Missouri please help, 3 or 4 ton 5 or 7 series WF

Discussion in 'General Discussions' started by turbo v6 camaro, Jul 13, 2018.

  1. turbo v6 camaro

    turbo v6 camaro New Member


    I need some outside advice before we Drop 20K on this.

    basically our old mammoth system is 3.5 ton. its dying. Currently it is cooling "okay" but is not really dehumidifying, its running nearly constantly

    current loop out = 96 current loop in =84 (st louis area, its hot right now) (IR on the metal parts 6 inches from my pumps)

    3 companies, 1st only sells climatemaster.

    2 sell water furnace this price are within $1000 to 2000 for the CM

    2nd vendor
    one will not sell me a series 7, even the 3 ton, saying we don't have the loop for even a 3 ton unit. so they want to do 3 ton 5 series

    3rd (this vender sell both CM and WF)
    (this vendor does the well drilling for geo in this area)
    one is recommending the 7 series 4 ton,

    this thinking is our loops are 450feet and this makes with the current temps we are seeing the system
    (system was drilled in 1987 and 125ft per ton was used at that time vise the 150 now) 450/125=3.6 ton

    the 4 ton unit can handle full load and since it variable will not have to run at the full 4 tons, except on the extreme hot/cold days

    we can run on this for s year or 2 and if it keeps over running the loop we can dill new loops in a couple years at a cost of about $8K

    the thought is a 3 unit will be undersized and run in stage 2 for a 5 series or full bore for the 7 and not really be efficient

    house is 2500 sq feet, slab, single story

    thoughts ?
  2. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    The load has not really changed. The 7 series is more efficient, meaning that it will pull out a bit more heat from the ground. But it does not do pulsing either, having a constant draw on the loop. So worst case the loop will drop from 30F down to 29 or 28F, but work a whole lot more efficient.

    Vendor 2 is silly.
    7 series will find its sweet spot, no matter what. Plus give you the most comfort.
  3. arkie6

    arkie6 Member Forum Leader

    84F inlet temperature during the middle of summer is fine, but I wouldn't trust an IR temperature gun for exact measurements. This doesn't indicate an undersized loop. The 12F differential temperature across the unit seems high and may indicate your loop flowrate is too low. Are your loop pump(s) properly sized? Are your loop pump(s) working properly? Is there blockage in the lines or elsewhere? Other units such as Climatemaster target a 5F differential across the coil. The rule of thumb for closed loop systems is 3 GPM/ton of heating/cooling. Please describe your loop pump arrangement.
  4. nc73

    nc73 Member Forum Leader

    If you need to add more loop and have space you could just dig trenches instead of drill.
  5. turbo v6 camaro

    turbo v6 camaro New Member

    thank you for the input !
  6. turbo v6 camaro

    turbo v6 camaro New Member

    I know the IR is not perfetly accurate (when measured in the past iwas was about 5- 7 degress off from a probe that was in the line, that is why i made sure to mention is was an IR reading)

    as far as i know the system has been siting ther since 1987, I can only assume the pumps a properly sized, ther are 2 pump one on the return from the ground and one on return to the ground. I think they say like 3Amp max on them but i would have to double check

    we dont know the exact size of the loop, the prevouse owners, the wife said 450 (3x150 feet) and the husban said (3x315) or 945 feet total. so we really dont know and i have checked county records and they were not required to registat heat pump wells until the early 90;s

    we did have the system flushed in 2012 do to a leak in the wells, above ground nad easy to access thank goodness. they said the wells where fine and in good shape at that time.

    i cannot hear any cavitation near the pumps

    on saturday it was really hot, system was set 70 but temp inside was 73 the loop show 100 out and 92 in
  7. turbo v6 camaro

    turbo v6 camaro New Member

    i wish but we have like 6inches of soild and then hard bed rock around here, the only way to this would be to bring in a lot of fill
  8. arkie6

    arkie6 Member Forum Leader

    92F inlet temperature isn't great, but it isn't horrible in the middle of summer either. Also, the system may not have originally been designed to maintain 70F inside temperature at peak summer time temps. Most systems are designed around 75F inside temperature at peak outside design temp. If you are able to maintain 73F inside on a peak or higher design temperature day, then the system is likely functioning close to the way it was designed. A unit running nearly continuously under these conditions should be removing humidity from the air unless the coil temperature isn't cold enough to wring the moisture from the air or the condensate isn't draining properly. Have you observed your condensate drain pan to verify if condensate is forming in the pan and draining out properly? If the condensate pan drain line is plugged due to slime formation in the line (common problem), then the condensate may be building up and getting pulled back into the air stream effectively negating the dehumidifying effect of the cooling coil. This is something I recommend be checked. You may have to remove a side cover from the unit near the condensate drain line to inspect this.

