The second coil is for a water to water unit.

The air coil is the condensor when heating and the evaporator when cooling.

It probably would have helped if I'd written "aircoil" as well.

AHHH. And so another piece of the puzzle is inserted...

I still don't get it about the two coils as drawn in the diagram. Can I imaine that the connections on these two coils are in reality on one physical coil? Plus the addition of the DSH line?

The large coax coil on the left is if the unit is a water to water unit.  It would take the place of the air coil.   In your case,  you have the air coil and not the water coil.

You are correct that the DSH water line is not shown

I appreciate all of your help. My AC guy likely has had a few drinks... Will catch him on Monday. So far, this education has brought me an overview level of understanding of the system as a whole with the exception of the TXV. It reads like it is a metering device for more precision in the flow of refrigerant.

Engineer - There are four vertical bores. I believe three are 230+- feet deep and the fourth is 190+- feet deep. It is more loop than required because I wanted to be certain the loop was efficient. The unit is over sized for a couple reasons.. We did not know a smaller unit was available and the house was designed to accommodate additions on all four sides. (It';s good to keep notes for future reference).

GeoDean - Thanks for the explanation. The diagram would have been as clear as your text had I paid attention to the note by the water coil...

Is the coax as simple as three separate lengths of copper pipe rolled up together in a coil, secured together and insulated? I imagined this elaborate contraption developed in a dark lab with guys in white coats. It's simplicity is almost a let down.

Like low charge, poor water flow theory.
j

Joe, I think the suggestions made about low refrigerant are spot on. The quick reference guideline for for refrigeration circuit is very helpful. They all seem to point to low refrigerant or possibly restricted TXV. The hvac guy will be here Monday to do his magic and we will learn more. For now, the WF is running... "OK". It is working harder then normal to keep the house warm, but not as bad as the other night when the dsh plumbing was allowing flow and gave us 164 degree water.

Thank you to everyone who shared advice and ideas. I enjoy learning form the experts! I'll update on Monday unless something new happens tomorrow.

John

I'd consider switching to aux until this is resolved. Very high discharge temps and low refrigerant flows aren't good for the compressor. Worst case scenario is that the oil overheats, breaks down, forms acids, and eats the compressor windings.

Others here may think I'm crying wolf, and may be able to quantify the risk or confirm that the compressor has protections against this.

Engineer - I'm with you. Just learned some more info. Studying how this stuff works I now get it. It is crystal clear to me now and it all makes sense. Two things cleared up in my head. The DSH is NOT part of the coax coil. It is actually a separate heat exchanger located behind the coax coil. I can trace the discharge line to it, and then from it to the reversing valve. This clears up why there was VERY hot DHW with no corresponding rise in air temp. The DSH was stealing all the btu's from the refrigerant before they even made it to the air coil. OK on to the TXV. It makes perfect sense how it regulates the flow of refrigerant. I traced out the two capillary lines to see if something was obvious and of course out of curiosity. The line that goes to the bulb was coiled up and resting on the discharge line, which is pretty hot! So I separated them by about two inches.

Took new measurements:
-Loop pressure: In is 52 psi and out is 42 psi. Now has a 10 psi drop! I've never seen this much pressure in the this loop or my last. Why would this happen?

-Loop Temp: EWT - 66.2 degrees --- LWT = 65.8
delta t = .4 degrees. This is .1 degree better then original measurement. Still poor.

-EAT (entry to return air grill) = 75.9 degrees --- LAT (between blower and dampers) = 83.5 degrees
delta t = 7.6 degrees. This is 4.7 degrees better then original measurements

Question: There are thermistors attached to the discharge line and the suction line. They are wired to the CPU on the controller board. Are these devices "Threshold - 0/1 - on/off" devices or "linear 50, 51, 52, 53..." measurement devices?

Multiple Conclusions:
1. The capillary line resting on the discharge line seems to have changed the symptoms.
2. The original super hot water temps were due to thermosiphoning as predicted by Engineer.
2. I need the WelServer service with several hundred sensors.
3. The appeal of the Greeter job at Walmart is directly proportional to my perceived increases in knowledge and understanding...

John

here is a pic of a coax heat exchanger.

Thanks. Now I know whats inside the bundle of insulation. Was curious about the tubing used. Looks like twisted pair wire but the strands are hollow. Do you hav a pic of the DeSuperheater?

The DSH would be similar only smaller.

OK. Now I've found a problem..
The current at the compressor:
- Stage 1 = 5.6 a
- Stage 2 = 5.6 a

I verified stage two by placing S2#6 on and 7 off. The LED display shows stage one and two active (LED's 2 and 4 flash).

The diagnostics says there should be 12vdc to 20vdc on the contacts in the molded plug for the compressor solenoid. I can't find a compressor solenoid. Is it behind the compressor lurking where I'll burn the hell out of my forearms again?

