing the compressor to shut down when the leaving water temperature reaches 38° F open loop and 20° F
closed loop. The compressor will remain off for 2 ACD’s, and the EARTH LOOP FLOW/ SOURCE WATER
LIMIT & HP STAGE 1 LED’s will pulse, while the water runs and warms up. The compressor will then restart
again providing heat until the LWT again reaches 38° F open loop and 20° F closed loop. If this

CDT = 200° F (DDT = 190° F (CDT on dual compressor models = 200°F)).

 The pump hookup decal provides the fuse size and details.
 The GEO Logic controller is protected by the circuit breaker on the low voltage transformer.

1. This GEO Logic 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 GEO Logic controller is “acting strange”, one immediate step would be a power down
reset. Simply turn off the 240 volt source power. When the green POWER LED goes out, count to 10,
and re-energize power supply.

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

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 jumper 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.

3. The THT, dual compressor units, have two separate refrigerant circuits. Each compressor has its own

refrigerant circuit. The high pressure switches and low pressure switches in both circuits are wired in
series. If the heat pump locks out low pressure or high pressure, each of the refrigerant circuits will need
the pressures monitored to determine which circuit caused the lockout.

4. Use general heating/heat pump system logic information and basic understanding of the terminal block

wiring functions when measuring voltage to determine proper operation.

12/03/2012 41 GI301

routine continues the heat pump will not be able to maintain the temperature in the house and the backup heat
will come on. Possible causes would include:
Open Loop Closed Loop

1. Supply water filter that needs cleaning 1. Inadequate source water flow

2. Inadequate source water flow 2. Antifreeze protection inadequate

3. Water discharge line that is plugging up 3. Heat exchanger needs to be cleaned

4. Entering water temperature less than 50 degrees

5.Heat exchanger needs to be cleaned

WARNING

IF THE TTHERM GEO HEAT PUMP IS IN A HARG LOCKOUT WITH THE EARTH LOOP FLOW/
SOURCE WATER LED ON SOLID, DO NOT RESET THE POWER TO THIS HEAT PUMP UNTIL
EARTH LOOP FLOW HAS BEEN ESTABLISHED. IF THE COMPRESSOR IS OPERATED IN
HEATING MODE WITHOUT WATER FLOW, THE EARTH LOOP HEAT EXCHANGER COULD

FREEZE RUPTURE. FREEZE REPTURE IS NOT COVERED UNDER WARRANTY.

Troubleshooting the pump relay board

The pump relay board has 4 LED’s which display which relay is closed.
Yellow – is on when open loop water solenoid is energized.
Green – is on when the source and load pumps are energized.
Red – is on when the desuperheater pump relay has SWH terminal energized..
Blue – is on when the 2

nd

source loop pump is energized.

The relay board has 2 – 10 amp fuses providing power for source loop, hydronic, and the desuperheater pumps.
These fuses are 10 Amp type GSF.

Checking the high voltage input terminals

The high voltage enters the pump relay board on the upper left side, terminals W1 & W2.
This high voltage comes from the source side of the contactor – L1 is connected to W1 and L2 is
connected to W2.

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.

Checking the high voltage output terminals
The high voltage leaves the pump relay board in 2 locations.

1. Terminal Block (TB1) is located in the upper right side of the pump relay board.

See the decal located to the right of the TB1 to determine wiring.
High voltage should be present at the respective terminals when the corresponding LED is on
Load pump terminals will be hot at the same time as source pump terminals.

Tip – if source voltage is present on the board, one of the LEDs is on, and high voltage is not present at
the corresponding terminals, the switching relay is bad and the board will need to be replaced.

2. One of the desuperheater terminals (SWH) is located between the fuses and the other SHW terminal

is below the fuses. These terminals carry High Voltage. To determine if the desuperheater pump

has power measure across these two terminals. If a desuperheater pump needs to be disabled be sure
the high voltage to the TTHERM GEO heat pump is disabled. Remove the SHW wire from between
the fuses and place it on the parking tab (P) above the relays.

