Is there any excuse for a heatpump not keeping up other than improper sizing?

Discussion in 'HVAC Heating & Cooling' started by Tom Chambers, Jul 30, 2018.

  1. Tom Chambers

    Tom Chambers New Member

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    I am pretty sure what he meant is that he knew i was wanting a dual stage and i have not found any 1/2 ton in the geo 2 stage category... Especially in my chosen model Trane or Bosch. So yes there are plenty of 1/2 stage in the single stage version but kinda makes sense as when you get a 2 ton the dual stage makes it simulate a 1.5 thru a 2.5 depending on how its running... so have you actually seen a model in 2 stage half size. If so please id it by model number so i can have a chat with my contractor.. and why he was so adamant that he could not provide me a 1/2 stage..
    I searched again this am and found nothing.. however i may not be that great a searcher.. if yours is a single stage and a half that makes sense.
    Would be a tough project to switch air handlers.. as the lower is a bosch and 3 ton UN-SPLIT.. while the up is a 2 ton TRANE split.. wish it wasn't split as that alone would make it more efficient.. and in most cases the tech does not have to get in and mess up the freon levels.. since normally they do not need to even check it..

    But I have been wanting to force the up to a 3 ton and keep the 3 down as its doing great... but scared if I push too hard might get a rest period on and off as i want and find that it no longer removes humidity due to over size.. so trying to force a manual j to confirm if I really need to go larger... 800 should be fine for 2ton but for some reason its just not hacking it..
     
  2. Stuff

    Stuff Well-Known Member

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    So far still speculation as no manual J done or other calcs, blower door test, etc.

    Removing 10 gallons/80 pints of condensate a day is a lot. What does the humidity level measure? Is a humidifier stuck on? Humid air rises so could be from elsewhere in the house.
     
  3. Stuff

    Stuff Well-Known Member

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    Also keep in mind that going to a larger system will most likely not decrease your electricity usage. A 2 ton running 24 hours would be similar to a 3 ton running 16 hours.
     
  4. Tom Chambers

    Tom Chambers New Member

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    Humidifier stuck on????? What do i have a humidifier.. never heard of that? What can i check to see?

    Not sure what the humidity is.. but must be high as you said.. I would ask my contractor to bring a humidity monitor or one of his 3rd party GEO expeerts but like NO manual J or NO manual D... not sure they have any such tool as that.. may have to invest in one of those as I do need to get on Ebay and buy a PT water pressure gage so i can tell my contractor what the water flow is.. my guess its about 8-9 gpm when it should be 6.5 since all throttling valves are wide open.. meaning both up and down systems are at the becon and call of the max gpm from the pump as no adjustment (throttling can be had from wide open valves..) but i doubt the water flow is the problem.. but its totally set wrong and should be set close to mfg specs to make sure i don't void the warranty.

    Thanks for the suggestions will try to do what i can but not getting any cooperation on a Manual J.. hope to keep aggravating Trane until someone comes out.. but not so far..
     
  5. Reach4

    Reach4 Well-Known Member

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    A hygrometer (humidity meter) can be pretty cheap. You don't need a laboratory grade unit. The electronic units usually are combined with a digital thermometer.
     
    Last edited: Aug 7, 2018
  6. WorthFlorida

    WorthFlorida The wife is still training me.

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    http://hvac-talk.com/vbb/showthread.php?995391-Manual-J-AC-sizing-for-multi-story-house

    Here is an old post (2009) from another forum. Again the mystery on how to handle a two story two unit home. This homeowner had a 5 ton second floor, 4 ton first floor. For the new efficient units it would be way over kill to stay with these sizes. The original reason I think that the original contractor (Houston, TX) probably learned to eliminate nuisance service calls that the second floor is never cool enough, he oversized it.

    Right now I'm at my brothers 2 story 2 AC unit home on Long Island, NY and the weather is at its worse. 90 degrees plus and high humidity. Both units are 3.5 ton each, twenty years old at SEER 10. The home is around 3500 sq ft. The second floor remains relatively comfortable and just slightly warmer than the first floor, and yes, that second floor runs quite a lot during the day with the thermostat set to 78 degrees. A big help is the second floor air handler is in the attic so the return is on the ceiling. There is enough capacity that the second floor temp can be brought down lower.
     
  7. Dana

    Dana In the trades

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    You'd have to have the crummiest house in Virginia for the cooling load of an 800' second floor to be 2 tons. An insulated 800' upper floor with glass in the windows (and windows closed) would normally have have a true cooling load of a ton or less a the 1% design condition (unless 4 bedrooms full of teenagers with high performance game computers running 24/7).

