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Old 01-08-17, 08:16 AM   #11
pedro
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I think you can get by on a lot less flow but you need a good and accurate way to measure bare minimum entering water temperature and leaving water temperature. If your entering temperature is 58F then I would should for 1.5 GPM per ton. You should be looking for 5.25 GPM in stage one and 7.5 GPM in stage 2.

Work on getting both stages functioning first as Steve describes. Then you can work on plumbing to optimize the system. On stage 1 you will be shooting for 28k - 32k BTU/h being removed from the water. Absorbed heat = (Entering water temp - Exiting water temp) * 60 * 8.35 * GPM.

I have run as low as 1 GPM but output of the unit dropped down to a little less than 3 ton at that time. With an entering water temp of 56F the exiting temp was around 38 which I wouldn't really go below 40F. On the low end of my pressure tank setting now my flow is around 1.35 GPM and I still have a delta of 11F on the water entering at 56F. Your brother's entering water is a few degrees warmer than me and we live on the same latitude.

Is he enjoying the cold snap? I moved to this house 4 years ago with the Geo being installed in 2008 I think. When I first came here at a setting of 68F on the thermostat it would run 24 hours a day and use some backup heat in weather like this. It was never really comfortable at that temperature. As Steve say most installers just install and go. If it puts some heat out they are done. Yea it worked and on cold days it used backup but I have proved it isn't needed if the whole system is optimized.

Since I have sealed air leaks and optimized the geo and now it hasn't used backup heat in a couple years. Even with the negative temps the night before I still only ran around 16 hours yesterday. The house is 2400 Sq ft and I do just fine with a 3.5 ton.

Can you describe your plumbing more? How many hp is the well pump? Over 3/4hp you need to watch your cycles. 3/4hp and less I wouldn't worry about it unless it is on and off every minute or something stupid like that. Do you know the piping from the pump to the house? The size of piping to the geo unit? You said you have a 30 gallon pressure tank what are the dimensions on it or model number?

I'll gladly give you feedback on what I have done over the years. I need to work on attic insulation next as it can be increased to help some more. Once I get there I will look at getting a 2 stage unit and possibly downsize to a 3 ton as I think I can get there.

You can see my runtime just over this week. A two stage would help me with nice long run times on those small use days.


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Old 01-14-17, 02:52 PM   #12
Fathompin
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Pedro, thanks for the info. This is like my own system and I will examine it closely.
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Old 01-14-17, 02:53 PM   #13
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This answered my questions, Thank you very much.

I just wanted to say, things were not as bad as I made it seem, mostly because I can’t write worth beans. Based on the comments given, I set up the Y1 & Y2 from the thermostat so that it operates two loads/stage for the heat pump, no problem. Thus, I am not concerned with well pump usage, and will just let the thermostat control what loads it wants to run. My comments about the well pump running constantly were confusing (best to just drop the reasons why I made it confusing and save getting even more confusing…you described that usually the thermostat should control the turn on of the water valve when it calls for heat, that answered my question). The water pump is controlled, as it should be, using the well pressure tank controller (60-40 psi), the heat pump controls two water valves, one for each load; I did find that the two valves are not very good at controlling flow, I thought setting those would be a cinch, but I found it almost impossible to set the flow for one valve at 7 gpm and then when two valves are open the flow tops out at 12 gpm. I believe the problem is that the well is NOT able to provide 12 gpm and that will take more investigation on my part, because that seems out of line.
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Old 01-16-17, 07:29 PM   #14
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What pressure is going through the geo? You might look at getting a pressure reducer from Menards to help control the flow a little better.
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Old 01-16-17, 07:45 PM   #15
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Also I need two more post so I can answer PMs. I will just put the information here I hope you see it Ron. He had a question on how I monitor flow to my geo.

I use a raspberry Pi, a flow meter with a 1 gallon pulse output and some Python code to monitor it.

The python code uses an interrupt each time it records a pulse from the meter. The interrupt triggers code that calculates the time since the last pulse and from that I can calculate gpm since I know the time it took for 1 gallon to flow through the meter.

I have a 1/2" flow meter now. If I knew then what I know now I would have bought a 3/4". Since then I found a cheaper version:

Master Meter Flexible Axis Water Meter available at Flows.com!

I own the 1/2" model here:

DLJ Water Meter

I will probably buy a 3/4" next and move the 1/2" to a smaller project.

If you got any questions or need help let me know.
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Old 01-16-17, 07:54 PM   #16
pedro
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The raspberry has a simple dweet.io to send the data somewhere where I can look at when I need to but it isn't recorded.

https://pypi.python.org/pypi/dweepy/
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Old 02-17-17, 10:03 AM   #17
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I have a single stage HP with a 2 speed fan. I replaced the well pump several years ago and it was suggested I get a variable speed pump that runs slow when only the HP needs water but speeds up for other household uses. I can turn on all my water with the heat on, including a commercial greenhouse, and the pressure remains constant. I have an 8 liter (2.1 gal) pressure tank for my 2.5 ton unit. I believe the well pump is 3-phase. It cost more but I have had now problems for 5 years. I get plenty of heat for my 2400 sq ft house in N Indiana and rarely have my auxilary heat go on.
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Old 02-18-17, 09:10 AM   #18
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Plantman,

Let us know what brand of variable speed pump you have. Your five years of no problems is impressive.

I have been thinking of doing so ay my own home, but many friends/clients have had problems with the variable frequency drive (VFD) unit that modulates the speed of the deep well pump. In particular, lightening seems to fry them.

For an open loop system, a VFD well pump seems ideal and I am pleased to see it working for you. I had them put in a few of my installs, but am now unsure.


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Old 03-04-17, 09:32 AM   #19
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I found an installation manual for a Grundfos SQ/SQE, so I think that is what I have. It comes with a 2 year warantee.

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