The pump relay board has one low voltage output for the 24 volt AC water solenoid. The 24VAC “common”
wire is gray and is connected to terminal T7 on the right side of the pump relay board. The 24VAC “hot” wire is
brown/yellow and is connected to terminal T4.

Tip – if the yellow LED #4 is on and the low voltage is not present at the water solenoid
terminals, the switching relay is bad and the board will need to be replaced.

12/03/2012 42 GI301

Troubleshooting – General

WARNING – Refrigerant Evacuation

WHEN REFRIGERANT IS EVACUATED FROM A UNIT WITHOUT ANTIFREEZE IN THE WATER TO

REFRIGERANT HEAT EXCHANGERS, WATER IN THE UNPROTECTED HEAT EXCHANGER

MUST BE REMOVED OR CONTINUOUSLY FLOWING TO AVOID A POTENTIAL HEAT
EXCHANGER FAILURE CAUSED BY FREEZE RUPTURE. FLOWING WATER THROUGH THE

HEAT EXCHANGERS EVEN IF ANTIFREEZE PROTECTED WILL SPEED THE EVACUATION
PROCESS.

Troubleshooting Guide for Water-to-Water Geothermal “Heating”

Undercharged system

Overcharged system

Low load flow

High load flow

Low source flow

High source flow

Low return load

temperature

High return load

temperature

Scaled source coil

Restricted filter/drier

Bad TXV / No Bulb

charge

Undercharged system

Overcharged system

Low load flow

High load flow

Low source flow

High source flow

Low return load

temperature

High return load

temperature

Scaled source coil

Restricted filter/drier

Bad TXV / No Bulb

charge

Head

pressure

Low Low Low High Low Low Low

High High High Low High High High

High Low High High High High Low

Low Low High High High Low High

Low High Low Low Low Low High

High Low High High High High Low

Low High Low Low Low High High

High Low High High High Low Low

Low High Low Low Low Low Low

Low High Low High Low Low Low

Low High Low High Low Low Low

Subcool Suction

pressure

Superheat Compressor

Amp draw

Load temp
differential

Troubleshooting Guide for Water-to-Water Geothermal “cooling”

Head

pressure

Low Low Low High Low Low Low

High High High Low High Low Low

Low High Low Low Low High Low

Low Low High High High Low High

High Low High High High Low High

Low High Low Low Low High Low

Low High Low Low Low Low Low

High Low High High High Low High

High Low High High High Low Low

Low High Low High Low Low Low

Low High Low High Low Low Low

Subcool Suction

pressure

Superheat Compressor

Amp draw

Load temp
differential

Source temp

differential

Source temp

differential

12/03/2012 43 GI301

Preventive 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.
Should cleaning become necessary, do so using the following standard cleaning procedure:

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.

Air Coil Condensate Drip Pan and Drain –Inspection and cleaning of the condensate drain system during the

cooling season will help prevent the system from plugging up, potentially causing water damage to your
structure and floor coverings. Inspect the “P-trap” to make certain it remains clear of obstructions. In some
areas, airborne bacteria can cause algae to grow in the drip pan. In these areas, it may be necessary to treat the
drain pan with an algae inhibiting chemical, as this algae together with lint and dust could plug the drain piping.

Air Coil – In order to keep your TTHERM GEO Heat pump operating at peak efficiency, the air coil should be

inspected and cleaned when necessary. If the coil is excessively dirty, the coil can be cleaned with a household
vacuum cleaner and a soft brush. The aluminum fins are fragile and bend easily, so take great care not to

damage the fins, and remember, these fins are sharp, so take the needed safety precautions.