Other data measured:
NOTE: Temperature probe I have is not easy to get a stable reading but this is close!
-Temp on the discharge line is 194 degrees
-Temp on the suction line:
Air Coil / reversing valve side of filter/drier is 24.2
Coax side of the filter/drier is 24.5

I've not found documentation describing the temps on the discharge and suction lines.

One thing I did notice: When calling for stage two, and the compressor current did not reflect the additional draw, the filter/drier begun to frost/freeze over. I think this is the problem...

Thoughts?
(please be kind if this is way off base - my brain is fried)

John

This should help with respect to what you should have for temps coming out of the compressor's discharge.

I have the exact same model as you - a WF Envision 038.  (Look here for exact model number: http://welserver.com/WEL0043/ , top diagram).

The blue line in the chart below is actual data for my 3 ton (038) unit - 1st stage only (I never run in 2nd stage).

Your 194° measurement, for compressor discharge, assuming it's accurately measured, seems awfully high.  And so high, I agree with Curt (engineer) to immediately turn off the unit until you can get service.

You need to turn off your DSH while troubleshooting, and, to have an 'apples-to-apples' comparison to my chart (my DSH is always turned off).

The chart is 55 weeks of data.  The 3 ton data (blue line) is not accurate earlier than -45 weeks.  I had a leak in my compressor such that compressor discharge temperature was rising.  (At about week -45, you can see significant temp drop after evap coil was replaced.)

Compressor discharge temp will vary slightly as a function of EWT.

More WF Envision 3 ton (038) performance related information is also available at the above link.

Hope this helps.

Best regards,

Bill

Alright. Found the cause of the problem. The Comfort Alert module is bad. This device monitors various signals and sets alarm codes with flashing lights on board, sends a code to the controller board and to compatible thermostats. It has another function: To rectify 24VAC to 24VDC for the stage 2 solenoid in the compressor. I traced the stage two signal through the system and into the Comfort Alarm module. When 24VAC is applied to that connection, it is supposed to provide 24VDC on the connector to the solenoid. Stage 1 operation seems fine. When stage one active, there is no DC voltage on the solenoid connector. When stage two is called for, the Comfort Alert module produces a whopping 1 VDC.

This explains the overheating of refrigerant in heating mode AND the freezing evaporator coil in colling mode over the summer. I think....

So. Tomorrow I'll find and order the CA module and see what happens. Hopefully the compressor was not damaged.

Will post results when the CA is replaced.

Thanks to everyone for your help!

John

WHOA.

That may be a problem, but I doubt it is THE problem. Inability to go into high stage would not cause all the other symptoms we've discussed - iced suction / TXV, very very high discharge temps.System should run perfectly fine in low stage even during a high stage call. A high stage call ignored by the compressor but acted upon by the blower would result in higher airflow and lower airside delta-T.

I may be wrong, but I think you'll find you still have a charge or TXV issue even after swapping out the ComfortAlert.

You might very well be right. The HVAC guy is coming tomorrow to check the refrigerant. That is not something I will even touch, just yet...

Hear me out and see if I at least got the theory right:
In heating mode. Thermostat calls for stage two. The blower speeds up and the airflow increases past the air coil. The compressor does not speed up and increase the heated refrigerant into the air coil The increased volume of air passes through the coil, but there is not an increase of BTUs' in the refrigerant. I "think" the refrigerant would transfer it's BTU's early in the air coil thereby condensing sooner. Would that not cause higher pressures hampering the flow backward from the compressor? If this is right so far, it makes sense that the refrigerant would exit the air coil much colder then the design calls for. That would explain the icing on the filter/drier and into the COAX. The TXV would be wide open allowing greater capacity for refrigerant flow, but there is no additional capacity available. So the refrigerant remains colder then normal as it enters the coax. The water temp in the coax is somewhat of a constant. so Lower then designed refrigerant temp into the coax = lower then designed refrigerant temp out. Onward to the compressor. If I got this right, the back pressure on the discharge line into the air coil would cause higher temps and pressures to make the TXV open up. But the backup is in the air coil because the refrigerant has turned to liquid early in the coil.

In cooling mode, the revers happens. There are more heat (BTU's) in the air coming past the evaporator coil then there is refrigerant to absorb it. So the evaporator coil freezes up. I fought that problem most of the summer thinking the problem was the fan speeds, cycle rates, compressor lockout and other cool features in the thermostat and WF controller.

Or maybe not. hahaha

This has had 100% of my focus for days now. Hopefully the image in my mind of how this works is not too far off. Hopefully.... But if not, please please set me straight before I unknowingly destroy a WF NDV038.

Thanks!
John

Increasing blower speed while all other parameters remain the same would reduce pressure in the aircoil (condenser) as the more-quickly condensed gas refrigerant makes more room for gas. More room and same gas flow means lower gas pressure. The TXV operates based on conditions leaving the evaporator, which in heating mode is the watercoil.

That's if things are working normally.