The most useful piece of advice I can give you, is to ignore anything said in reply to this post by DNandB, aka Daveinillinois, Advicegiver4U, Hello Friend, or any of the countless other names he uses, as he is a complete HVAC Hack, who has been virtually thrown out of the professional HVAC group.
There are Professional HVAC people who reply here, who will give you help.
Hank
Hello All,
I'm hoping I can get some advice from someone out there who may have run into the scenario I'll describe. Thanks ahead of time for taking the time to read this.
I moved into a new house last spring into which we installed a geothermal heating system. The house is 3300 sq ft, lots of windows, open family room, etc. The loop is closed, in three vertical wells and the unit is a ClimateMaster Genesis Split. There is a 3 ton unit servicing the 1st floor (sized to accomodate future basement finishing) and a 2 ton unit for the 2nd floor. The refrigerant line runs to the attic where it connects to a 2 ton Trane Variable Speed Air Handler. The original contractor went out of business before the house was complete without having finished the 2nd floor system (it needed charged and checked out). I got it charged by another company and they retured to adjust it once when it tripped off in the summer.
Now, to the winter and the problems. The loop seems to be working fine
- loop temperatures and pressures are reasonable. The 1st floor unit works like a dream. We have a set temp of 72 deg and even on the recent days when it's been near zero, the unit does not run full-time and maintains temperature. The inlet air temp at a return on the floor is about 70-71 and the exit air temp at the supplies are about 95 degrees. All of this is great, except for the fact that it must be working harder to help the second floor.
My second floor air handler is running 24 hours a day and is still failing to meet the set temperature. I've checked and sealed any ductwork leaks and added additional insulation to the attic. I've got
heat to the attic because on a recent 18 degree morning it was about 19 degrees up there. If I do a heat transfer balance based on the R-values I should have and the 2nd floor temp, that was the correct equilibrium temperature.
I'm also not losing it in the ductwork. The new contractor I have looking at it put his gages on the lineset and said everything looks fine.
If I take the temperature at the inlet and exit of the air handler, I get a delta T of only 10 degrees. I'm pretty sure this is where the problem is, but my HVAC guy has not been able to get out the last couple days to diagnose it further. Any thoughts? (and yes, I've changed the filter.)
Thanks.
Jon
R 30 for an area that reaches zero is below code in my area of the midwest. R 35 is usualy a minimum code in zone 5. R35 are minimum code requirements, key word is minimum, to keep you from going broke to pay your utility co.. You should be looking at R 60- 70-R 80+. I upped my attic to R 100- 110 and second floor temps went up 5f. Old standards need to be upgraded in this area. Also insulation settles and fiberglass looses efficiency as it get cold. Perhaps as much as 25% at Zero. Measure what you have in inches and calculate your true R and put in alot more. How cold does it go in your area.
Is the attic open unfinished
R- 100? That's absurd.
For a 1750 Ft2 home here is what your R-100 does for you
R-38 = 3407 BTU total R-48= 2590 BTU r-100= 1290 BTU
So, your very seriously wasted a great deal of money on your R-100.
Did they install the geo pipe into water wells? What antifreeze solution did they use?
There is a 3 ton unit
Do you mean the loop water line or an actual refrigerant line? If its a refrigerant line then you have a split unit? thats were the compressor is separate from the air handler? Is the air handler in the attic or conditioned space?
This is NOT an indication that everything is fine!!! All this tells me is the back up heat is working and your paying about four times the amount of electric than if your unit was running by itself.
Geo's will run all the time when its cold outside.
I've checked and sealed any
R-44 to 48 is the standard.
What else did he do? I need exact information here.
All this tells me is the back up heat isn't working and the geothermal unit is. But it doesn't tell me what the geothermal system is actually moving in BTU's.
I'm pretty sure this is where the
Yep, I think your HVAC guy needs to be fired, there are tests that will prove what is wrong with your system. One thing I notice is the upstairs units back up reistance heat or what ever type you have isn't installed, hooked up or isn't working or being called to work.
The downstairs unit temperatures tell me that the resistance heat is working but maybe not the Geo. The HVAC guy could have done all the necessary tests without puting his gauges on the refrigerant lines. As a matter of fact, if this is the only thing he did you got ripped off big time.
Geoman (and others),
Consider this a blanket reply to some of the posts already.
Geoman, comments below to yours. Thanks.
Geoman wrote:
solution did
The vertical wells are closed loop. They drilled through limestone, but did hit water in some regions. I believe the solution in the pipes is a methanol solution, don't know what concentration.
compressor is
Yes, it is a split unit. The refrigerant line runs crom the compressor to the air handler. The air handler is in the attic - unconditioned space. I also noticed they only used R-4 supply pipes in the attic, but the temperature drop from the unit exit to the room supplies is minimal.
full-time
My fault for not providing all the information. Up until last week when it dipped below zero, I have had the breaker for the electric backup on the first floor unit turned off. I haven't needed it. On a standard 10 degree day the unit runs about 1/2 time to sustain the set temp without the use of the backup. Only during the cold nights when the 2nd floor temp has been dropping to 65 has the first floor unit kicked the back-up on. I've been monitoring it and it has not been on much.