12/03/2012 44 GI301

Troubleshooting – General

Troubleshooting Guide for Water-to-Air Geo “Heating”

Undercharged system 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 Low

Low return air

temperature

High return air

temperature

Scaled source coil Low High Low Low Low Low Low

Restricted filter/drier Low High Low High Low Low Low

Bad TXV / No Bulb

charge

Undercharged system Low Low Low High Low Low Low

Overcharged system High High High Low High Low Low

Low air flow Low High Low Low Low High Low

High air flow Low Low High High High Low High

Low source flow High Low High High High Low High

High source flow Low High Low Low Low High Low

Low return air

temperature

High return air

temperature/Humidity

Scaled source coil High Low High High High Low Low

Restricted filter/drier Low High Low High Low Low Low

Bad TXV / No Bulb

charge

Head

pressure

Low High Low Low Low High High

High Low High High High Low Low

Low High Low High Low Low Low

Subcool Suction

pressure

Superheat Compressor

Amp Draw

Air temp

differential

Source temp

differential

Troubleshooting Guide for Water-to-Air Geo “cooling”

Head

pressure

Low High Low Low Low Low Low

High Low High High High Low High

Low High Low High Low Low Low

Subcool Suction

pressure

Superheat Compressor

Amp Draw

Air temp

differential

Source temp

differential

12/03/2012 45 GI301

TXV-C

GEO

LOOP FIELD

7/8

1/2

7/8

1/2

TXV-H

1/2

LWT

EWT

AIR COIL - COND

COMP

F/D

PT-1 LL

PT-2

HL

SDW­COIL

DW-RT

DW-ST

RV

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

- - - LINE SET - - -

BV

BV

FL

BL

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

GR301 P1

Rev. A 04-17-2012

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

T-2A

LOOP

COIL

EVAP

P

P

TM

TM

TXV-C

7/8

1/2

7/8

1/2

GEO

LOOP FIELD

TXV-H

1/2

LWT

EWT

F/D

BV

FL

T-3

T-3A

LOOP

COIL

COND

P

P

AIR COIL - EVAP

COMP

PT-1 LL

PT-2

HL

SDW­COIL

DW-RT

DW-ST

RV

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

- - - LINE SET - - -

BV

BL

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

GR301 P2

Rev. A 04-17-2012

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-2A

TM

TM

TTHERM GEO™ Residential

Limited Product Warranty

Effective February 1, 2012

TTHERM GEO warrants to the 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 TTHERM GEO are free
from manufacturing defects in materials and workmanship, when used under normal conditions and when
such product has not been modified or changed in any manner after leaving the manufacturing plant. If
any product or product parts manufactured by TTHERM GEO are found to have manufacturing defects in
materials or workmanship, such will be repaired or replaced by TTHERM GEO. TTHERM GEO shall
have the opportunity to directly, or through its authorized representative, examine and inspect the alleged
defective product or product parts. TTHERM GEO may request that the materials be returned to
TTHERM GEO 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 TTHERM GEO or its
authorized representative.

TEN YEAR (10) LIMITED WARRANTY ON REFRIGERATION COMPONENTS

TTHERM GEO 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, TTHERM GEO will repair or replace them at
their discretion.

LIFETIME LIMITED WARRANTY ON UNIT CABINET

TTHERM GEO warrants that the cabinet to be free from defects in materials and workmanship for the life
of the unit. If any panel fails TTHERM GEO will repair or replace them at their discretion.

TTHERM GEO 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, at the original installation site on all parts
excluding the compressor, reversing valve, expansion valve, and heat exchanger(s). TTHERM GEO shall
cover labor costs according to the Repair / Replacement Labor Allowance Schedule for a pe riod of ten
(10) years from the date of original purchase, 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 GX002

TTHERM GEO

TTHERMGEO.COM
[e-mail]
P: 507-463-0506
F: 507-463-3215

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 TTHERM GEO Commercial Limited Product Warranty.

2. TTHERM GEO 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 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 pro duct 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 TTHERM GEO 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 condens ation drains properly from the unit.

9. Replacement of a product or product part u nd er this limited warranty d oes 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, TTHERM GEO shall have the opportunity to directly, or through its
authorized representative, examine and inspect the alleged d efective pro duct 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 TTHERM GEO 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 TTHERM GEO or its designated location, 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, includin g, 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
TTHERM GEO or its authorized representative.

6. Workmanship 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 OWNER 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. TTHERM GEO 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 GX002