Posted By lomax0990 on 01 Dec 2013 01:12 PM

... 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.
 
... the manual for the Tranquility 27 said the compressor will shut off after 4 hours of run time to protect the compressor. ... 

If it was me living in a structure identical to yours at your location, and was observing heating conditions as you describe, and was looking for some time to further learn on this DIY installation, based on my experience and knowledge, at this point I would:

1. Reduce the tstat to a maximum high of 68 degrees;
 
2. Remove any setback tstat settings;

3. Remove any manual adjustments you may have done to the Tranquility 27 - i.e., let it run per manufacturer default settings (including allowing the compressor to cycle off/on after 4 hours if indeed it's supposed to).

and see if your situation improves.

If it doesn't, and the family situation allow for it, I'd reduce down another degree or two.

Maybe your loop capacity is such that a drop of 2° F of the tstat setting (from 70 to 68°) is enough to give the loop field enough time to recover during sunny daylight periods (where solar energy is contributing enough to the structure such that the heating unit doesn't have to run for at least a while.

In an economical manner, it just isn't possible to pull out heat from earth at the same rate or slower that the heat can be replaced by the earth.  The heat just doesn't move quickly enough in the earth.  So the loop needs recovery time, on an instantaneous basis.

Here's a chart that illustrates this point: http://www.welserver.com/perl/plot/...mpsEWT.png .  This is a complicated chart and usually requires some study to understand.  Key point here is that as heat is drawn out of the earth at a rate of 40 kbut/hr or greater, EWT drops. 

Once you have your pressure gauge, can measure loop water delta-T, know what your antifreeze level is, and can compute heating capacity (kbtu/hr) of the geo loop, you'll be able to compare this to the claimed heat capacity of your 4 ton unit, and will be able to make some progress narrowing down where the problem may be.

1. Measured heat capacity not approximately equal to manufacturer spec?  You've got work to do on figuring out how to improve/fix the performance of the HVAC system.  You've got a design problem or a non-performing piece within the system.

2. Measured heat capacity approximately equal to manufacturer spec? Your heating system is not the problem. 

If 2.) is 'yes,' then:

3. Measured heat capacity approximately much less to approximately equal to heat load of structure?  You've got a structure problem, ranging from not enough insulation to a big hole to the outside somewhere.

4. Measured heat capacity approximately higher to much higher than heat load of structure?  You've got a problem with your analysis.

DIY offers tremendous opportunity for cost savings on geo HVAC residential efforts.  But absent putting in the time doing the above design and engineering work in advance of installation, it's been my observation that it's a 'crap shoot' as to whether or not the geo HVAC system will work.

I think your choices are to:
1. Spend the time to learn and to understand the design of your system (including the heat loss characteristics of your structure)
2. Bring in someone who is expert with geo systems (not very easy in many cases)
in order to put together an action plan. 

If you don't have the time to learn and understand ..., and/or have a family situation that can't handle keeping the tstat at 67, 66, 65 etc to give you time to learn and figure out what's going on, then you'll have to find/pay for an expert to help you put together an action plan in a much shorter time frame.

If you want to eliminate the risk of finding an expert, consider spending $2-4K by offering to fly in an expert who contributes here on this forum where you have plenty of opportunity to assess capability before making offer.  About $1K for travel plus paying for a day or so of consulting, resulting in an action plan that you can return to DIY mode an implement, but this time with confidence that your design is good.

My guess is action plan is one of 5 things to go attack, or possibly a combo:
1. Something's broken and needs replacement (not my guess)
2. Airflow is restricted or not implemented properly (i.e. poor duct work design or implementation)
3. Water flow is restricted or not implemented properly (i.e a manifold configuration problem)
4. The geo unit's not running at capacity and/or EWT is very cold because system is 'starved' for loop field capacity (i.e. you need more pipe).
5. The geo unit's running flat out and at performance (i.e. 1900 sf structure is just not well insulated enough).

Hope this helps.

Best regards,

Bill

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.

arkie6,

Ok so going off of a0128958 suggestions about building an action plan I think the first one I may try to tackle is the insulation issue. Since you know more about insulation than I ever could I'd like to run these action items by you.

