I live in a 2400 sf century house that has been renovated including roof, siding, windows and is fairly well insulated and sealed. We had the geothermal system installed in 2012, the unit is a Bosch ta049. We have a closed ground loop horizontal. We found that the auxiliary was coming on a lot during the coldest days (Dec.-Feb.) with hydro bills in the $800 range for each of those months where usually we average $300. I had the system inspected and they told me that it was fine although the temp of fluid coming in was 31F and 36F going back out. ( the tech acknowledged that was i bit small of a difference) The temp at the plenum was 79F. I had the tech disconnect the aux. ( he disconnected it at the low voltage lead). ( My sister and another friend have very similar systems with the aux disconnected and their homes are warm ) With my thermostat set to 65F I went to bed. I got up at 6am and the house temp had dropped to 60F. It will get up to about 65F during the day but not any more than that. I have had the worst experience with customer service imaginable and am looking for second opinion from anyone who knows this system. Unfortunately, I don't trust the people who sold/installed it.
In the heating mode, Entering Water Temp (EWT) is higher than Leaving Water Temp (LWT) because you are extracting heat from the water. Generally speaking, a 5* Temp diff is about normal. Air temp rise should be about 20*~25*. You need the service tech to perform a Heat of Extraction (HE) for the unit. That number should be within 10% of factory specs.If they don't know what that is... FIRE them and hire a company that knows Geothermal. Bergy
Thanks Bergy, I didn't expect a reply so fast, much appreciated. I will be calling another geothermal place on Monday to get the second opinion and will definitely tell them I want the "Heat of Extraction" tested. What is your thoughts on having the aux. disabled? Am I putting my system at risk in any way? Thanks again. 12acres
No harm is done. However, Most Geo systems are designed to include some Aux Heat. How much is a question for your contractor. Bergy
We are just north of Cobourg (one hour east of Toronto) My contractor charges $99 for the inspection so I expect to pay the same for a second opinion. I will not use the company who sold it to me as I have had too many issues with them.