    If the air handler and ducts are in the attic, above the insulation it could add as much as a ton to the load (which is a good reason to never put the air handler and ducts in the attic.)

    Most problems like this are related to poor duct design/implementation rather than equipment sizing. The large amounts of reported condensation makes me believe the ducts are either leaking or unbalanced (or both), driving high levels of outdoor air infiltration whenever the air handler is running. An unbalanced duct system creates room to room pressure difference using "the great outdoors" as part of the return path. Ducts/air handlers in a vented attic above the insulation that leak air can be even worse infiltration drivers.

    If this system has a ventilation-air intake, that may be another contributor to the huge latent load.

    Taking a bad duct/house design and simply throwing more heat pump at it may or may not solve the comfort problem, but fixing the fundamentals would in most cases be cheaper. Using manometer to verify and fully commission the ducts, and to check for high room to room pressure differentials (and fixing any return path or supply duct impedance issues) is likely to be both cheaper and better.

    Regarding sizing, this graphic was compiled by an HVAC consulting company (Energy Vanguard, in Decatur GA) plotting house size against the square feet per ton ratio on dozens of their Manual-Js done for clients:

    [​IMG]

    Note that even the worst performing house (of any size) has a square foot to load ratio of 600' per ton. Assuming your 800' upper floor is like the worst of the 800-1200' houses in the sample set you would be looking at a 1-1.5 ton load.

    With reasonably balanced and tight duct systems the parasitic load of ducts & air handler in the attic would usually be about a half-ton, sometimes less, which added to the load of the worst 800' upper floor space in Virginia about a 2 tons of load.
     
  8. Tom Chambers

    Tom Chambers New Member

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    Are you saying that sized properly and basically a tight system it should not run 24x7 as i have been having a problem getting many folks to agree with me. For most folks it seems feel it is ok to run 24x7 as long as it can hold the temp in reason... Course 24x7 means no electric savings and that is what all the geo claim... Think i have embarrased Trane enough to send out a rep since I made formal complaint against the TRane since my contractor has given up.. actually i am just using Trane to get him off his ass and find out what is wrong and fix it... or at least force a rebate so i can get a real geo person as they know less about Geo than i do...and even worse is the two 3rd party Geo experts they hired to bail them out all put together might know half what i know... and i don't know that much. LOL.. but at least i do know how to measure the water flow using the differential of water pressusre at the PT1 and PT2.

    Is there anything i can look at to see if it appears to be balanced... its all mastic sealed and i have moved toilet paper over all joints to see if i could detect a leak.. none so far. it is all new ducts and airhandler just over the attic insulation. Emailed the contract to Trane yesterday hope to hear from them tomorrow..

    Someone told me to pressurize the ducts with oxygen and look for leaks with an oil squirt can.. but i decided not to do that one. Just kidding.
     
  9. Dana

    Dana In the trades

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    A right sized system will run longer cycles than an oversized system, but uses less power since it also runs FEWER cycles. The compressor spin-up is grossly less efficient than the steady-state system, and it takes several minutes for most heat pumps to reach their steady-state efficiency. Even at the same steady-state efficiency a right-sized system that runs a 90-100% duty cycle during the the peak load hours ends up burning fewer kwh than a 2x oversized system running 45-50% duty cycle during the peak load hours, since the oversized system suffers the hit of having roughly twice as many spin-up ramps, and at steady state it's running proportionally more power. Bigger compressors take more energy to spin up than smaller compressors, so the efficiency hit is bigger than the simple-math model might make it seem, but that's the gist of it.

    Duct leaks are detected by pressurizing the system to 25 pascals with a calibrated duct blaster and measuring the losses, not by peeling the duct sealing apart and eyeballing it or waving TP over the seams. (In California under Title 24 regulations this is a required step for commissioning duct systems- there is a maximum allowed leakage- fail the test and the contractor has to find & fix it before the system can be sold.)

    Duct balance is best measured by measuring the room to room pressure differences with the air handler running at maximum speed, with all combinations of doors open/closed. To get Energy Star certification a home with ducted HVAC can have room to room pressure differences no greater than 3 pascals (=0.012" water column). The resolution of most cheap hand-held dual port manometers used for normal duct & air handler diagnostics is typically in 0.01" increments, so it's not really the best instrument for measuring the room to room pressure differences, but it can find the worst-offenders pretty easily. A measured pressure delta of 0.03" between rooms is definitely going to be an infiltration driver.
     
  10. Stuff

    Stuff Well-Known Member

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  11. Tom Chambers

    Tom Chambers New Member

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    Thanks.. sounds very technical but certainly sounds reasonable but since my system was never designed there is no way to know at what point it would need to run 24x7... since no manual j nor manual d was ever done.. so no design no idea if it designed itself for 77 or not.. LOL.

