New Oklahoma Installation

Installation of my first Geo system begins today in Southern Oklahoma. It is a 5 ton Climatemaster with Desuperheater. My electric bills have been averaging $250 a month so I'm interested in comparing the difference in my future bills. My old system is a 10 SEER, 5 ton air to air heat pump.

 

Wells drilled

There have been some delays with the drillers but the wells were just completed and they are digging the trench to the house. They went with 5 vertical loops (250-300'). With any luck, they will get the loops all connected and run into the house before the end of the day.

 

Great. Let us know how you make out.

 

Wow - I don't normally read of 250-300 feet of vertical well per ton up north. We do use that much here in Florida owing to the need to reject lots of heat into warmer-than-typical ground.

Was that design decision based on local soil conditions or an abundance of caution?

It should produce very favorable entering water temps and good efficiency...keep us advised

 

Summer Temps

We have had the system installed for about 8 months now and overall, we are pleased. I may be mistaken on the well depth above. Sadly, I was not able to be home during the actual drilling phase so that is probably more an error on my part. I'm not really seeing significant savings on my electric bills but it has been an extremely hot summer. Which brings me to my question.

Shouldn't the system be able to keep up with the 100+ temp days we have been having here? I keep the thermostat set at 76 so I wouldn't think this would be a problem. However, during the heat of the day, the system is running on 2nd stage cooling and still only able to get it down to 78 or 79. To me, this seems to be a problem. If I wanted the temp to be 70 in here, I think we would be having some serious comfort issues.

At night, with the temp drops outside, the system is able to keep up without difficulty and is usually only running in 1st stage cooling.

Thoughts?

 

Loops

250-300' of loop may be 125-150' borehole

 

Solar heating

If the system can't keep up, it may be as simple as solar gains from the sun shining. Blinds and such should still be closed.

 

We are keeping the blinds closed and most of the rooms have blackout/insulated curtains as well. We didn't build the house so not sure of the R-level of insulation in the walls. We could definitely use some additional insultation in the attic. However, I still expect the system to be able to meet the temp designated at the thermostat. If an air to air system can do it, I would think a geoexchange system would have an easier time due to the efficiency of the process itself. Am I wrong?

 

While air source can struggle with high entering air temps, water source can struggle with high entering water temps or a load greater than capacity.
Your entering water temp would be a good first test.
Design info would also be interesting.
Have you lived in the home long enough to gauge how 5 ton airsource performed in similar conditions?
Last summer was pretty hot.
j

 

This is an interesting post. I live just south of you in Texas, and last summer was a real test for my 16 year old Addison 3.5 ton. After one of those 107 degree days the unit would not cool the house below 78 degrees, so it ran constantly on the 76 degree setting. So, I have been looking into replacing it. The first installer who came to bid said I needed more insulation in the attic. He was right, so I added 8 more inches. On the next 107 degree day, the unit did the same thing as before. So far, every Water Furnace dealer who has come to bid has said they can't overcome the temperature difference when it gets that hot. I'm guessing they mean my house is too old.
Butch

 

temps

You may what to check the temperature of your ground loop before you go to the expense of replacing your unit. It could be that the loop is supplying fluid that is "too" hot to get the the temps you want.

 

Yes, Ryan. That is a good point. One WF dealer, who came out to make a bid on one of our 107 degree days, felt of the line coming out of the ground. He said the ground coils seemed to be working properly. In other words, the water temp from the ground seemed to be the right temp. So, my question is, will coils that are working properly for a 3.5 ton unit still work properly for a 4 ton unit? Hopefully, the 4 ton unit will be working on the low speed of its compressor most of the time.
Butch

 

Thouching the coil isn't enough. He should measure the fluid temp and the compare it to the preformance charts in the owners manual. This will tell you the how well the unit is working. Unless you know how much loop is my the ground there is no good way to answer the rest of your question.

 

If he did not put a temperature probe into the P/T port, he has NO idea what the loop temps were.

Bergy

 

He wasn't here to troubleshoot a problem. I had never seen him before, so I'm not sure I would have wanted him to perform an invasive procedure on my operating system.
Butch

 

This is the second time that I have heard of an installer feeling the lines and saying the loop is OK. This really baffles me.

 

Yes. It is kinda unscientific, but he didn't come out to diagnose a problem. His business is selling the product.
Butch

 

Thanks for all the posts. I'd like to ask again: Do you think the 4 ton unit will do any better job on a 107 degree day with the coils that work just fine on a 3.5 ton unit on a 100 degree day? (I'm saying the 3.5 ton unit works just fine on a 100 degree day because of the fact that it satisfies the 76 degree thermostat setting and cycles off and on without running more than it did when it was new.)
Butch

 

I see, Ryan. Thanks. We're working blind with this Addison 3.5 ton. I can't find anything on the internet, and if I ever had any manuals, I've misplaced them.
Butch

 

In order to get your home down to 76 on a 107 degree day it would have to be designed for a 31 degree temperature difference. This would cause you isssues on days when the temperature was not that hot outside. You will cool your home quickly but you will hardly remove any humidity. An AC/HP has to satisfy two seperate loads, Sensible (the temp); and Latent (the humidity). It is a delicate balancing act most homeowners do not understand. Study ACCA Manual J and it will give you some insight. After you have chosen the equipment to be installed you then need to perform a loop design takiing many factors into account. Horizontal loops had to be a nightmare this summer out in Texas with tthe lack of rain.