1.) I'm not sure the cost (my budget is somewhat limited till we recover from building the house), but I know there are different options to put holes in the drywall and spray either an open cell foam or some fiberglass insulation into the wall cavities. I will begin to research the idea of doing something like that. Do you recommend one insulation type over another?
2.) I just measured and after settling the blown in insulation in the attic is 9-10" beep. So I can get a couple more inches blown in the attic relatively easy.

Does that sound like a good plan of attack?

My guess is action plan is one of 5 things to go attack, or possibly a combo:
1. Something's broken and needs replacement (not my guess)
2. Airflow is restricted or not implemented properly (i.e. poor duct work design or implementation)
3. Water flow is restricted or not implemented properly (i.e a manifold configuration problem)
4. The geo unit's not running at capacity and/or EWT is very cold because system is 'starved' for loop field capacity (i.e. you need more pipe).
5. The geo unit's running flat out and at performance (i.e. 1900 sf structure is just not well insulated enough).

a0128958,
Thanks for the thoughts. I like the action plan. Unfortunately my situation doesn't call to lowering the temp much (4 month old in the house). So from above I'm hoping to focus on what seems to be the quickest things to eliminate, your numbers 3 and 5. Once I get the pressure gauge I will try to calculate the heating output and hopefully that will provide you guys with more insight into #3. As far as #5 I'm going to begin research into that as discussed above.

If you don't have the time to learn and understand ..., and/or have a family situation that can't handle keeping the tstat at 67, 66, 65 etc to give you time to learn and figure out what's going on

I would like to understand the system better just so I have the knowledge is something goes wrong in the future. I'm just hoping the kind folks on here are willing to be patient and help me.

Currently i'm only running the heat strips to heat the house up a few degress so I can give the compressor a break. So I dont' think i'm going to be breaking the bank on running the heat strips. Granted it's not as cold as it will get in the dead of winter. Hopefully I can get by as I try to improve on some of the deficiencies that have already been brought up in this thread.

Posted By lomax0990 on 01 Dec 2013 05:38 PM

... I would like to understand the system better just so I have the knowledge is something goes wrong in the future.  ...

Currently i'm ... running ... heat strips ... so I can give the compressor a break.

The WEL is perfect for individuals like yourself.  The $600 investment (total, include temp sensors), with never a monthly fee, will pay off in incredible fashion, with the amount of information and status that you can then study 'till your heart's content.'  If it was me, I'd get this installed ASAP to start giving you the opportunity to gain the knowledge you want.

To help you gain some time to study and learn, while being able to simultaneously maintain 70° for the whole winter, I recommend:

1. Put the tstat at 70° with no set back and let the Tranquility internal electronics to do its job (4 hour compressor cycles).  Let the Tranquility "give the compressor a break" - it will be able to do this more efficiently than you can manually.

2. Turn off Stage 2.  The faster you remove heat from the earth the more expensive it's going to be to heat your structure later in the dead cold of winter season.

3. Set your heat strips up to turn on automatically as needed.  Let your tstat do its job.  Set tstat (how long unit is allowed to run before Aux Heat is turned on) such that Tranquility can sit at rest during x number of hours each day to give your loop field a chance to recover.

At this point I don't believe you have a zero cost recovery option.

Minimum cost will be the electricity needed to run the heat strips.  If it was me my next expense would be the WEL.  Knowledge is power - putting in insulation to the walls, while it may sound right, isn't your highest priority (lowest cost action) if your HVAC system has a design or operational problem.

Best regards,

Bill

Have a blower door whole house air infiltration test done.

If some or all of ductwork is in unconditioned space, have ducts tested for leakage.

Gross air leaks (house or ducts) trump insulation levels.

The low airside delta T suggests cold air leaking into return - easy to infer - measure air temp right where it enters system. If that is much (~2*F) below house air temp, cold air is leaking into return.

While I agree a bit more water flow may help, 41*F EWT and 31*F LWT are well within range to get good heating performance. Of course, the situation may (will) change by late January.

Posted By lomax0990 on 29 Nov 2013 07:59 PM

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.

