Louisiana Humidity! HELP

Discussion in 'Maintenance and Troubleshooting' started by bjl, Mar 17, 2016.

  1. bjl

    bjl Member

    It's been awhile since I've posted, and would like to start off, these systems in South louisiana definitely is not for the faint of heart diy'er. I put in 8 horizontal runs of 670' apiece. Once down to 11' placed a 1' layer of river sand, then my slinky, then another foot of sand then my supply to the field, then another foot of sand. While back filling with the nastiest clay anyone can imagine, I would spread sand through the clumps as to create fissures where the water table can run more freely. The water table is 5' to 6' down normally. And was told in droughts it could drop to around 8', which is why I was shooting for a 10' depth.

    The house. It's 3800 sq ft, mostly 10' ceilings with a Lil at 11' and at 12'. The house was designed with efficiency in mind. Insulated
    low-e windows everywhere. 2x6 exterior walls with wet blown cellulose. House wrap is tyvek low-e radiant barrier then a 1/2"
    Air gap then double Bubble wrap for the extra insulation and radiant barrier. The air gap is not sealed so it can vent. Roof sheathing is 5/8" Osb with radiant barrier. As of now 5" - 6" of blown cellulose in attic. When work is all done I'll double it. Expanding foam or silicone all cracks. Tight house, while still allowing it to breath, persay.

    The system. I have two miami heat pumps. A 3.5 ton 2 stage and a 2.5 ton single stage. Now for my screw up. The manual j called for 5 tons and when I went to order them the sales person with the company talked me into stepping both units up .5 ton. I even called a local a/c company and was going to get them to do a 2nd man. J before actually purchasing. He told me the same thing after me telling him everything posted above with the house. So I did. I've since learned to err on the low side, not the high. I think it would be spot on with a 2 and a 3 ton 2 stage units. The house holds the temp s very well, so far. We haven't hit those really hot 100* days yet.

    The units been operating for about 5 - 6 weeks now. I've gotten the humidity down to 58% once with both units set to 60* and working their tail off. The units do have a "enhanced dehumidifying setting" that is definitely not set up properly. I've been n touch with manufacturer to help me through it. I know it's suppose to slow the blower down 30%. While troubleshooting, I did a hot test while in dh mode. Disconnecting the t/s hot from the dh wire, it sounds like the compressor is slightly bogging down and nothing with the fan. I do not have an air velocity testor, might get one though, so I taped loose paper at a register opening. With the change from stage 1 to dehumidifying it shows no change in movement.

    The tstats.
    Venstar t7900. These things are remarkable. Worth the extra $ to get the humidistat included. Humidity inside will drop to about 65% if I'm lucky. humidity outside is n the 80s and 90s. Btw, it's freezing inside to hold that humidity.

    A few other things I think needed is lwt - 89* ewt - 79*. When I first started the system it held at around 69* ewt. I purged the field a couple times within the 1st week. In week 2 I noticed the
    ewt - 72* or so. And it's held at that. I was surprised just now to see it at 79*. All 8 circuits are holding the same ewt. The lwt has held the same for the hole time. I check air temp going in a couple different times to air coming out and it's ranged from 14* difference To a 19* difference. I checked the condensate trap to make sure water is in it and it's not sucking humid air in. They are full but the amount of water in the trap seems to only b a couple ounces at most. The drip pans do not drain completly. The drain is on the side 1/4" up. At all times there is water in the drop pans. Found this out this morning. I checked for air infiltration and exfiltration, all good. Bought a thermal imager for my phone, cool toy, to check attic space. I checked the run time on the smaller unit and some times it short cycles, like 3 min, but it's something to do with this d/h mode. It drops 1* turns on brings up 1* then turns off. With the d/h mode off it ran for over 30 min and brought temp down 4* while the humidity came down 1%.

    The questions.
    When I put the t/s on say 60*, as the temp in the house drops, is it harder for a coil to remove humidity though the compressor is constantly running?

    Can water holding in drip pan keep the unit from dehumidifying?

    Can the unit pull humid air in through the condensate trap with a couple ounces of water in it? Is this enough volume to cause an issue?

    Should I be concerned with this rising ewt?

    Is the 3.5 ton 2 stage ok though it may b slightly oversized?

    I possibly have a chance to switch out the 2.5 ton single stage to a 2 ton 2 stage unit with little cost to me. Should I? The duct work is sized to a .06 static for the 2.5 ton. Will this make a difference? The duct did sweat a little but the units have been running almost non stop.

    If anyone is familiar with these humidistat controled dehumidifying modes, a Lil insight please. I know every manufacturer is probably different, but I don't know whether to set it to n/o or n/c. And why does it sound like the compressor is bogging instead of the fan. I am waiting for the manufacturer to get back with me also.

