Hello ~ below is my first geo inspection form.  Other than the missing methanol %, does anything strike any of you?  Any comments?  The delta T's seem OK from what I've learned on this forum, but I'm not sure about the heat of extraction stuff. 

Thanks!

Ona, your Heat of Extraction (HE) is a good indication of your unit's ability to remove heat from the earth, and is stated as a capacity number in KBTU per hour.

In your case, the HVAC professional measured it at 23.3 KBTU/hr.

If you look up the specs for your 3 ton ND038 Envision unit, operating in 1st stage, with the blower fan running at 1050 CFM, EWT at 41°F, and flow at 8 GPM, the unit's HE should be about 17.9 KBTU/hr.

Your technician's number is high, but, on the good side.  My guess is there's some error in his/her pressure measurements and/or looking up the pressure-to-DeltaT value.

The conclusion to draw is your Envision unit is probably running as per WaterFurnace spec at the moment, at about 17.9 KTBU/hr.

With all of the discussion at the moment, on other threads, about running with EWT near 32°, here are some interesting points about your Envision unit: at 30° EWT with the same 8 GPM flow, your HE will drop to 14.5 KBTU/hr.  And your unit is listed to run as low as 20° EWT, where HE is still a reasonable 11.6 KBTU/hr.

And if you run your unit in 2nd stage, you can get 16.4 KBTU/hr HE with 20° EWT.  This HE is just a little less than the 17.9 KTBU/hr you're currently getting with 41° EWT.

Point is your Envision unit's got a lot more capacity available if needed, assuming you have a solid design for your water loop pipe structure.

Lastly, you and I have the exact same 3 ton 2 speed Envision unit.  Below is my HE for my 3 ton unit (blue line) for the past 24 days.

Best regards,

Bill

I would like to see the actual measured RLA (Running Load Amps) rather than the nameplate RLA. That 16.6 came right off the nameplate - lazy. I would expect compressor amps for your system under those conditions to be near 10.

The GPM doesn't jive with the measured pressure drop for an Envision 038: a 5 psi pressure drop corresponds to > 10 GPM, unless the antifreeze substantially increases the delta-P over pure water.

The GPM waterside and its delta-T correspond well with listed heat extraction and expected heat extraction per WF tables

Blower amps of 4 seem high to me if you have the ECM blower, which your model number suggests you do. The evap split is on the high end of good, suggesting 350 CFM per nominal ton. That's fine, but needing ~1000 Watts to move that amount of air suggests a high static condition.

I'd like to see ESP across the blower and actual compressor amps. both are easy to measure with moderately priced instruments.

I'd like to see voltage at the heat strips when they are drawing the 34 amps. Are your strips 8.0 kw nominal? If not, that amp reading is suspect as well.

The HE figure corresponds with 2nd stage operation. You get that heat from the ground plus what the unit uses in electrical power for a total of a bit more than 30 kbtuh

Just my $0.02 at a 100% internet discount...

I noticed this too, but, forgot to comment on it.  My question is, isn't the ECM motor a DC motor?  And if so, wouldn't it require a DC Ammeter to get this value?

Best regards,

Bill

In theory yes, but from the point of view of cost to run, best place to get current is upstream of the conversion to DC. Mine runs from about 0.3 amps up to 1.2 or so. My ampmeter isn't the best, reads about 10% high, and I don't know what power factor the ECM conversion electronics run at, but assuming unity PF gives worst case power use.

Thank You! This is good info even though I'm a bit disappointed in my installer (or his tech). I'm going to collect my thoughts with the info you've provided and perhaps address this with the installer. I may have more questions... either way, it'll probably be after the new year when I finally get it together. So, if you have any other thoughts, please feel free to share.

I suspect all of the amp draw numbers came from nameplate since they match.
The good part is HE is right where it should be for high speed operation with good delta T.
It is probably good he didn't try to check the charge as the HE would prove that unnecessary.
That cabinet probably has EAL 10 aux heat rated 34.7 amps @ 208V.
If you are going to write down amp numbers at least use an amp meter, takes 5 min at most.

Does anyone have a better form than this, or is this one as good as it gets?

Funny, I was thinking of asking for the same thing. I'd like something fairly comprehensive for initial commissioning and then yearly checks. Airside + waterside temps and flows, ESP, amps all the way around. Ideally there would be entries for both stages of operation in heating and cooling, but with the understanding that some modes may be impractical to test depending on weather at time of test. It might make sense to test heating and cooling modes on favorable days in alternate years.

I'd be just as glad this particular tech left most or all tools in the truck - less potential for damage

WaterFurnace has what I think is a good form.

See page F-2 in "Troubleshooting Guide - E Series" document.

It starts with Step 1 noting details for Flow Rate.

Step 2 is details for Temperature Rise/Drop across source side heat exchanger.

Step 3 is details for Temperature Rise/Drop across air coil.

Step 4 is details for HE / HR calculations.

Step 5 is details for Super Heat / Subcooling.  Caution is noted that Step 5 should not be performed unless a problem exists.

An improvement to the form would be to add appropriate voltage and current measurements.

A further improvement could include measuring Power Factor, which would then enable computation of EER or COP, depending on mode.

And going even farther, for cooling mode, an improvement could include measuring Wet and Dry Bulb humidities, enabling Latent vs. Sensible cooling capacities.

I believe the 5 (or 4 if no problem exists) steps in the WF form plus my other suggestions would result in a very comprehensive 'health check.'  Unfortunately, I doubt the form would be cost effective for a business in a competitive environment, as the time required to take all the measurements and do the calculations would be significant.  Most customers would prefer to not have to do an annual maintenance.  Paying top dollar to get all of the above info I don't think is a high priority with most customers.