    Finally after pulling a lot of teeth Trane has agreed to give it a look to see if its me or the contractor or their equipment...

    Well looks like we are moving closer to an answer... and I can deal with it if Trane says that I am just a whiner and their system just cannot be expect to do what I ask it to do such as "Hold the heat at 75 when the OAT goes above 80... but my guess is they will kick ass and take names and tell the contractor what he needs to do to continue installing their products in the future..... especailly when he asks for such things as:
    1. Commissioning data...
    2. Manual J
    3. Manual D
    4. and other simple shit like what is the water flow set at rigth now?
    and they cannot answer a single question even when talking to the other two 3rd party GEO experts that my contractor paid for.
    5. should really be funny... will keep you posted..

    Email from Trane today.....
    Mr. Tommy,
    Thank you for providing us with this information and we again apologize for any inconvenience this may have caused. Your issue and documentation has been sent to the Escalation Specialist for review. They will contact you once they have a resolution to this issue.
    Thank you for choosing Trane, American Standard and Ameristar. We appreciate your business.
    Thank you ,
    Franki K.
    Trane, American Standard, & Ameristar Consumer Relations
     
  12. Dana

    Dana In the trades

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    It's a sad fact that a large number of HVAC contractors are pretty clueless about the equipment they're installing, have never done a Manual-J or Manual-D, yet are still in business. It's one thing to get it rong when installing a cheap gas furnace, but quite another when dealing with heat pumps, even more so with ground source heat pumps, which are always semi-custom systems, with more factors to calculate & manage.

    There are few things as expensive as a cheap geo contractor who can't properly use Manuals J & D or properly spec a pump. A hacked-together geo system can run substantially lower efficiency than a reasonably sized (for the load) air source heat pump, after all pumping and air handler power is factored in.
     
  13. Tom Chambers

    Tom Chambers New Member

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    and what makes it so bad is that most have straight 5 on review.. Mine did.. means nothing.. First the reveiw is done by a homeowner who has no idea if they did a good job or not or even if they changed the right part. but if they do shotgun it and fix it.. then the poor homeowner says wonderful he saved me from all day with no ac.. Never mind the first 3 parts we not bad.. bottom line is he got it done same day... In my case he told me to get the well driller to run a new return line.. to the wells at a cost of nearly 2 grand.. I said bullshit 30 psi in my return line has nothing to do with the problem and is not unusual. So he talked my original contractor into upsizing the return lines to the well to 1 and 1/4.. GEESH what an idiot.. and now following that big expense the return (backpressure) to the well is 35 instead of 30... but oh well i get new lines..and they were free so i am ok with that... but hate to see my contractor get ripped off.. would rather he spend his money on the real problem... now maybe Trane can convince him to do that. But this GEO Expert(so called) has a great record... yes he does a record of shotgun.. and sure enough once the new line to the well were drilled he would come in to turn it back on and notice the 4 flashes from the fault panel... and remove the double trap in the condensate line and start it up and say... "SEE I told you drilling new well return lines would fix it... hear it purr.... yeah you idiot it would purr just fine when you remove the double trap in the condensate line whether or not i drilled any return lines.. WHICH I DID NOT and WOULD NOT unless someone besides me is going to pay for it...
     
  14. hj

    hj Moderator & Master Plumber Staff Member

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    RE' that reply that the HOMEOWNER had to request a heat analysis. The installer is the EXPERT and as such MUST override the customer and provide the PROPER Sized equipment, or refuse the job.
     
  15. Dana

    Dana In the trades

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    If only the people installing this stuff actually WERE the experts! Some installers clearly are experts, but unfortunately the industry track record isn't all that great- I'd be hard pressed to say the installers as a whole are batting 500 (or even 200.)

    Of course "problem systems" are far more likely to end up being discussed on forums like this than those designed & installed by actual experts, so a web-forum poll isn't the best sampling method. But it's really hard for homeowners to separate the wheat from the chaff.
     
  16. Tom Chambers

    Tom Chambers New Member

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    <quote>RE' that reply that the HOMEOWNER had to request a heat analysis. The installer is the EXPERT and as such MUST override the customer and provide the PROPER Sized equipment, or refuse the job.</quote>

    Surely you jest.. shouldn't we say the Installer should be the expert and sometimes they are and sometimes they are anything but.. and my odds have been pretty bad.. three of three duds... here is my 3 duds...
    1. original contractor... so bad he realized he had no idea what he was doing... and he has been a Trane Dealer for 30 years... just not a GEO Trane dealer.. there is a big difference it appears...

    2. First 3rd party geo expert: knew maybe 1% more than the original contractor who gave up immediately after install. Have no idea what his expeience is.. but he owns the company.

