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WaterFurnace ES036 ES Split Series Dual-Capacity Heat Pump


Cons: Freon Loop Seal Failed, Ground Loop Water Pump Failed, Compressor Failed.

I have had a WaterFurnace ES036 Heat Pump installed since August of 2004.  I have had a few problems with the system in the past. 

One problem existed as a result of  maintenance.  Apparently when a Tech was checking the freon loop pressure a pin hole was created by the probe in the rubber gasket.  As a result, over three months, the system lost freon thus causing the system to operate inefficiently.  The unit was just over 1 year old.

Another issue the Water Pump was found bad and replaced.   Most notable though, the unit's Compressor went bad.  This is a recent development which left me with two options.  Either replace the Compressor or replace the Heat Pump with a new Heat Pump.  Both options would cost me money.  Apparently there has been quite a few problems with the Bristol Compressors installed in WaterFurnace units.

Option 1 replacing the Compressor would leave me with a unit which has a new compressor (not Bristol), and with no warranty on the new compressor.  Cost to me to have this compressor replaced under warranty in about $660.00 US.

Option 2 would replace the Heat Pump with a new Heat Pump and a 10 year warranty.  Cost to me to have the Heat Pump replaced with an Envision 3 Ton unit is $2,200.00 US.  Supposedly there is a discount on the cost of the Heat Pump from WaterFurnace.

Overall the concept of Geothermal HVAC is good and there are a lot of benefits.  I don't feel this particular Heat Pump has lived up to the cost of the unit.  Geothermal HVAC systems are to be relatively maintenance free.  I have had quite a few problems and have installed an extensive monitoring system so I can keep an eye on it.  The monitoring system and trend charts can be found at


Pros: Environmentaly friendly

Cons: Failed Unit

I am extremely disappointed in Waterfurnace! I have had this unit for 4 years and have had nothing but problems. Approximately, 6 months after the unit was installed repair service was required. On average, the unit is repaired twice a year. Despite my calls to Waterfurnace, who claim to have a great customer service department, I am left with an inadequate product. As I read in a previous review, I too, am given the option of replacing the compressor at a cost of 800.00 or replacing the unit for 3400.00 I find this unacceptable! What-ever happened to standing by your products? I will not buy another Waterfurnance product again.

WaterFurnace ES036 ES Split Series Dual-Capacity Heat Pump

ES Series splits are designed primarily for outdoor installations, and are connected to an indoor air handler (or fossil fuel furnace) via refrigerant lines and control wiring. ES units utilize the ozone-safe R-410A refrigerant to meet the most stringent EPA requirements. It is installed as a ground loop system. This model is dual-capacity. When operating at partial capacity, efficiencies are higher. The specifications below are for when the unit is operating at full capacity.

Energy Star QualificationYes
Energy Efficiency Rating (EER)17.1
Cooling Capacity38,500 BTUH
Heating Capacity26,000 BTUH
Coefficient of Performance (COP)3.6
Additional Features
Heating Seasonal Performance Factor (HSPF)
Release Date
Seasonal Energy Efficiency Ratio (SEER)
Model Name/TypeMPNEAN/UPC

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Related Media/Links:

Add related videos, links to item guides, etc.

Link to Geothermal HVAC installation.  The whole process is documented including installation pictures.  On the Real Time Diagram page is a monitoring system to watch all aspects of the Geothermal HVAC system.  The Diagram is updated every minute and is typically two minutes behind current time.  Site lists project scope, key learnings, trend data (Natural Gas usage before and after installation, Electric usage before and after installation).  There are also charts of Earth/Ground temperatures from 1 foot depth to 11 foot depths.  There is also a Blog which documents system issues.



Troubleshooting/Known Issues:

Had an issue other users should know about? Put it here.

Typically in the first year after installation, the ground loop solution pressure will drop and need to have fluid added.  This applies to all types of Geothermal HVAC installations.  You should keep an eye on the electric usage of the Heat Pump.  Another way to tell that the loop pressure is low is that the system will run a lot longer in the 2nd stage heat, or in the cooling mode.  A service call should be made to check the loop pressure and limit the inefficient use of electric power.



How To:

Advice on installation, customization, and anything else.



Related Items and Accessories:

Not necessarily items within the community, just any other recommendations.

Monitoring System to document the efficiency of the Geothermal HVAC installation.  When the system does not operate properly the Auxiliary Heat mode is used.  Depending on the style of Auxiliary Heat it could increase the cost of operation considerably.  When the system ground loop pressure changes (Typically within the first year of installation) the Heat Pump operates inefficiently increasing the costs significantly.  Check out existing monitoring systems as and





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