Fire your technician. Closed loopfield flow should never been restricted to get higher delta T. So you put in 2 pumps in the flowcenter, and you pay for the increased pumping power and flow, only to close the valve to reduce flow more?
So get the valves open, and do not put in any flow restrictors. How long is each circuit, and how many circuits do you have?
Constantly running in stage 1 is normal at an outside temp of 25-30F, especially in your area. Yes, Climatemaster is odd by disengaging the compressor every 4 hours for a minute or so, other manufacturers don't do that. never made sense to me. Nor does it make any sense to shut it off to allow the loop to recover. A well designed loop does not need to recover, but stabilizes around 30F.
So it appears so far that your system runs normal, just eliminate the flow restriction in the loopfield (open the vales back up to get back to a 5 degree delta t) and don't set back the thermostat. The system is designed to maintain temperature very efficiently, but not to increase it frequently during colder periods.

just eliminate the flow restriction in the loopfield (open the vales back up to get back to a 5 degree delta t)

All the valves have been opened fully back up.

How long is each circuit, and how many circuits do you have?

5 circuits at 600ft a piece.

Yes, Climatemaster is odd by disengaging the compressor every 4 hours for a minute or so

I'll have to read the manual, but it seems mine is off longer than a minute.

Thanks again to everyone for their help. I got a pressure gauge today and here are the updated figures that I just took:

EWT : 39.2
LWT : 36.1
EWP : 18psi
LWP : 12psi

Those numbers were on stage 1. When I turned on stage 2 I got a couple more degrees delta. The LWT on Stage 2 was 34.7. As a0128958 has previously suggested I think I have everything I need to do the kbtu calculations now. I will read back and as soon as I figure out that information I will check that against the manufacturer specs.

Posted By lomax0990 on 02 Dec 2013 08:06 PM

EWT : 39.2
LWT : 36.1
EWP : 18psi
LWP : 12psi

Good job.  You're making progress.

Get the Spec Manual out for your unit and start reading.

Your Delta-P is 18 - 12 = 6 psi.  Find the chart that translates Delta-P to gallons per minute.

Then find the formula in the manual for computing heating capacity (kbtu/hr).  Assuming for a moment you have water (i.e. in the formula you'll find assume constant is 1.0), you have all the numbers you need to make a calculation.

Next find out how much antifreeze is in your loop water.  (I don't know how to do this - no such thing as antifreeze in the Dallas area for geo loops, and thus I never had to learn how to measure how much antifreeze is in water.)  And then translate this amount to adjustment of the formula constant (I don't know how to do this either since the value of 1.00 is good for plain water).

Last step is to redo the heating capacity calculation using the constant that represents how much antifreeze is in your loop water.

Look up what kind of heating capacity you should have at your EWT, water flow and air CFM conditions.  And then compare to your actual measurement.  At this point you finally have a 'figure of merit' (the comparison of what you calculated to what you looked up) to give you a reasonable conclusion on if your system has a problem.

My guess is your heating capacity spec for first stage is somewhere around 4 tons * 12,000 btu * 2/3, plus or minus adjustments for actual operating conditions.

Noting you've got about 3000 feet of slinky in the ground for a 4 ton unit, my further 'out on a limb' 'troubleshoot from the Internet' guess is your unit is fine, and that it simply can't offset the heat loss of the structure.  I.e., maybe indeed you can get on with insulating those walls.  At least, though, you'll have a well thought out and quantified analysis to support spending money on the structure instead of the geo unit, versus doing it based on guessing.

Best regards,

Bill

I think 6 psi reflects around 13.6 gpm at your watertemp. First stage heat extraction is 20,450 btu/h, spec says it should be 20,300 btu/h. Your heatpump performance is right on. Your loop is at a good temperature, and your balance point for the house is between 25F and 30F. looks to me like a system right on the money.

At least, though, you'll have a well thought out and quantified analysis to support spending money on the structure instead of the geo unit, versus doing it based on guessing.

Yeah i'm going to begin research into adding some more insulation into the walls. And I will get some more blown into the attic. I've still been researching the WEL system, and will probably purchase that when I can. Unfortunately all our disposable income has been going back into finishing the house.

looks to me like a system right on the money.

Ok this has been exactly the information I've been needing to understand. If the system was performing as it should or if I could improve it. Sounds like it's performing within specs and I can try to add some insulation to decrease my balance point.

Thanks to everyone who contributed to this thread for their help and patience with my ignorance. Just one last question and I'm done. Are the PSI readings given above about what is to be expected? I did some quick reading last night and got the impression that maybe those readings should be a little higher?

