Water to Water Geothermal heat pump replacement with lp boiler

a clamp on probe will get you the temps. the pressure is less important, the temps in different places will tell you a lot about the flow. I'd pull one of the circulators with the isolation valves and see if there is a flow check in the circulator. If there is and it is undamaged and you are getting ghost flow you have problems with the way the circulator for the zones and the circulator for the heat pump are connected together.

Please report back if he figures it out. Inquiring minds want to know!

Were you able to calculate gallons per minute at 8 dt? you can see how much heat you were extracting.

How close are the drilled grouted wells to each other?????????????????????????????????????????????????????

When you said three 180 foot deep wells piped in series that struck me as very odd. These drilled wells were apparently drilled and had a looped drop pipe system installed with the "so called "geothermally enhanced" clay grout that acts as an insulator rather than an open loop system.

You may have one problem which could simply be the 3 wells are too close together and cannot shed the heat or reclaim enough cold from the surrounding ground-go figure-due too shallow a depth.

The driller that did this did you no favors as a 600 foot deep open loop cased well with a six inch pipe cap on the first pipe joint with a marine concrete plug in the last 10 feet of the casing would have given you almost 590 feet of water column for heat exchange with a single drop pipe set in the first 200 feet of water column.

UGH, I hope the problem is in the heating/cooling systems basic adjustments or a circulator that is allowing ghost flow.

was there glycol that had not been maintained in it?

maybe others will have a different perspective, but i don't see how an appliance that has probably a 20+ year payback period and seems to be retaining its water and refrigerant is "too old".

If your goal is to provide good service to your customers at a reasonable price, I could see why it's not a good business decision to get involved with a 20-year-old piece of equipment that may never have been properly installed to begin with.

i'm not convinced that there is any problem with the appliance, the way the load loops are piped looks very questionable, that it doesn't have a good way to get the right flow through the appliance.

Given everything else refrigeration now, it is likely to outlast a new one by decades.

It looks like the piping is very much separable from the appliance itself, that a new appliance could be installed pretty easily if it fails after the piping is corrected. If it is piped correctly you should be able to just as easily add a mod con to the loop as the heat pump by connecting both with closely spaced tees.

Maybe @hot_rod will chime in but this it what I think.

Recommended pressure drop is 6.2 psi. At 6.2 psi pd the flow should be 16.5 gpm per the mfg.

you say that you have a 2.0psi PD and that the mfg says 2.9pd is minimum and that at 2.9 you flow would be 11 gpm.

At 2.0pd you flow is only 9.53 gpm (thats what I came up with) Cv of the unit is 6.74.

so at 9.53 gpm your flow is only 86% of the mfg MINIMUM

and 57% of the recommended MFG flow.

No surprise to me why the unit short cycles and has no capacity.

You need someone who can size the correct circulator for you to get the proper flow. Too many installers guess. That doesn't work for me.

Sometimes they get away with that approach but more often they fail. Heat pumps need the right flow

Or the load side might need to be modified so that it is primary secondary, it looks like it is plumed so the zone and heat pump circulators are interacting with each other now.

So we start here:

the three bores are 180+180+180= 540 feet deep

Each bore has two drop pipes 180 feet long=360 of drop pipe per bore times three equals 1,080 feet of pipe plus the pipe from the home to the first well then 17 feet to the second well and 17 feet to the third well and the return pipe to the water furnace from the last well.

540 times 2 the number of drop pipes plus 100+- feet from the last well to the water furnace plus the length of the first pipe 100+- feet from the water furnace to the first well, SO you could say you have a total run of pipe of 1,200 feet+- of one inch pipe SO…………………

on many days i also feel like i am the only person in my office that understands math…

Using the optimistic pipe material choices in the Geo-Flo ground loop calculator with what I understand as your loop parameters works for your existing ground loop pump at around 12gpm. I would confirm all construction details and play with that calculator if you don't have the ground loop documents. The documents would have the design parameters to justify the equipment choices. The calculator has entries for the heat pump heat exchanger pressure drop which needs to be factored in. You can confirm that in the heat pump installation docs at a certain assumed gpm to use in the calculator.

If you have to install a second pump it looks like it can be added to your existing pump station. The existing pump is out of production but you can find one with similar head/gpm if you need to, or maybe find one on eBay. The downside of more gpm and a second pump is more watts. Two pumps is going to be 500W+. Lower gpm = less power overall.

If the ground loop was all clogged up and the pipes can be confirmed in the model best case, maybe you will have solved/improved your situation.

It sounds like you have two major issues. Clogged field and lack of buffer tank. Sounds like the field is now fixed so all you need is to add a small buffer. Even the bigger pump if needed, won't change the operation much and not really the cause of most of your issues.

Neither one of those means replacing the a heat pump that is still working. Adding a simple in-line two port buffer can be done by any boiler tech.

As for replacement when it does actually die, I think your best bet is to find a better geo tech that can install a new unit.

Propane replacement doesn't make sense as it costs almost the same as resistance heat. About the only non-geo replacement is to replace the air handlers with ducted cold climate heat pumps and keep the resistance backup boiler for any floor heat. You can run the heat pumps for bulk heat and the floor heat only enough to take the edge off any cold slab.