TETCO ES4-WS Series Single Stage Water-to-Water unit image 5 year warranty

ES4-WS Series Single Stage Water-to-Water

Imagine walking through your home with warm feet on the coldest days. It's not a dream; it's the TETCO ES4-WS series geothermal system. Let the power of radiant heat warm your feet, and your home. Water-to-water systems circulate warm water through tubes installed under the floor, heating the room from the ground up.


  • Optional cupronickel heat exchanger
  • Desuperheater with internal pump
  • High and low access ports
  • Thermostatic expansion valve
  • Electronic controls with safety lockout
  • Front, top & rear access
  • Copeland scroll compressor


Model Capacity Cooling Heating
Btu/hr EER Btu/hr COP
TWS036 Full Load 34,700 18.2 26,600 3.1
Part Load - - - -
TWS048 Full Load 52,800 17.7 42,100 3.1
Part Load - - - -
TWS060 Full Load 60,000 17.1 53,000 3.1
Part Load - - - -
TWS072 Full Load 73,300 17.7 63,100 3.4
Part Load - - - -
TWS084 Full Load 83,600 16.1 74,200 3.1
Part Load - - - -
TWD120 Full Load 104,600 14.5 100,100 2.8
Part Load 63,500 19.8 57,500 3.4
Unit Notes
  • For the source water loop, open loop models use 1" fittings.
  • Rated in accordance with ISO Standard 13256-2 which includes Pump Penalties.
  • Heating capacities based on 32°F EST & 104°F ELT.
  • Cooling capacities based on 77°F EST & 53.6°F ELT.
  • Entering load temperature over 120°F heating and under 45°F Cooling is not permissible.
  • Floor heating is most generally designed for 85°F entering load temperature.


"A" coil (hydronic)

The specially matched "A" coil allows the split geothermal system to be added to an existing air handler or furnace in retrofit applications. Additionally, the "A" coil can allow the system to operate in a dual-fuel application where backup heat is supplied by a traditional furnace.

Air handler (hydronic)

These multi-positional air handlers are specially matched to our split systems for maximum performance. The match also qualifies the system for the 30% U.S. federal tax credit. The air handler can be installed in remote parts of the home, or hard to reach areas where space is at a premium.

Programmable thermostat

Keeps the home more comfortable by operating the unit on a set schedule and temperature range. This also saves on energy costs by setting the unit back while the home is unoccupied.

Non-programmable thermostat

Designed to take maximum advantage of the multi-stage functionality of the unit. This allows the unit to achieve maximum savings by only operating at the right range to match the current weather.

Flow centers - pressurized

Circulates the fluid through the unit and the geothermal loop field. These types form a completely closed system.

Unit air pad (plastic or foam)

The unit air pad creates a buffer between the unit and the home. This buffer prevents any vibration from the unit to be transmitted into the home which improves the already quiet operation of the unit.

Extended warranty

Adds that extra peace of mind by extending the standard warranty to a full 10 years on parts and labor.

Consumer purchase plans

With a wide variety of payment options and terms, our consumer payment plans make installing a geothermal system easier and more cost effective. By deferring your initial payments out, you can start enjoying your new system earlier and take time to obtain many of the various rebates and tax credits offered.

Disposable pleated filter

This type of filter uses a pleated media to remove dust and other particles from the air stream. It is important to check these filters regularly and replace them as needed.

Electrostatic filter (washable)

This type of filter is a permanent media filter that can be washed from time to time as needed. This eliminates the need to buy new filters.

Electronic 24 volt air cleaner

This type of filter uses an electrically charged media to increase filtration performance. This improves indoor air quality by removing more particles from the airstream. This filter requires the occasional media replacement.

EWC zone control

These highly sophisticated controls work with dampers in the ductwork to create multiple zones throughout the house. You can utilize one unit, but have different temperatures in each zone. The control panel controls both the unit, and the zone dampers.

Flow center - non-pressurized

Circulates the fluid through the unit and the geothermal loop field. This type of system uses an expansion tank that can be topped off should the loop require it due to thermal expansion.

Auxiliary external electric heater

Adds that little bit of extra heat on those few coldest days. Also helps to balance the system size by balancing out those few extreme days. These heaters are installed in the supply air duct outside of the unit. Mostly used on horizontal style equipment.