Geothermal

[Tim C. Howell]

Have an inspection coming up where the home is heated / cooled with goethermal. Any tips or suggestions on what to be looking for? Or where to find some information on inspecting these systems.
Thanks everyone,

[RAY THOROMAN]

Make sure you stay within the SoP or state licensing SoP. Disclose or report on what you can't see.



http://en.wikipedia.org/wiki/Geothermal_heat_pump

[Michael R. Boyett]

Assuming you have a ground or water source heat pump then this might be pertinent. It is from a post about a home I did last Sept:

The 2 year old home I inspected last Friday had 2 ground source heat pumps. I had an independent 3rd party service provider (Stan’s A/C) inspect them for me and American GeoThermal, the original system installer, was there as well to describe the systems and answer questions.

Each unit was a ‘packaged system”, i.e. the water pumps, exchanger, compressor, evaporator coil were all in one enclosure in the attic.

• These particular systems essentially trade the condensing unit fin system (that would be an air-source heat pump) for polypropylene looped tubing buried 300’.
• One 600’ loop (300’ down, 300’ back up) handles ~one ton of A/C and there was a total of 7 tons at this house therefore 7 down holes.
• I think the tubing was 1.5” but I’m not positive of that, it’s all buried and nothing is visible above ground (strange to see a home like this with no condensing units outside).
• The tubing holds water w/ anti-freeze and is pressurized to around 12 psi (Stan’s tech said they pressurize to 65psi but I don’t know the pros/cons of such).
• The package unit in the attic has a compressor with a small amount of refrigerant, maybe 12-16 oz they said. Therefore neither Stan's nor the original installer recommended putting gauges on the refrigerant so as to not risk losing any.
• Both companies said the use of temp splits was acceptable and the systems would compare to deltas of a regular a/c system but maybe a degree or two higher. One of them quoted 15-24 degree splits could be expected.
• The tech did check circulating water temp and pressure and splits on both systems….$150 ea system.
  
• Even after being assured by the Builder/Seller/Occupant and the original installer that the systems were running perfectly the Stan’s tech did find very low water pressure on one system and low delta-T on the other so the client’s money was well spent. It didn’t appear anything significant was wrong, the systems just needed ‘tuned up’.
• The Seller said his August electric bill on this 4,100 sf two-story home was $150 (I didn’t see the bill however). Avg daytime temp ~97° probably.
  

I learned a little about geothermal but it was so hectic at this inspection that I wasn’t able to learn nearly as much as I wanted to.

[John M. Acaron]

Check for:
Source of water (quality)
Pressure
Filter
Type of system (open loop, closed loop,...
Check Temp at each water furnace (Thermostat/register)

http://www.geothermal-heat-pump-resource.org/

[Robert J. OConnor]

You can easily get overwhelmed inspecting some of these systems. Keep it simple on a home inspection.

It's very similar to inspecting a standard air source heat pump (packaged or split), except water is pumped through the ground to heat/cool the refrigerant instead of using outdoor air drawn thru a unit with a fan to heat/cool the refrigerant.

And make sure to note the limitations of your inspections and parts of the system (e.g. ground loop) thats not visible for inspection.

JMO & 2-Nickels ...

[David A. Andersen]

Don't do any of this BS!

Do your job like any other inspection. Observe and report!

90% of the HVAC guys can't do geothermal, so why do you want to join the ranks of the unknowing and get your business in a bind for something you are not required to assess?

[Doug Edwards]

Ditto! Operate the system using normal operating controls, report what you see, move along.