I'm trying to get some feedback from some experts regarding tuning/troubleshooting my Tranquility 27.  I installed the system myself (even though I shouldnt' have).  I'm not an HVAC expert, just a hobbyist who likes to learn new things.  I've had our local ClimateMaster dealer out a few times, but unfortunately I don't believe the technicians are as knowledgeable as the folks on here.  My goal here is to get the system operating as efficiently as I can and try to learn things in the process.

Here are my main questions/concerns:

1.)  The heat pump seems to be able to barely keep up during current temps. It seems like it can keep the temperature the thermostat is set on, but if I don't do anything the pump runs nearly all day.  Mostly on Phase1 and sometimes going into Phase2.  Now I bump the thermostat up to kick in the AUX heat so I can get the temp up so I can shut the pump off for periods of time.  Obviously, going into AUX heat is killing the performance of the system.  Currently it's been about 30F during the day dropping to 15 or so at night. 

2.)  I'm measuring the temp at the return air ducts at 73/74 degrees and an outlet register close upstream at 89.  Which is a difference of about 16.  From what I can understand it seems that number should be closer to 20 or 25??


I looked at the "where to start thread" and I will try to answer as many as those questions as my knowledge will allow:

1.)  Where you live : West Virginia
3.)  Brand/Size/Model Heat Pump : ClimateMaster Tranquility 27 4 Ton
4.) Type of Loop : Horizontal with 5 slinky loops with a QT flow center
7.) EWT/LWT : Currently EWT=41 LWT=31 (measured directly at the unit)
Misc.)  The house is fairly well insulated.  It has 2" of spray foam on exterior walls and blown in insulation in attic.

This may be a little late in the game, but based on your description, your home doesn't sound that well insulated. Is 2" of spray foam all you have on the exterior walls? Is it closed cell foam (hard) or open cell foam (soft)? I assume these walls are 2x4 stud framed walls? Do you have any rigid foam board for exterior sheathing? If so, what type and how thick?

Assuming you have 2x4 walls with studs at 16" on center, the wood framing comprises approximately 25% of your wall space (this includes studs, bottom plates, double top plates, extra studs around windows and doors and headers, extra studs at corners, extra studs at intersecting walls, etc.). Assuming you only have 2" of closed cell foam (aged R value ~6.5/inch) in the stud cavities, your whole wall R value is only approximately 6.5 when you factor in the wood framing (~R1.25/inch).

1/(R Total Wall) = 1/(2 inch x R1.25/inch x 0.25) + 1/(2 inch x R6.5/inch x 0.75)

Given the above assumptions and equation, R Total Wall = 6.34.

A big issue here is that you only have 2" of insulation in a 3.5" cavity.  This effectively reduces the already poor insulating property of the 2x4 stud from 3.5" to the 2" thickness of the insulation.  The stud is providing an R2.5 path in parallel with the R13 cavity insulation.  If you had a full 3.5" cavity thickness of R13 insulation (say open cell spray foam or spray applied cellulose), then you would have the full 3.5" x R1.25 or ~R4.5 in parallel with the R13 in the cavity.  This would bring your whole wall R value up to around R9.0 or ~50% higher than just having 2" of insulation in the cavity.

What type and how much blown in insulation do you have in your attic?

What type of windows and doors do you have?

How many square feet are heated/cooled by that 4 ton heat pump?

Regarding your heat pump, running for long periods of time in first stage is a good thing if it is close to design conditions and it is maintaining the temperature. Frequent starting and stopping of the compressor and fan motors (typical of single stage heat pumps) wastes more energy than letting it run for long periods in first stage because each time the compressor motor starts, it pulls approximately 5-6 times more current than its rated running current (motor inrush).  This includes starting the fan and loop water pump(s) also.

I don't see anything way out of whack with your water or air temperatures, especially if those supply and return air temperatures were measured with the unit running in first stage.

Another thing. Your thermostat may not be setup properly. I know some thermostats have a provision to kick the heat pump into second stage if first stage hasn't satisfied the set point in X amount of time. This feature may not be enabled on your unit or it may be set for several hours time.