    I can't think of anything else at the moment, so I just read back through everything and it seems long. Soooooo, I do want to apologize if this is long. I think I'm venting while typing. This has been a daily battle so I will be checking the thread daily. Got floors cooming and want to get humidity down before putting them in.

    P.S. want to thank doc, Mark, and I believe it was earthboy for getting me this far.
  2. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Have you tried slowing down the air flow? De-humidification is about run time.

  3. geoxne

    geoxne Active Member Forum Leader

    Make sure the fan is off with no extended run time after compressor run. I had one customer that had his fan set to ON instead of AUTO. Once set correctly the RH in his house was reduced by 10%. Continuous fan will just reabsorb the moisture on the coil into the air.

    Try to discourage 2nd stage operation with thermostat settings.
  4. mrrxtech

    mrrxtech Member

    Being a DIYerselfer myself, I believe you have plenty of loop for your units, but your units aren't getting cold enough to condense the humidity in your house.
    The loop temperatures are higher than I have ever seen with my 4 ton unit cooling 2300 sq ft with 2000 ft of 1.5 ID pipe in one continuous loop at 5 feet.

    You might want to use the Checklist in this section to provide the unit performance information so these folks can get a sense of how your units are working. I'll bet my money on low water flow in your loops.

    I have a tygon hose to a floor drain for the condensate drain line, and can see a constant flow of water from the unit during cooling season. Are you seeing condensate flow or just water standing in the pans? If the Evaporator is getting cold Freon, the condensate will have to drop out. This is what you don't have.

    You have a whale of a ground loop by the way.
  5. bjl

    bjl Member

    I've been trying to get this dehumidifying mode set right but it's not working out. Hopefully the.manufacturer has more information on it because there is nothing on their website. I did double check the fan before and it is on auto. Going to tach the blower probably next week. Just got called In to work for the next Few days or so. With the oilfield like it is better get it wile I can.
    The ewt has me puzzled. I shot the tubing with a Infrared Thermometer so I know where the temp is at, but the.pipes feel ice cold. The lwt feels very warm. Grabbing them at the.same time they do not feel like a 10* difference. What is your ewt tech? I believe it was.doc Jensen that gave me some figures on the length of the loop field. I upsized it a bit to keep the pressure down and the.clay had me concerned. The original plans called .for vertical wells. They wanted to much money and I decided to do it myself. I know with one pump running the Reynolds number would be low but the.extra length of.pipe would make up for it.
  6. mrrxtech

    mrrxtech Member

    It sounds as if your units are running long enough to dehumidify. My unit has a constant speed fan (by my choice) with no dehumidification features except the cold evaporator.
    The big concern about oversizing a unit is during the cooling mode if the unit doesn't run long enough to dehumidify.
    I believe the extra features you have are to allow dehumidification first, then allow a short run time to cool the house which would save energy.

    With your units running all of the time the humidity should be low in the house.

    A 4 ton Trane assuming 55 degree loop temperature shows a 9 to 11 degree temperature rise across the unit. I remember seeing 10 to 12 degrees across my water coil. I have 2) 3 speed Grundfos pumps, in series, one pushing water into the unit and one taking a suction on the return side pushing the water back out to the loop, which I can run on low speed in the summer with no adverse effects on the cooling capability of the unit.

    In slow speed the entering water temperature from my memory has never been in the 80s and is more like low 70s. My unit has no problem cooling and dehumidifying the house, which is not "air tight" since I didn't use foam insulation in the walls. The Dow Safe Touch insulation I used allows some air to come in at the top of the walls due to sagging, since it was "friction fit", and wasn't designed with a 1/2 inch overlap to staple the insulation onto the studs. Dow stopped making Safe Touch, probably due to customer feed back.

    If you can read the pressure across your unit water coil, you can figure the flow rate from tables in your unit manuals. That information along with the water temperatures, and air temperatures across your unit should be enough to determine where your problem is. With 2 units, I'm betting the problem is with loop flow since it would be common to the units and account for the poor dehumidification.

    You might be adding another pump to your loop or doing some more air removal, after arriving at that conclusion using the operating data you collect.
  7. bjl

    bjl Member

    My circ sysrem is 2 grundfos ups 15 42f, 1 for each unit. All my pipeing is 1" He pex in the attic, 2" hdpe bringing it outside and then to 8 - 3/4" runs and back up to 2" manifold. The smallest line is 9' of 3/4" inside the unit Looks like this battle will have to wait a good week for me to get back on it.
  8. mrrxtech

    mrrxtech Member

    I had the same problem using 2) UPS15-58 circulator pumps. They are now in a box waiting for a project where I need a circulator that can handle light duty.

    The pumps that worked are 3 speed UPS26-99FC Super Brute Grundfos pumps that fit in the same space between the two flanges in my home made flow centers. The model I picked has a built in check valve and Cast Iron body.
    You can spend some time calculating head loss and pick out the exact pumps you need, or use these with 3 speeds to match what your system needs for winter or summer.

