Split Systems

Enviroteq manufactures compressor units to interface with air handlers made by air-to-air heat pump manufacturers. To date we have successfully utilized air handlers manufactured by Tempstar, Heil, Janitrol, Coleman, Luxaire, Nordyne, and others. Because all metering is accomplished in the GEO compressor unit, it is necessary to remove all restrictors or other metering devices from the air handler(s) before installation.


Up to three stages of heating and cooling are available with our most advanced units. Utilizing two disparately sized compressors (a two-ton and a three-ton, or a three-ton and a four-ton compressor, for instance) we can provide capacities of from two to five nominal tons, and from three to seven nominal tons, from a single unit. This allows sizing of units for heating in northern climates without oversizing for cooling.

When loads are light, the unit's smaller compressor operates extremely efficiently with coils sized for ten tons and provides the highest levels of humidity control during the cooling mode. As the load increases the system stages up to the larger compressor and the small one drops out. So, a home with a five ton heating load and a three ton cooling load, for instance, can operate nearly all winter with little resistance supplemental heat and most of the summer utilizing only stages one and two, but with stage three (five nominal tons) available for those rare sweltering days when three tons might not be enough.

Zone TwoZones

Up to three air handlers are utilized with our dual compressor GEO unit to achieve zoning (three zones). These air handlers are normally "twinned" or "tripled" so that all evaporation and condensing is accomplished in both DX coils simultaneously. The panels between the air handlers are removed so that either or both air handlers can operate. If only one zone calls for conditioning the blower for that zone operates delivering conditioned air only to that zone. A proprietary component and method for preventing backflow, developed by Sunteq, keeps return air from short-circuiting the DX coils. The air handlers can also be remoted ie. one can be installed in the basement and the other in the attic, utilizing zone valve assemblies provided by Enviroteq. But, the twinned air handler technology provides higher levels of operating efficiencies because of the substantive size of the total DX capacity when only a single compressor is functioning. Staging and zoning achieved by independent thermostats provides a level of control unmatched by other manufacturers.

Compressor Protection

No manufacturer goes to greater lengths to protect it's compressors. Enviroteq utilizes a number of expensive components and features - components not essential to satisfactory system operation - just to go to that extra effort to protect the compressors. Many of these components and features are included in the one way metering circuit described below.

One way metering circuit

Enviroteq's one way high pressure liquid circuit provides the ideal way for metering refrigerant in both the heating and cooling modes. When warm liquid refrigerant returning from either DX Coil (acting as a condenser) enters the one way circuit it (1) passes through a heat exchanger in the suction line accumulator to flash off any unevaporated liquid in the accumulator, then (2) it goes to a receiver which regulates the volume of refrigerant in circulation, storing excess refrigerant when necessary, and (3) as it leaves the receiver it passes through a large filter/drier which constantly cleans and dries the liquid, and finally it is metered to the evaporator coil by a balanced port thermostatic expansion valve capable of adjusting refrigerant flow rates from two through seven nominal tons.

Suction line accumulator with integral heat exchanger (assures that no liquid refrigerant can enter the compressor(s)
Liquid receiver stores excess liquid refrigerant to balance the charge.
Large capacity liquid line filter/drier keeps refrigerant clean and dry.

Oil equalization tubes (dual compressor models) assures adequate lubrication for both compressors

Unlike with bi-directional (two way) expansion valve metering, the one way circuit allows these additional functions to be added to a geothermal heat pump.

Additional compressor protection:

Oil equalization tubes (dual compressor models) assures oil return to both compressors and thus adequate lubrication for each compressor.

Additionally, there is a high pressure lockout switch (manual reset) installed on the hot gas discharge line and a low pressure switch (auto reset) on the suction line. Compressor short-cycle protection is provided by a time-delay on the control circuit which delay's on break so that the unit is usually ready to run on start-up.

Superior heat Extraction with Oversized heat exchangers:

Large capacity water-to-refrigerant heat exchangers provide for exceptionally efficient heat transfer and high evaporator and condenser efficiencies, as well as extremely low pressure drop for exceptionally high flow rates. When it comes to efficiency and performance the name of the game in geothermal heat pumps is heat extraction and heat dissipation capacity. While most manufacturers size their water-to-refrigerant heat exchangers to match the capacity of the compressor(s), the heat exchangers on Enviroteq's closed loop models are greatly oversized - 200% on average - for incredibly high heat extraction efficiency.

The chart below shows the number of and sizes of heat exchangers installed in the variious Enviroteq closed loop models and the per cent of oversizing.

A Model B Nominal Capacity
(In Tons)
C Heat Exchanger Rated Size
(In Tons)
D Oversized
C divided by B
GEO 24CL 2 5 250
GEO 35CL 3 5 167
GEO 48CL 4 Two-5 250
GEO 59CL 5 Two-5 200
GEO 70CL 6 Two-5 167
GEO 84CL 7 Two-5 143

Exceptionally high water flow rates

Most of our competitor's larger sized geothermal heat pumps require two (expensive) circulator pumps in order to provide sufficient water flow for satisfactory operation. All of Enviroteq's larger closed loop models (4 nominal tons and up) have two heat exchangers installed so that there are four parallel water flow paths available for the water to follow (two in each heat exchanger). This results in very low pressure drop so that, when coupled with a Sunteq designed closed loop, flow rates on the order of 14 to 15 gallons per minute can be achieved with a single circulator.

While this may add to the cost of an Enviroteq geothermal heat pump, the savings resulting from the need to purchase only a single circulator pump are significant - on the order of $300.

Circulator Ready

In addition, all Enviroteq geothermal closed loop models come with a 1¼" copper male threaded adapter ready for circulator flanges as well as wiring in liquid tight conduit ready for connection to the circulator's terminal box. This reduces field wiring requirements and saves significant installation time. During the heating mode, the circulator runs on any call for heating. During the cooling mode the circulator is controlled.


An oversized desuperheating heat exchanger on the hot gas discharge line is provided as an option on all Enviroteq models. Desuperheating hot vapor provides virtually free domestic hot water during the cooling mode and low cost DHW during the heating mode. A thermostat provided by Enviroteq is mounted on the discharge line and brings on the DHW circulator (not provided) only when there is sufficient hot gas energy to be exchanged.

There's more!


Compu-Sun Energy Audit provides a comprehensive computerized heating and cooling load analysis for the consumer which estimates annual geothermal heating and cooling costs and compares them to the costs of any other type of system: Natural and L.P. Gas, Oil, Wood, Coal, Electric and Air-To-Air Heat Pumps.

Compu-Trac Energy Use Tracking Program — a computerized tracking program that tells you how well your system is (or isn't) doing compared to projections.

Innovative Geothermal Heat Pump Installation Techniques that are unique in the industry, such as:

  • Loops that operate only under pressure of gravity
  • An air-purging, debris-filtering, self-replenishing water storing reservoir that shows the homeowner - at a glance - when water needs to be added to the system.

The more you know about refrigeration, the better we look!