Is 2" of spray foam all you have on the exterior walls? Is it closed cell foam (hard) or open cell foam (soft)? I assume these walls are 2x4 stud framed walls? Do you have any rigid foam board for exterior sheathing? If so, what type and how thick?

Yes 2" of closed cell spray foam is all we have. Maybe I was misinformed, but the spray foam company basically said most of the insulating value is in the first two inches. And yes they are 2X4 stud framed walls. Just the exterior house wrap on the outside. The house is all brick which I think provides some insulating value???

What type and how much blown in insulation do you have in your attic?

I dont' know the R value but I think it's blown in celluose about 6" inches thick.

What type of windows and doors do you have?

New Simonton double pane windows with the argon gas.

How many square feet are heated/cooled by that 4 ton heat pump?

We have about 1900 sq ft being heated by the heat pump.

Regarding your heat pump, running for long periods of time in first stage is a good thing if it is close to design conditions and it is maintaining the temperature. Frequent starting and stopping of the compressor and fan motors (typical of single stage heat pumps) wastes more energy than letting it run for long periods in first stage because each time the compressor motor starts, it pulls approximately 5-6 times more current than its rated running current (motor inrush). This includes starting the fan and loop water pump(s) also.

I know it's not good for the unit to short cycle. However, when you say running in long periods in first stage, does this include 20+ hours? For example, if I just left the unit on 70 I think it would run practically all day in first stage. But, I think I read in the manual that the compressor will kick out after 4 hours as a safety mechanism. What I can't understand though, is that even when it does switch to second stage, it just doesnt' appear to be able to raise the temperature any, because it still runs almost nonstop. It just seems like on 1st or 2nd stage it can only maintain the temperature and not increase it.

Another thing. Your thermostat may not be setup properly. I know some thermostats have a provision to kick the heat pump into second stage if first stage hasn't satisfied the set point in X amount of time. This feature may not be enabled on your unit or it may be set for several hours time.

I've suspected there may be something I can do at the thermostat to help this issue. Although I haven't yet sat down to figure out what that may be. I guess in the back of my head I keep thinking there isn't. The thermostat is a Pro1 IAQ T925.

I'm no expert by any means but 4 tons for a 1900sf house is HUGH! You say 5 slinkys, how many feet? Did you get quotes from HVAC experts first?

Posted By lomax0990 on 27 Nov 2013 09:51 PM
...
1.)  Where you live : West Virginia
3.)  Brand/Size/Model Heat Pump : ClimateMaster Tranquility 27 4 Ton
4.) Type of Loop : Horizontal with 5 slinky loops with a QT flow center
7.) EWT/LWT : Currently EWT=41 LWT=31 (measured directly at the unit)

How did you determine how much HDPE pipe to install, and at what depth?

Is it possible you did not install enough pipe into the ground?  Or put it deep enough?  I.e., your 4 ton geo unit can't get enough heat out of the earth at a fast enough rate?

Best regards,

Bill

I'm no expert by any means but 4 tons for a 1900sf house is HUGH! You say 5 slinkys, how many feet?

A couple corrections there: We also have a bedroom and an office in the basement that have runs into those room. We also put a run out into our garage. 2 of those 3 are blocked off right now though. So it's probably closer to 2100-2200sq ft.

Did you get quotes from HVAC experts first?

Unfortunately there is only one HVAC company doing geothermal in my area. They wanted 30K to install the system and that was with me providing the excavation work. So it was to tempting to do myself when I'm looking at a 10-15k cost savings. In there quote they basically quoted me the 4ton system. However, I tried to do as much research as I could and not just taking there word for it. From everything I could find I was in between a 4 and 5 ton. I thought with the spray foam insulation I could get by with the 4 ton.

How did you determine how much HDPE pipe to install, and at what depth?

I went off recommendations from the company I bought the furnace from. I also found a few folks around the web who had installed systems and asked them questions trying to determine the amount of piping. I ended up going w/ the 5 slinky loops at 7ft. About 10 ft before they enter the basement they come up to a depth of about 4 ft.

