I said I was not convinced that the equipment was correctly sized

I think that everyone agrees you have enough capacity. As they agree, staging is an issue, but you need to be clear on what you want (geo always uses much more electricity than NG).

..and we are using much more electricity than we did before, which I think is worse for the environment than the natural gas we heated with before.

I'm not sure that the number of parts breaking will change much unless you go with a much simpler system. But maybe some of it was just bad luck or "infant mortality" issues.

It really is shocking to me that geo is not saving us money.

Accurately measuring efficiency from 3+ systems and accounting for differences in weather (including wind), setback and household electricity use takes some specialized equipment.

Jon, I'm not sure I'm following your comments as they relate to the quotes you pulled into your post.

My concern with sizing is whether a 3 ton water-to-water GSHP is an appropriate first stage for our house. If the gas boiler backup has to kick in at relatively mild temps for us to be comfortable, that's an issue and we probably should either abandon geo as a first stage and just go with gas, or upsise the W2W tonnage, right? Hence the title of this thread from way back when.

While there wasn't total concensus here, I've developed a concern about whether a control fix is going to be enough. Then there are the 3 pumps required to operate the system, which I don't think anyone here suggested was a best practice. Add to that a concern that I'm not being provided with a Manual J or any evidence that load calculations have been completed. And that a company that told me 3 years ago that they had hundreds of successful geo installations is now telling me they don't want to make any changes until they're 100% sure that they're the right changes to make...and the project continues to drag on with them doing nothing to make things better before the heating season.

That's where I am.

"The SpacePak, on the other hand, was installed incorrectly, and needs to be moved, duct size needs to be increased, and return air has to be increased."
This makes me suspicious. SpacePaks are kind of a canned duct system. How does anyone goof up sizing?

". Then there are the 3 pumps required to operate the system".
Frankly I don't remember the context of this, but multiple pumps are not uncommon. Best practice and most efficient design are not the same thing. We also have to concern ourselves with best bang for the customer's buck and customers' budgets. Part of that equation is cost/kw which is why best ROI in an area with 12 cent/kwh may not be the same as an area with 8 cent/kwh electricity.
The pros here spend a lot of time to learn from others. I won't say that makes us unique, but most of us here have discarded some or many of the geo "truths" espoused by major trade organizations or manufacturers. Some contractors do not spend evenings and Sundays recreationally chatting about work. They learn more slowly.

Posted By joe.ami on 10 Apr 2013 08:30 AM
"Is everyone saying that my installer will need to take loop temps with both 2 pumps and 3 pumps running in order to give us the info on whether the third pump is needed?"

No I think your installer should take third pump offline. No measurment required.

Doc has some good thoughts on what might save the system (though I assume purchase of the WF 7ton is off the table right now .

Hi Joe...you recommended taking the third pump out on page 3...others also commented that having pumps in series is inefficient, and I think most here believed they were installed as an afterthought because the loopfield doesn't support the equipment. But, I may have interpreted some of this wrong--I thought I was beginning to understand it.

Ahhh April, my page 6 (I was trying to avoid reread).
"Best practice" is often a term used by attorneys and remote designers.
An extra pump is easily defended by installer as redundancy (something Doc supports on larger jobs).
So both are true: I told you I'd un-hook it and "not best practice" may not be applicable to those 3 pumps.

tamar let me expound upon my Spacepak suspicions.
Because of it's nature a high velocity system has fairly specific installation/application instructions from the manufacturer. To screw it up is to ignore the book. I'm not sure whether new guy doesn't know about reduced duct size on HV or if installer ignored installation instructions.
Someone is very wrong.

Posted By joe.ami on 25 Aug 2013 12:12 PM
Ahhh April, my page 6 (I was trying to avoid reread).
"Best practice" is often a term used by attorneys and remote designers.
An extra pump is easily defended by installer as redundancy (something Doc supports on larger jobs).
So both are true: I told you I'd un-hook it and "not best practice" may not be applicable to those 3 pumps.

Tamar was referring to the 3 circulation pumps installed in series to overcome the 1" line pressure drop which sees the entire system flow need for 8 tons. Inaddition, all 3 pumps come on when only one heatpump is running, at least that is my understanding.
Now, this line is going to be exchanged for a 1.5", which should help significantly. Then you can put 1 circulation pump in line with each heatpump (one for the split and one for the w-w) and save a lot of operational costs.
There is nothing wrong with the concept of having the 3 ton w-w carry the baselad of the house, and then have a boiler supplement everything. And have the split unit run everything which is not radiant.
The manual J is close to irrelevant at this time. The issue is the correct controls and identifying energy hogs, like 3 pump in series to overcome bad design (1" line to loopfield).
I come back to a single heatpump (7 ton high temp comes to mind) which might be cheaper and better in the long run. Tamar, keep us posted here, I have the feeling that your endeavor is far from over.

I like 2 smaller pumps in parallel in larger applications with multiple heatpumps, where each circulation pumps carries less than 50% of the load. The main reason is redundancy, if one pump fails, the other one revs up automatically.

Posted By joe.ami on 25 Aug 2013 12:30 PM
tamar let me expound upon my Spacepak suspicions.
Because of it's nature a high velocity system has fairly specific installation/application instructions from the manufacturer. To screw it up is to ignore the book. I'm not sure whether new guy doesn't know about reduced duct size on HV or if installer ignored installation instructions.
Someone is very wrong.

New guy is already out of the picture. His recommendations are dated August 8, but our installer refused to provide the pdf to us until a word was changed....which took several weeks, because this guy is a PM for a very large company.  As I mentioned before, I think someone called in a favor and that much of this was for show. The installer had already said they expected to have to move the SpacePak and do something about return air before new guy even did a walkthrough.