Now you want to do the same thing focused on the structure: quantified analysis to guide you to optimal spending.  I.e. what do you spend your money on toward the structure, and what's the 'bang for the buck' for each possible action.  I.e., a prioritized list in order of most to least economic gain.

There's plenty of material out in Internet land that will be helpful; there's 100X more that won't be.

Some suggestions to be efficient with your time:

1. Go do what Curt Kinder suggests WRT doing a duct work blower test and a structure blower door test.

Since you have a 4 ton properly functioning unit that can't keep up on any day in first stage for a 1900 SF structure, you may find that while your HVAC equipment is working fine, the heated air isn't all being delivered to the conditioned part of the structure interior.

Secondly, WRT the structure, continuously proven, clearly, you'll get a larger 'bang for the buck' by  focusing first on air infiltration versus insulation.  If the duct work blower test doesn't show any problems with the ducts substantially leaking, I'd then get the structure blower door test done ASAP.  Now you'll have a 'blueprint' for actions to take to make the structure more air tight.  Who knows - you may even discover some big hole you've got that substantially accounts for why a 4 ton properly functioning system in first stage can't satisfy the heat load of a 1900 SF structure.

2.  Get familiar with Manual J and determine what the heat load is for your structure.  In the process of doing this you'll learn the tradeoffs of attic insulation versus exterior wall insulation versus amount of glazing versus quality of windows/doors versus etc.  Once you've learned the tradeoffs you can make better, more informed decisions on what to spend your money on such that you do the 'big bang' actions first.

3. Get going planting (more) trees outside such that in 5 - 10 years you'll start getting some shade benefit.  The journey of a thousand miles starts with a single step.  Don't plant them such that south exposed roof area will some day be shaded - someday you'll want to put up solar panels.

4. From a family comfort point of view, and to keep the geo unit compressor from running endlessly, you could consider temporarily reducing air volume flow to rooms that are not as used as much, in order to increase air volume to frequently used rooms.  This may help with raising the heat temp in the frequently used rooms.

5. I'd skip for now other subjects like HVAC air duct zoning, radiant barrier, removing incandescent bulbs, etc. and focus your time on finding the 'big hitters' for air infiltration and insulation.  

6. If you have powered attic air exhaust fixtures I'd turn off the power to them.

Good luck!

Best regards,

Bill

To find local Home Energy Raters (HERS) that can perform home energy audits and testing, check out the following site:

http://www.resnet.us/trade/home-energy-raters-hers-raters

A new set of experienced eyes looking at your duct work and building envelope might find some easy and low cost fixes that we just can see via the internet.

Posted By lomax0990 on 03 Dec 2013 09:33 AM

At least, though, you'll have a well thought out and quantified analysis to support spending money on the structure instead of the geo unit, versus doing it based on guessing.

Yeah i'm going to begin research into adding some more insulation into the walls. And I will get some more blown into the attic. I've still been researching the WEL system, and will probably purchase that when I can. Unfortunately all our disposable income has been going back into finishing the house.

looks to me like a system right on the money.

Ok this has been exactly the information I've been needing to understand. If the system was performing as it should or if I could improve it. Sounds like it's performing within specs and I can try to add some insulation to decrease my balance point.

Thanks to everyone who contributed to this thread for their help and patience with my ignorance. Just one last question and I'm done. Are the PSI readings given above about what is to be expected? I did some quick reading last night and got the impression that maybe those readings should be a little higher?

If anything the psi is a bit too high, meaning that you are pumping more water through it than needed. Not much you can do about it, unless you want to take one pump out of the flowcenter, which should save you about $80/year in pumping costs. Other than that, your geo system is optimal. The rest is up to the house.

Do both loop pumps run in first stage and second stage? If so, can you configure the flow center to run one pump in first stage, and both pumps in second stage? Do you have the standard QT2 pumps (UP 26-99F @ 1.07A each) or the optional higher capacity UP 26-116F pumps @ 1.8A each? Being able to shut down one of the smaller pumps will save you ~5.7 KWH per day or ~170 KWH per month assuming continuous operation and 0.97 power factor @ 1/6HP. Being able to shut down one of the larger pumps will save you ~9.6 KWH per day or ~290 KWH per month assuming continuous operation. Assuming electricity at $0.10/KWH, that's a savings of $17 to $29 per month.