Is it possible you did not install enough pipe into the ground? Or put it deep enough? I.e., your 4 ton geo unit can't get enough heat out of the earth at a fast enough rate?

Yes anything is possible. Like I said I educated myself as much as I could before attempting to do the system myself, but in no means do I know nearly as much as I should. In the end I just didnt' feel the HVAC company had much more expertise than I did. So between that and the cost savings I decided to do it myself. That's partly my reason for asking questions. Trying to determine where I've gone wrong and if there is anything I can still do to improve the performance. i.e. Try partially closing input/output valves on my headers to reduce flow, etc..?

Posted By lomax0990 on 28 Nov 2013 10:16 PM

Is 2" of spray foam all you have on the exterior walls? Is it closed cell foam (hard) or open cell foam (soft)? I assume these walls are 2x4 stud framed walls? Do you have any rigid foam board for exterior sheathing? If so, what type and how thick?

Yes 2" of closed cell spray foam is all we have. Maybe I was misinformed, but the spray foam company basically said most of the insulating value is in the first two inches. And yes they are 2X4 stud framed walls. Just the exterior house wrap on the outside. The house is all brick which I think provides some insulating value???

What type and how much blown in insulation do you have in your attic?

I dont' know the R value but I think it's blown in celluose about 6" inches thick.

Your home insulation values don't even meet current energy code minimum requirements of R13 wall cavity insulation + R5 exterior sheathing and R38 in the attic.  Your home has about half as much insulation as it should have.  As I stated previously, your whole wall R value is only approximately R6.5, and that is assuming the spray foam installer gave you the full 2" and not some lesser average amount.  Properly installed R13 wall cavity insulation that fills the 2x4 stud cavity comes in at around R9.0 whole wall when factoring in the framing.  Add another R5 for rigid foam exterior sheathing, and you are around R14 for the whole wall R value per the energy code.  You only have R6.5.  Your heat loss through your walls is approximately twice as much as a code minimum home.

Blown cellulose in the attic comes in at around R3.7 per inch.  Assuming 6" of this material and neglecting the lower R value of the ceiling joists / truss bottom chords, your attic R value at best is only 6 x 3.7 or R22.  You should have at least 10.5" of blown cellulose in the attic after settling for R38.  Again, your heat loss through your attic is almost double what a code minimum home should have.

How much attic R value did you pay for?  It looks like your insulation contractor short changed you all the way around.  At least in the attic, you can add more cellulose without too much cost or additional effort. 

These low insulation values are at least part of the reason your heating system isn't performing as well as you would like. 

Spray foam companies are notorious for those statements of 2" in the walls and 3" on the ceiling is all you need because it helps sell their product.  If you installed the proper amount, the cost would be prohibitive and they would lose sales.  Spray foam costs ~5x more than the equivalent R value of sprayed cellulose.

US residential brick provides little if any insulating value because it is mostly solid and has too many low R value cement mortar joints that bridge across them.  Also, the brick should have a minimum 1" vented cavity behind it, so it effectively provides no insulating value.  The mass of the brick veneer should provide some thermal lag, but that is about it.

It would probably be a good idea to get set up so that you can measure flow through the loop. Once you know flow and temperatures, you can get a good idea of the btus being extracted and compare it to the manufacturer specs (in the manual). But it could well be that you just need more insulation and air sealing.

Posted By lomax0990 on 29 Nov 2013 10:58 AM

... Like I said I educated myself as much as I could before attempting to do the system myself, but in no means do I know nearly as much as I should.
 
In the end I just didnt' feel the HVAC company had much more expertise than I did. So between that and the cost savings I decided to do it myself.   ...

The number of companies doing geo in the Dallas area has slowly declined over time.  They found that it was tough to get properly working geo systems in the intense heat we have here, just based on their traditional conventional HVAC skills.  Many learned there's much less room for design error on the geo side than with conventional A/C, and, absent having good geo expertise and the right design tools (i.e. just guessing or using 'rules of thumb' or just asking what others would suggest), more often than not their geo implementations didn't work (down here the definition of 'not working' is not enough cooling in the summer time).