Hope this helps.

Best regards,

Bill

Since we are speaking quite unfavorably about my installer, I took his name and info off the original post form (he had given me permission to post). I left my installer out there and exposed - not many people would do this.

While I understand and appreciate all of your feedback, I do also want to speak with the installer and see what his opinion is on this. Perhaps the tech is supposed to measure these things with his own instruments and didn't? I've already called about the methanol % omission.

Perhaps the cost is at issue here? If my installer wants to give his customers a good price so that they will have annual service maybe this is the way? It does look like they followed steps 1-4 in the form above doesn't it? Or am I missing something about details for all four steps?

So, my next question is: Are these all readings that I can take? Which instruments and how much do they cost? Can I get to the circuits to measure as a homeowner or does a pro need to do this? Since it does not appear I should feel confident in my installers maintenance, I would like to learn what I can to verify readings and performance.

I don't understand why you should lose any confidence in or respect for your installer and/or technician. There is no indication in any of the report  that suggests that the system is working at less than factory specification.

Yes maybe he should have whipped out his clampon meter to get running amps and voltages for documentation purposes. However from his HE figures there is no indication that the system is running at other than peak performance.

This would also indicate that there was no change in antifreeze protection from initial install (unless someone drained it and refilled with plain water and purged it. I think highly unlikely).

I try to setup my maintenance checkups biannually. I can then verify performance based on the the season (HE when heating and HR when cooling) we are entering. I typically only do both at unit commissioning and when there is a problem.

In my 'day' job I work on factory automation - central control rooms for power plants, refineries, paper mills, chemical plants, etc. I have a saying with regard to process data and that is that "I would rather be ignorant than deceived" In other words, I want the system to display no data rather than bad data.

That applies here - don't write nameplate amps on a checkout form if there is a chance of it being misinterpreted as "today's data" Same with heat strips. I'm not sure I'd take the trouble to measure strip amps on each visit, but I'd confirm their proper operation prior to heating season via noticeably warmer LAT.

I continue to believe 4 amps is high for the blower, and merits investigation. Per my WF docs full load on the blower is 7.2, so the clamp amp meter may have come out of the truck for that one. Furthermore, the system could develop rated heat transfer but at much higher than normal compressor amps owing to a refrigerant restriction. Same applies in cooling season - a scaled heat exchanger will transfer nearly rated heat but at much higher refrigerant pressures and compressor amps. Yearly amp checks compared with data from commissioning would catch this.

I do not advocate measuring refrigerant pressures if unit is delivering expected heating / cooling at expected amps

My point in all this is that geo is a premium choice, chosen with the expectation of long term savings to pay off the high first cost. Therefore maintenance checks need to confirm not just expected heat transfer but that system continues to provide that heat transfer at or near expected efficiency.

Hooking up a gauge set to measure refrigerant pressures is the LAST thing one does while servicing these units!! Every time a gauge set is hooked up,and removed, a little refrigerant is removed from the system. Over time this can be enough refrigerant to affect the units performance.

Bergy

Thank you... I appreciate all of your feedback. While I have not lost all confidence in my installer, I do have reason to have a discussion with him. I still feel good about his intent and ethics, so it's not as bad as I may have made it sound. On the other hand, I appreciate having a place like this forum to see what can be done better or changed. I won't accuse my installer of anything, rather discuss some of the issues that you pro's have brought up. I appreciate this feedback as well as the feedback I've received in the past.

I do feel as if my system is running well right now, but I want to feel like I'm in good hands as my system get's older and things are bound to get worn down.

Yes

Every manufacturer I've worked with suggests that initial diagnostis start with look /feel /listen.
Technichian clearly brought in a thermometer and pressure gauge as well as whatever level of experience.
So while it was clearly a cursory exam it is far from negligent. Most of the concerns mentioned can be detected by sight, sound, touch, or water temp pressure methods.
Curiously start up sheets from manufacturer's also ask for superheat and sub cool while mfgs simultaneously ask that we not put gauges on equipment unless necessary.
All and all I'd say that if this was a "free" annual check up, it was worth more than that, albeit not particularly thorough.
If it was the initial start-up checks I'd be more concerned.
I like the idea of amp and capacitor checks, but do not give away hours of time (IOWs no free checkups).
Joe

This inspection was completed one year after installation and I paid $120 for it. I know that $120 is not a lot of money, but I am still going to discuss this with my contractor.

Fair enough, I was under the impression that it was pro bono.
Not saying that excuses poor workmanship.
Occasionally contractors have technicians who work for them who do not represent them well. I always implore my customers to offer feedback if they are dissatisfied. Otherwise I'd never know.
Your installer should appreciate the chance to correct a bad PR move.
Joe

While I don't have a geo system yet, I wish that any of the techs that have come to my home to do annual maintenance on my A/C systems would give me even half as much information as was provided on the inspection form. All I have ever received was an invoice which was significantly more than the $120 paid on Ona. I hope to find a company that can provide me with something other than a bill when we relocate.

I am still learning about geo systems so that I can ask halfway intelligent questions when I have to choose a contractor. So am I correct to assume that at start-up, I should get a data sheet similar to above or at a minimum request on from the contractor? How would I evaluate the results from a start-up test if I did receive the form? Is this something that I should consider requesting a third party to evaluate before I accept the system? If so, how would I go about locating such a third party evaluation?

If I were looking design and operation specifications for the system I plan on installing, should I expect to get such specifications from an HVAC engineer? I would also think that there should be design and performance specifications for the loops as well? Don't mean to hijack this discussion, but I was impressed by the data form right or wrong.