thowell
July 27, 2011, 8:01pm
1
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.
rthoroman
July 27, 2011, 9:38pm
2
Make sure you stay within the SoP or state licensing SoP. Disclose or report on what you can’t see.
A geothermal heat pump or ground source heat pump (GSHP) is a central heating and/or cooling system that transfers heat to or from the ground.
It uses the earth all the time, without any intermittency, as a heat source (in the winter) or a heat sink (in the summer). This design takes advantage of the moderate temperatures in the ground to boost efficiency and reduce the operational costs of heating and cooling systems, and may be combined with solar heating to form a geosolar system with even gr...
mboyett
July 27, 2011, 10:02pm
3
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.
jacaron
July 28, 2011, 2:08pm
4
Check for:
http://www.geothermal-heat-pump-resource.org/
roconnor
July 28, 2011, 3:09pm
5
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 …
dandersen
July 28, 2011, 9:24pm
6
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?
1 Like
dedwards
July 28, 2011, 9:55pm
7
Ditto! Operate the system using normal operating controls, report what you see, move along.
1 Like
rfessler1
July 12, 2019, 8:52pm
8
just ran into one of these today. 1st time i have seen one. There were 3 units in the crawlspace. but the homeowner only mentioned 2, and there were only 2 thermostats inside. im wondering if the 3rd may have been to heat the pool.