So even in a big metropolitan city area, it's not unusual for the residential home owner to have more expertise than many of the geo HVAC firms.  Geo doesn't have to be non-performing, and doesn't have to be exorbitantly expensive, but, to do so requires expert design.  The need for expert design with much less room for error I believe is the single most market limiting item for geo at the residential level.

In your case:  lots of discussion could be engaged on what you should have done, etc.  But, it doesn't take away from the fact that you've got what you've got.  Your questions are probably:
1. Have I done something wrong that can easily be corrected?
2. What do I need to do to have a well performing geo system?

Since you're not afraid of the risks of doing things yourself, and, since you like to learn, I recommend you:
1. Learn as much as you can about how your system is operating
2. Provide as much actual operational detail as you can to others who will gladly help you here.

To do so, I recommend you invest into 2 things:
1. A Web Energy Logger (your DIY actual materials cost at about $600 - just purchase temp sensors).
2. An easy to read pressure gage (like this one).

These, plus published operational data for your ClimateMaster unit, will enable you to understand all of the thermal characteristics of your system to then pinpoint where you have problems.  (Add about $300 if you want the WEL to compute for you actual COP and EER to then compare to manufacturer specifications - you'll need to put in power monitoring).

An example of a WEL implementation for a geo system is here for my residence: http://www.welserver.com/WEL0043 .

Also, docjenser, a frequent poster, is expert with WEL implementations, as he has about 25 running out in the field.  I'm sure he'll point out some examples.

And, there are many example implementations listed here:  http://www.welserver.com .

While installation time for WEL hardware is just a few hours at most, it will require a moderate amount of time to learn how to configure the WEL to get the information you need / want.  It's not hard, but, like anything new and different, there's a learning curve.

You need the gage, in conjunction with the WEL's temp readings, to ultimately determine KBTU/hr that your system is bringing in to your structure.  Assume your airflow is as set with the ECM blower fan.

Good luck.

Best regards,

Bill

It would probably be a good idea to set up your heat pump so that you can measure flow through the loop. Once you know flow and temperatures, you can a good idea of the btus being extracted and compare it to the manufacturer specs.

So here is why my ignorance comes in. I'm not exactly sure how to measure the flow. How can I measure it through the loop? At the P/T ports at the furnace?

This or this looks good.

We have them in about 5% of our systems, a total of about 25 Welservers. Only the interesting ones…. In response to the original poster here, your flow is way to low, you should see about 5 degrees difference between the incoming and outgoing water, not 10 F. How is your pumping to and from the loopfiled configured, and your pipe, and your loopfield itself? What is the diameter of the pipes going out, and the pipes of the loopfield?

In response to the original poster here, your flow is way to low, you should see about 5 degrees difference between the incoming and outgoing water, not 10 F

The HVAC technician said I should shut the valve on the outgoing side to slow the flow down to get closer to 10F on stage 2. I can open it back up and it was running about 5-6F delta on both stages. Should it be 5 degress difference on both stages?

How is your pumping to and from the loopfiled configured, and your pipe, and your loopfield itself? What is the diameter of the pipes going out, and the pipes of the loopfield?

The pumping is done from a dual pump QT flow center. The pipe going out to the loopfield is 1 and 1/4 PVC. From the QT flow center it is 1" rubber hose to the furnace. The loopfield is 3/4 HDPE in slinky loops.

As I stated previously, your whole wall R value is only approximately R6.5, and that is assuming the spray foam installer gave you the full 2" and not some lesser average amount.

arkie6,

So everything I've read says spray foam is about R6 per inch? Is that incorrect? I don't want to stray to far from the topic because unfortunately I can't go back and add another inch of spray foam. I am going to go up into the attic today and get a better idea of how much blown in there is. If there is less than 11" I will look into more insulation in the attic. My question is should I just add more blown in? Or is there a better alternative?