Again, just not what I'm seeing with the first floor unit. That's the primary thing that confuses my new contractor. He said he would have expected to see the first floor unit running full-time to try to supplement the 2nd floor, but it's not working that way. It still cycles on and off without calling the electric. The entire first floor is comfortable.
losing
I'm not sure, I was not home at the time.
geothermal unit
That is the one thing I am trying to rectify. The second floor air handler was installed without the heater because the original contractor (now out of business) indicated it wouldn't be needed. I need to add the breaker and run the additional line up to the attic in order to add the heater. That said, while some of this might be offset by the heater, I still think there is an issue. Even on a moderate day in the 30's, the unit runs non-stop and the exit air temperature is low.
upstairs
installed,
Again, this is the third contractor - original one out of business, second one just to charge the lineset for 2nd floor unit, and this one recommended by other builders and the ClimateMaster distributor. He is aware the 2nd floor unit does not have the electric backup and is ordering one for me. However, his other houses in the area with Geo are not having problems. My neighbor has the same ClimateMaster Split system and has not even turned on the breaker for the electric backup. They keep a slightly lower set temp, about 69.
I have a stick thermometer at home and will get the inlet and exit geo loop temps tonight. If you have any other thought on simple things I can check, I would appreciate it. What would help? Pressure reading from the gage on the primary unit? Loop temps? Is there a way I can get flow rate based on jumpers/dip switches and line diameters. I've found the ClimateMaster manual to be mostly useless for troubleshooting unless I get a fault code (which I'm not). The Trane air handler manual has no technical specs whatsoever, so I'm not sure what kind of delta T I should get across the air handler. Thanks.
Jon
Some follow up info:
Attic Air Handler is Trane Model TWE031E13FB1, marked as using Refrigerant 22.
The ground loop is split between the two ClimateMaster Units. Loop temp in is 30.8 deg, loop temp out is 26.7 deg. Current outside temp about 10 degrees.
The line out of the smaller compressor that runs to the attic measures about 151 deg when I place the stick thermometer inside the insulation and next to the copper (3/4 inch). In the attic I again placed the thermometer along side the line before it runs into the air handler. There I measured just under 140 deg. Not sure if it lost that much heat over the trip or if it's just because the measurement is in unconditioned attic.
Pressure gage on the 1st floor geo loop connection reads 49 psi.
Anything else I can measure or check myself, just let me know. Thanks again.
Jon
Jon, the HVAC guy must start from the beginning and have no short cuts.
Ask him if he knows how to mathematically calculate and determine CFM's Ask if he KNOWS how to determine the actual BTU's that the Geothermal is delivering into the home.
If he can't answer with a solid answer then call another dealer, he isn't familiar with the proper way to test and perform checks on Geothermal, especially Climate Master.
If he doesn't know what ARI ratings of the geothermal is and doesn't have them, tell him to leave, he doesn't know what he's doing.
Now, the unit not having a back up heater is bull. What if the unit fails? No wonder the original company went out of business.
I'm still don't think the HVAC guy still isn't the right one for the job or he would have done this when he first came on the lower unit. He should be able to tell you exactly what BTU's are being delivered into your lower unit. After you install the heaters he should be able to tell you the same thing about upstairs. Even without heaters he could perform tests and determine this value, especially if it was in AC mode.
Now, if he can do all this and knows what he's doing and everything tests out ok including the loop, then the next step is to do a heat loss/gain and see if its too small. Then if the heat loss is ok, the unit is sized right, the loop performance is good then get someone in with a blower door and see what those numbers are.
To be honest, there is no one in the world that can put a set of gauges on a system and say, 'everything looks good'. All the gauges do is give you pressures and tells you nothing about capacity, COP, EER, Seer and other information. Those who put a set of gauges on and determine that everything's ok is defined as a 'hack'.
In 15 years I have only two times put my gauges on a geothermal unit, it usually is never necessary. Everytime you put gauges on a system you introduce contaminants, and why put them on when they aren't going to tell you very much...
Keep us informed.
Rich
Rich,
Thank you for the comments. I will certainly ask him those questions when he returns my call. Unfortunately, the subcontractors in this area jump when the builders say jump and there is just too much new construction going on right now. I General Contracted the house on my own and did about half of the work. It actually came out better than some of the spec homes in the area, it's just the headaches of dealing with subs that don't make you a priority.
I've been trying to gather some of that information to do the calcs myself. I've got BS and MS degrees in engineering, so the heat transfer equation is no big deal. I don't have access (as far as I know) to Manual J, etc, but I did compute total wall area, knock off for windows, doors, figured for R-values, etc. - the basics. If I could find the info in the manual as to how to determine the flow rates, blower speeds, etc, I could do it. If you can point me in the right direction or are willing to walk me through it, I would appreciate it.
The interesting thing looking back is that I originally had 4 companies bid this house. I still have the original quotes and the range in unit sizes is : 4 Ton unit whole house, 2 1/2 ton first floor + 1 1/2 ton
2nd floor, 3 ton 1st + 2 ton 2nd (my system) and a 6 ton whole house unit at the high end. Yet all of them were in the range of 600 to 750 feet of ground loop, with 750 being what i have.Thanks again.
Jon
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