    Have you done a measurement of your supply air temperature and your return air temperature as close as possible to the unit on a high temperature day? If so, what temperatures did you get?

    Also, where is your ductwork located? In the attic? Is it rigid ductwork or flex? Have you inspected it recently to verify it is in good shape with no tears or missing insulation? Does it have adequate insulation? Is the insulation foil covered in dust which negates the IR heat blocking effect of the shiny insulation covering?

    What type and how much attic insulation do you have? Is it blown in cellulose or fiberglass batts? If fiberglass batts, blowing 6" of loose fill cellulose on top would help reduce attic air infiltration by filling in gaps between the batts and significantly improve the IR heat blocking of the fiberglass (IR heat penetrates deeply into fiberglass batts, but not more than an inch or two into cellulose).

    What about your windows? Any west facing windows that aren't shaded outside? Are they low E coated windows with low solar heat gain?

    Your money might be better spent improving your ductwork, attic insulation, and windows rather than replacing your HVAC unit.

    It might be worthwhile to check with your local electric utility and see about getting an energy audit done. It is usually free and can often diagnose weaknesses in your building envelope that can have a significant return on a minimal investment compared to the cost of replacing a functioning HVAC system.
  9. turbo v6 camaro

    turbo v6 camaro New Member

    the system stopped draining out the hose, it is not cloged, its dumping water all over the floor now, the system is running all day but the humidity is 60-65%

    i have, i dont remember the exact temp the IAQ has temp probes but i can not see them without entering a the test mode. it is usually 2-10 degree drop from return to supply

    attic, main line is the 8 inch by 18? inch rectangle stuff (same for return) the line run off of those in thos flex able insulated tubes (they are 10 to 12 inches) a assume that mean 6inch under the insulation

    umm you could say it dusty lol

    we had the shiny stuff installed on the roof rafters 3 years ago, also had the blow in type brought to R44 i think it was its like almost 2 feet deep now

    LOL they are dual pain, lot of south windows, wood frames. custom, (house bluit in 1987) I think it would be cheaper to rebiuld the house than replace the windows, I did have a guy with IR come out and check, wall insulation is fine (bat not blown)
    I have thought about getting some of the heat blocking tint for the windows though, it really helped in my car !!

    also the IR showed we did have one window that lost the seal, it is "on the list"

    I also used the IR guy and sealed and replace seals that where leaking, the front door was really bad got it fixed up now.

    already spent about $12k doing this the unit was fine until this year

    see above

    thank you again for the question hoping im answering them well, I can get better numbers, but kiddos are asleep and acsessing hte unit rught now is like walking mine fields lol
    Last edited: Jul 17, 2018
  10. arkie6

    arkie6 Member Forum Leader

    If the the unit is not dumping water out of the condensate drain line but is dumping water all over the floor, then either the drain line is stopped up or the condensate drain pan has a hole in it or the unit isn't mounted level. How did you verify the condensate drain line is not clogged? The slime plug I referred to earlier typically occurs right where the condensate line connects to the condensate pan. If you just checked for clogs from the vented P trap to the downstream end of the line, that won't find a slime plug at the condensate pan drain hole. You will likely have to remove a panel or cover on the unit to access this drain hole in the condensate pan. If water is standing more than ~1/4" or so in the pan, then the most likely culprit is a slime plug in the drain hole. You can dislodge the plug with something flexible like a nylon zip tie poked down the hole. If that is found to be the problem, you can pour some distilled white vinegar down the line to kill the fungus that makes the slime.

    Most condensate pans in the last 20 years or so are made of plastic, so it is not common that they leak (no corrosion issues) unless it is at the joint where the condensate line attaches to the pan.

    As far as temperature delta T across the coil, you should be seeing around 20F drop. If your return air temp is 73F, then your discharge temp should be 53F give or take a degree or two.
  11. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    I cooling mode, you actually heat the loop less with a variable speed equipment, due to higher efficiency.

    Cooling delta T is actually around 10F on the water side if your loop is around 84F.

    If the unit is operating well, but you missing a bit capacity, why don't you put in a 4 ton?

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