2. An easy to read pressure gage (like this one).

a0128958,

Thanks for the advice. I have ordered the pressure gauge.  I will update this post with the readings as soon as I get it. I'm also researching your suggestion on the WEL server. Looks like a daunting task for a beginner.

So everything I've read says spray foam is about R6 per inch? Is that incorrect? I

Arkie has tried explaining (twice) what the problem is with your WHOLE WALL insulating properties. Were there no building or code inspectors looking at your plans or insulation installation?

Posted By docjenser on 29 Nov 2013 06:27 PM
We have them in about 5% of our systems, a total of about 25 Welservers. Only the interesting ones….

I edited my earlier post to match up to this.  Thanks.  Bill

I don't even know where to start.......
First when you get within 10-15 degrees or so of your balance point the equipment should run about a hundred percent of the hour. Within 20 degrees it may still run 70-80% of the hour.
Your geo education is limited and the company you purchased the equipment from did little to help.
The system is made to run in first stage and if it begins losing ground, second and eventually third stage kicks in. If gap between set point and actual temps closes unit ramps back down to first stage thus unit keeps running and running......as it should.
Measure entering and leaving temps at the unit not at the registers.

Posted By lomax0990 on 29 Nov 2013 07:59 PM

The HVAC technician said I should shut the valve on the outgoing side to slow the flow down to get closer to 10F on stage 2. I can open it back up and it was running about 5-6F delta on both stages. Should it be 5 degress difference on both stages?

While you're waiting for your pressure gauge to arrive, you can:
 
1. Get familiar with how to measure heating capacity (kbtu/hr):
a. Find and understand formula to compute kbtu/hr.
b. Find and understand pressure-drop-to-water-flow chart as provided from ClimateMaster in the unit's technical documentation.
c. Find out how much antifreeze is in your loop water (needed as a calculation parameter).
d. Practice measuring delta temperature across your ClimateMaster's heat exchanger (measuring EWT and LWT and substracting the two).

(BTW implementing a kbtu/hr calculation in the WEL is very doable, and thus gives to you a logged means to study performance of your loop field.)

2. Do a rough-order-of-magnitude heat load calculation for your structure (that will provide to you a kbtu/hr number, at a given outside temp, that you can then compare to your real time readings obtained above to gain a sense for how adequate your heating capacity is relative to your structure's overall heat loss rate).

Once you have the pressure gauge and are reasonably good at computing heating capacity (kbtu/hr), then you can give yourself some 'science experiments:'
1. Heat capacity with limiting valve in full open position (1st stage, 2nd stage).
2. Heat capacity with limiting valve at a position that slows the flow down to where delta-T is 10F on stage 2.
3. Heat capacity with limiting valve at other positions.

My guess is that after doing these 'science experiments' you'll already be a lot more knowledgeable that the HVAC tech you used, and you'll find out that perhaps his instruction is not correct.

Best regards,

Bill

First when you get within 10-15 degrees or so of your balance point the equipment should run about a hundred percent of the hour. Within 20 degrees it may still run 70-80% of the hour.

joe.ami,

OK that gets back to my original question/problem. Like I said if I keep my unit on 70 with an outside temp of 25-30 it will run probably 24 hours a day. It seems to be able to keep the temp on Stage 1, but not raise it enough for the thermostat to kick it off. So it will run all day on Stage 1. And when the compressor does kick into Stage 2 it seems to do the same thing. Just keep the temperature steady, never kicking off. I guess my concern is that I'm pretty sure the manual for the Tranquility 27 said the compressor will shut off after 4 hours of run time to protect the compressor. So it seems like ClimateMaster is saying that the compressor shouldn't run for more than 4 hours at a time. But everything I'm understanding from the experts says it's normal for the unit to run basically non-stop.

I'm not trying to argue your point I'm just trying to understand. So I can try to learn and figure out if my system shouldn't be running this often how and if I an fix it. I appreciate everyone's patience.

a0128958,
Thanks again for your input. I will start doing as much reading as I can. I'm determined to learn as much about the system as I can. As I said above thanks for your patience.