My interpretation is that they wanted their plan on the letterhead of a third party so that, if needed, they can claim they performed due diligence before attempting to rectify our system issues (this time...previous times it's obvious that they didn't do their homework). And to stall.

The installing company doesn't carry WF, and so it appears they are determined to make the existing geo equipment work. Their current plans, as far as I can tell, are to replace the Phoenix with a buffer tank and gas boiler. I will also be asking them to replace the SpacePak, as I think it has been abused by the faulty installation and that's why parts have failed.

Are there certain boiler or buffer tank characteristics that I need to ask about or request?

If they didn't do a manual J, what should they have done or should they do? How will they determine what the details of the "program" should be (what temp is buffer tank maintained at? How long after heat is not satisfied should boiler engage? etc).

Doc, thanks for the invitation to keep posting. I'm sure you are right that there's lots more drama to come.

Improper installation of spacepak does not cause damage to the system, it simply kills performance.
How long should system run before boiler engages is a variable that is impacted by outside temperature and wind speed. The point is if you start with geo everytime and augment with boiler, then the operation cost would necessarily be lower than the boiler running all the time.

Both TXV and blower motor have needed replacing on the SpacePak. I don't know what TXV does, but I assume there was stress on the blower motor because of the system design (not enough air in, not a straight shot out, in simple terms). I have already told the installer that if they don't replace the SpacePak, they need to significantly increase the warranty. Of course just my saying it doesn't make it so, that's why I'd much prefer that they replace it.

In terms of what you want your installer to spend money on this is less important. It's possible those repairs weren't necessary, but done in an ill advised remedy to airflow problems.

I had not thought of that....good point. I know the blower motor was toast, as it sounded like a freight train and was hiccupping and chugging. Replacing it was like night and day. This was during heating season. The TXV supposedly failed during the hottest days of summer last year, and it took 3 weeks to get a replacement because it is soldered to a coil (or so I was told). It was my first month working from home and it was miserable. There may now be a better option than the SpacePak that has a variable speed motor. It may not even require as much return air, which would mean they won't have to punch a hole in one of our bedroom ceilings. I will need to figure out how to evaluate that option...I know this isn't the place for that since it's not geo.

They only thing that requires less return air is something with less capacity.

Posted By tamar on 26 Aug 2013 10:52 AM
I had not thought of that....good point. I know the blower motor was toast, as it sounded like a freight train and was hiccupping and chugging. Replacing it was like night and day. This was during heating season. The TXV supposedly failed during the hottest days of summer last year, and it took 3 weeks to get a replacement because it is soldered to a coil (or so I was told). It was my first month working from home and it was miserable. There may now be a better option than the SpacePak that has a variable speed motor. It may not even require as much return air, which would mean they won't have to punch a hole in one of our bedroom ceilings. I will need to figure out how to evaluate that option...I know this isn't the place for that since it's not geo.

Sure it is part of the geo system. Reduced airflow will increase the refrigerant temperature and pressure, which will put unneeded stress on the equipment and make is inefficient. It is a matter on how the SYSTEM works together, not each individual part for itself.

Posted By docjenser on 27 Aug 2013 08:20 PM

Posted By tamar on 26 Aug 2013 10:52 AM
I had not thought of that....good point. I know the blower motor was toast, as it sounded like a freight train and was hiccupping and chugging. Replacing it was like night and day. This was during heating season. The TXV supposedly failed during the hottest days of summer last year, and it took 3 weeks to get a replacement because it is soldered to a coil (or so I was told). It was my first month working from home and it was miserable. There may now be a better option than the SpacePak that has a variable speed motor. It may not even require as much return air, which would mean they won't have to punch a hole in one of our bedroom ceilings. I will need to figure out how to evaluate that option...I know this isn't the place for that since it's not geo.

Sure it is part of the geo system. Reduced airflow will increase the refrigerant temperature and pressure, which will put unneeded stress on the equipment and make is inefficient. It is a matter on how the SYSTEM works together, not each individual part for itself.

I continue to learn, but continue to be naïve about some of this. I haven't seen any discussion of HV equipment in this forum, so figured it should be discussed somewhere else.

I can't believe it has gotten to this point, but today I threatened legal action and initiated a dispute on Angie's List (which is free) and NOW I hear that there might be some movement towards a proposal to initiate a fix. Based on Joe's comment that we'd need to reduce capacity to reduce the requirement for return air, and your advice, Doc, that reduced airflow puts additional stress on the equipment, it sounds like they will be punching a hole in the ceiling of our 2nd bedroom. After the last few days in MN, less effective A/C is the last thing I want.

Thanks for your continued advice and support!

I finally got installer's attention and I think they may understand the importance of communication going forward, so that is good. Unfortunately, their communication this morning indicates that they are still investigating using the split as the first stage of heat. I don't recall anyone here endorsing that idea when we've got the option of high temp hydronic. Are there any new thoughts on that (or anyone want to reiterate their previous thoughts?)

Probably some more details around the time you wrote this:

> So, the WtA geo is most efficient, and we will run that as our first stage

Posted By jonr on 28 Aug 2013 10:54 AM
Probably some more details around the time you wrote this:

> So, the WtA geo is most efficient, and we will run that as our first stage

Thanks, I found some info around April 13-20.

Water to water at lower supply temperatures has higher efficiencies, so we use them as first stage.
Only during cold spans we have sometimes second stage coming on, whether it is supplement forced air, an air handler, etc.
In addition, what is the purpose of radiant if you don't use it most of the time?