    3. 2nd 3rd party geo expert: he did approach a 1% knowledge factor.. but was a close call in many ways he was worse than the first.. at least the first one did not carry a shotgun for troubleshooting.. This dud was so good the GEO distributor recommended him to my contractor as he was known to have 20 solid years in installing and maintaining GEO and had purchased and installed many from this GEO distributor.... The only thing that i will say he was good at was plumbing.. as I observed him weld a 3/4 copper water pipe so nice that it would make your eyes water and i am sure Trane will love him even more when they see that instead of replacing their failed internal leaking water SOV with an approved replacement Trane part he replaced it with a rainbird and voided my warranty.. they might even give him an award.... heck Trane may just walk away and say sorry.. cannot help you with a void warranty.. ask your contractor to buy you a brand spanking new system that has warranty remaining.

    Let me see if i mis-understood your comment.. I should not be requesting a Manual J or Manual D.. as required in many states before you can install and highly recommended by all hvac manufacturers. and let him do what a normal PROFESSIONAL does.. Seat of the pants - educated guess... is that what you just said or did i misinterpret it..
    These so called professionals are gonna be really embarrased as i am pretty sure the Trane rep will want to see the Commissioning Data... good luck with that as not one of the 3 companies have any idea how to check the mfg GPM for water.. or much else.. and none have done it.. at least one the first did the old 5 gallon bucket test... which is better than nothing.. but totally meaningless.. as this is one time the backpressure to the return well really matters.... if you have 40 psi in and 30 psi backpressure the flow will be drastically more into a 5 gallon bucket then it will when in the closed loop to the well.. a bullshit guess would be maybe twice as much so even though it frequenlty used its meaning less... Some will argue that its a ballpark figure... BULLSHIT it aint even close and i can prove it to anyone who really believes that crap...

    Normally as you say its true the home owner is at the mercy of the so called Professional and what he says goes.. since who is the homeowner to tell him anything.. he went to school on HVAC for 12 weeks and has 23 years on the job experience.. like my so called Geo Expert...with the shotgun.. blazing as he trouble shoots...and the homeowner has never been to school on hvac.
     
    Last edited: Aug 10, 2018
  17. hj

    hj Moderator & Master Plumber Staff Member

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    The UCC states that the installer is responsible for supplying the PROPER item and if it is incorrect the customer CAN request a specific performance and the courts have enforced it. It is one of the responsibilities of being an "expert".
     
  18. Tom Chambers

    Tom Chambers New Member

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    Wow! More new developments... One of my requests weeks ago to the 2nd 3rd party GEO expert was to make sure my thermostat was on the up and up.. meaning when it says its 75 is it really 75 in the room. He assured me that he would bring in some equipment to measure the room temp way more accurate than the lower quality thermostats that you normally get... well my mistake I forgot to ask him how my thermostat checked out.. so never got back to me... now wondering if it ever got checked... so as I try new ideas that you guys suggest, i had my own brain fart.. as it does seem cooler than 80 degrees upstairs when it says its 80... So i unplugged my honeywell thermostat downstairs meaning when you unplug the front part of the Honeywell it brings away the entire thermostat with batteries intact and the thermometer still working but leaves all the wiring to the wall.. I taped this half above the other identical honeywell in the upstairs... after an hour or so of stabilization I noted the temps.... My downstairs unit taped to the wall above the other controller reads 70 degrees... the upstairs unit at exact same location reads 73 degrees... WOW! A full 3 degrees difference... so I quickly calculated that if i wanted the temp to be 75 degrees i could set it at 78 and that should bring in 75.. and sure enough it did.. and now i no longer run 24x7, more like 20x7 so it helped a lot as i was demanding 72 previously unknowingly... so of course its very difficult to keep the temp at 72 with outside at 85 and 90... so that is crazy... when the Trane many gets here its going to blow his mind that with all the problems i have been reporting with temps.. NO ONE has ever verified that the thermostat was not broken.... Both the honeywell are only 1 year old so they should be able to replace them with warranty... but i looked at my contract and it says i have Trane Tcont602 which i do not have... interesting to say the least be nothing from this team surprises me..

    Even with this development its better now... but to me running 20x7 cannot be size correctly.....or the system is just not right yet... well we do know that the water flow is incorrect but that will only make a tiny difference.. so not too concerned about that..

    The reason i have a honeywell vice a Trane thermostat is another story... that would bring tears to your eyes... so won't go into that.. in this drama i have only let you guys in on less than 1% of the screwups that have been done to me.... HECK we have not even gone into the major code violations electrically that will get my insurance cancelled if they knew.. but some are low priority that i will go after once I get cool... LOL.
     
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