Posted By lomax0990 on 01 Dec 2013 08:34 AM

As I stated previously, your whole wall R value is only approximately R6.5, and that is assuming the spray foam installer gave you the full 2" and not some lesser average amount.

arkie6,

So everything I've read says spray foam is about R6 per inch? Is that incorrect? I don't want to stray to far from the topic because unfortunately I can't go back and add another inch of spray foam. I am going to go up into the attic today and get a better idea of how much blown in there is. If there is less than 11" I will look into more insulation in the attic. My question is should I just add more blown in? Or is there a better alternative?

Yes, you are correct that closed cell spray foam is about R6 or so per inch.  But this only accounts for what is in the cavity between the 2x4 studs, plates, and other framing members.  On either side of this cavity you have wood framing members that connect directly from the exterior sheathing to the interior wall board.  This wood framing only has an R value of approximately 1.25 per inch. 

In a typical wood framed home with 2x4 walls on 16" centers, this wood framing comprises approximately 25% of the wall area.

http://web.ornl.gov/sci/roofs+walls/staff/papers/80.pdf

The total heat loss through the wall is a function of the differential temperature across the wall and the thermal conductivity of the wall or the "U" value.  You've probably seen U values on windows, a typical value being around 0.33 for double pane windows.  U value is the inverse of R value such that U = 1/R.  In the case of a window with U=0.33, the equivalent R value is 3.0.

The whole wall (I'm not considering windows and doors here) thermal conductivity, U (wall), is the sum of the conductivity of the cavity, U (cavity), plus the conductivity of the framing, U (framing), and relative percentages of each component.  In the typical 2x4 framed wall case,

U (wall) = [U (cavity) x 0.75] + [U (framing) x 0.25]

Since U = 1/R, the above equation can be converted to R value (this is similar to parallel resistance paths in electrical circuits):

1/R (wall) = [1/R (cavity) x 0.75] + (1/R (framing) x 0.25]

Using the above formula and R6.5 per inch for your spray foam and R1.25 per inch for your framing is how I arrived at your total wall R value of 6.34.  This number does neglect the R value of the interior wall board (~0.5) and exterior wood structural sheathing (~0.5), assuming you have that, and the somewhat squishy R value of air films, but virtually every wall assembly has these components, so they were neglected in this R value comparison calculation.

What hurts your case is the fact that your cavity insulation is only 2" deep and you have no exterior insulation which is series additive to the insulation in the cavity and the framing.  The problem with only 2" of cavity insulation is that the R1.25/inch framing is now effectively only 2" deep before it is fully exposed to the air in the cavity.  If you want to use closed cell spray foam, a better and less costly approach is to spray ~1" of spray foam on the interior of the sheathing for air sealing, then fill the remainder with low cost wet sprayed cellulose to fully fill the cavity.  Or better yet, air seal the exterior sheathing and skip the spray foam altogether.

Regarding your attic insulation, yes, just blowing in additional cellulose to bring your insulation level up to at least R38 would be my recommendation.  You can probably safely go up to R49 levels, but I wouldn't exceed that amount if you have a truss roof on 24" centers because you run the long term risk of sagging ceiling board due to the additional weight.  If you have a stick built roof with ceiling joists on 16" centers, then there wouldn't be any concerns with sagging ceiling board at R49 levels.  Assuming you currently have R22 in the attic, you could have an additional R28 or so blown up there for ~$0.75 per square foot.  You could DIY this for about half that, but it is a nasty, dusty job.  Most lumber yards and home centers provide free use of their insulation blowing machines if you buy a minimum number of bags of insulation.  Most if not all cellulose manufacturers list the recommended depth to R value on their websites and/or insulation bags.

What about the insulation under your basement slab?  Is this a full basement?  Is the basement conditioned?  If the basement is not a full basement and/or unconditioned, what type and amount of insulation do you have under your main level floors over unconditioned areas?  Heat loss through the floor over unconditioned areas is not insignificant.