Do both loop pumps run in first stage and second stage?

Yes both pumps are wired in series to the T2 terminal in the unit that turns the pumps on when the compressor kicks on.

If so, can you configure the flow center to run one pump in first stage, and both pumps in second stage?

I would love to do this as long as you don't think it would effect the performance. Only thing is off the top of my head I don't know how that would be done. I thought the T2 terminals were the only hot terminals I could use when the compressor kicks on. That being the case I don't know how I would differentiate between stage1 and stage2.

Do you have the standard QT2 pumps (UP 26-99F @ 1.07A each) or the optional higher capacity UP 26-116F pumps @ 1.8A each?

I have the standard UP 26-99F's.

docjenser,

First stage heat extraction is 20,450 btu/h, spec says it should be 20,300 btu/h. Your heatpump performance is right on.

My PSI readings seem to be the same on Stage 1 or Stage 2 Operations. The specs in the manual say "Full load" (which i'm assuming is stage 2) should be 28,000. Based on the formula for Heat Extraction (HE = TD x GPM x 500) either the Temp Delta will need to increase or the PSI would need to increase? Earlier it was suggested to open the valves up all the way which is giving me around 4 or 5 degress temp delta. With my temperature delta being the same and the PSI readings being the same on stage1 and stage2 I can only assume that I'm still only extracting around 21,000 btu/h. When I should be seeing around 28,000 btu/h. Am I off base here?

Posted By lomax0990 on 03 Dec 2013 08:29 PM
docjenser,

First stage heat extraction is 20,450 btu/h, spec says it should be 20,300 btu/h. Your heatpump performance is right on.

My PSI readings seem to be the same on Stage 1 or Stage 2 Operations. The specs in the manual say "Full load" (which i'm assuming is stage 2) should be 28,000. Based on the formula for Heat Extraction (HE = TD x GPM x 500) either the Temp Delta will need to increase or the PSI would need to increase? Earlier it was suggested to open the valves up all the way which is giving me around 4 or 5 degress temp delta. With my temperature delta being the same and the PSI readings being the same on stage1 and stage2 I can only assume that I'm still only extracting around 21,000 btu/h. When I should be seeing around 28,000 btu/h. Am I off base here?

You are getting there. First the heat extraction factor for water with antifreeze is 485, not 500. Flow does not change whether the unit is in 1st or 2nd stage. What changes is the delta T, meaning that it takes more heat out of the water and increases your LWT, which you said yourself went up by 2 degrees in second stage.

Posted By lomax0990 on 03 Dec 2013 06:59 PM

Do both loop pumps run in first stage and second stage?

Yes both pumps are wired in series to the T2 terminal in the unit that turns the pumps on when the compressor kicks on.

If so, can you configure the flow center to run one pump in first stage, and both pumps in second stage?

I would love to do this as long as you don't think it would effect the performance.

You are currently flowing ~13.6 GPM with both pumps.  The full load requirement for your 4 ton unit is ~12 GPM (3 GPM/ton).  In first stage, you should only need 2/3 x 12 GPM = 8 GPM.

A few posts back it was mentioned that EWT = 39.2 and LWT = 36.1 in first stage (delta T = 3.1) and in second stage the LWT = 34.7 (delta T of 4.5). This shows second stage is removing ~50% more heat from the loop water than first stage.  Since first stage is ~2/3 of the 4 ton rating, that looks right on the money.

Second Stage:
HE = TD x GPM x 485.
HE = 4.5 x 13.6 x 485 = 29682 BTU/h

In first stage, you should only need 2/3 x 12 GPM = 8 GPM.

I don't want to take up any more of your time but if could you point me in the right direction of how to wire 1 pump for stage 1 and both pumps to run on stage 2 I would greatly appreciate it. I can't seem to find much on the web or in the manual for the QT center. I haven't had a chance to ask my electrician who wired up the pumps, but I thought if I had some idea that would help.

That is for sure my last question. Thanks again to everyone for there help and patience.

easiest thing to do would be to break one wire to the pump with a relay. That relay could be closed by 24 volts when Y2 was energized.