    If you used 220 vac to power your pumps, use model 52722513 these will be direct replacements between your flanges.

    If you used 120 vac to power your pumps, use model 52722512:

    Take a look at this on Amazon, you need to grab these now! It's a give away! I thought it was a mistake. Makes me want to buy a few more for back up.

    Last edited: Mar 19, 2016
  9. mrrxtech

    mrrxtech Member

    I'm assuming you used 120 vac so the Amazon deal won't work for you unless you are using 120 vac.

    Below is my spare flow center that was to be used on a closed loop system, but it was changed to an open loop system at the last minute. These are the Super Brute Grundfos pumps I recommended above.

  10. mrrxtech

    mrrxtech Member

    I'm assuming you used 120 vac so the Amazon deal won't work for you unless you are using 120 vac power source or want to switch over to it for the initial cost savings on Amazon.

    Here is the extra flow center that I built for another project, but we went with an open loop water supply, so now I have a back up flow center for my Unit.

  11. geoxne

    geoxne Active Member Forum Leader

    I took a look at 5 different wiring diagrams from Miami Heat Pump here-
    The only one that made sense to me was this one-

    I am not sure which wiring diagram is correct for your equipment but if we walk through the control logic you may be able to trace and work it out. Also please note a 2stage compressor and X13 ECM fan motor is required to make Enhanced Drying work.

    Basically it appears during "Enhanced Drying" (or DH) mode a relay breaks a Y2 compressor and stage 2 fan calls. This will allow for longer run times and better dehumidification at reduced compressor and fan speed. If controlled by a humidistat (rather than a dehumidistat) you will have to apply "reverse logic". In other words during a EDR (DHR) demand the relay is unpowered. When the EDR(DHR) demand is satisfied, the relay will be powered and allow stage 2 operation

    Now toss in your smart thermostat that can be configured as a humidistat or dehumidistat and both either normally open or normally closed, and it is easy to confuse the logic.

    I would start by disconnecting the connection to EDR(DHR) and see what happens. You can compare stage1 and stage2 compressor and fan speeds with a clampon ammeter. If I am right than you can setup your thermostat "AUX output usage" to "Dehum" and "AUX output polarity" to "NC" (normally closed).

    If I am wrong, you will have to refigure the control logic and trace wires and relays, maybe with some help with Miami Heat Pump.
  12. mrrxtech

    mrrxtech Member

    Those Super Brute 120vac pumps are now priced well above the $62 that was showing on Saturday. I selected 2 pumps for purchase and the price was $124 but then realized they were 120vac pumps which I don't use. They must have mispriced the pumps.
    My 4 ton Trane unit tripped within a few minutes when I was using the undersized pumps. Your units must be close to the trip setpoint but not tripping due to having low water flow.
  13. bjl

    bjl Member

    So I finally get back to work on my problem and find I have a thermostat that lost its firmware. Been trying to troubleshoot it but looks like I'm sending it back for warranty.
    I finally got tech support from miami heat pump and we went step by step through several wire configurations but really did not find anything. Yes geo, that is the diagram ive been studying. I did have the t/s set to dehumidify and n/c. At one point I noticed the compressor sounds like it is bogging down when I disconnect the edr wire, so I changed it to n/o. The fan speed does not change. Fan rpms were 750 - 800 normal and 700 - 750 with the edr wire jumped to the fan wire. From what MHP is saying the units are stuck In High. I checked my other unit and it's similar. 2.5 ton single stage. Fan rpms are 585 - 595 normal and 565 - 575 in dh mode. Not a big difference.

    I'm going to do a good run time over my next work hitch and see how long the units actual runtimes are. And my pump supplier will laugh his tail off if I have to get more pumps. This is the 2nd set I had to get. I know I ordered variable speed, and I didn't know I got single speed until almost a year later after they r installed a ready to be wired. Luckily, they took them back and replaced them with these. The only advantage is that I took the ss volutes off the 1st ones and replaced the cast iron ones. I did mic the openings for the impeller and did a test run and everything was good. I did also remember that I never did finish burying my trench to the house, my excavator broke down. About 20' of the hdpe (8 runs of 3/4") is exposed to sunlight. And if water is in the trench it's exposed. Talk about a big DUH. Would explain an elevated ewt. I did turn my pumps on high though. I had a flow meter but it wouldn't work right. I'm going to do a flow test to see what the pumps are actually pumping before buying some more. The pumps are 220v
  14. bjl

    bjl Member

    Mrrx, I tried opening your pic, but it told me there was a error.
  15. mrrxtech

    mrrxtech Member

    If you can measure loop water pressure at the inlet and outlet of your unit, the manual has a conversion from differential pressure/total pressure drop to flow. You can compare that to the tables for your unit to see what area it's operating in.
    Given that both units are are "Stuck In High", supports the low flow theory, since the ground loop is common to both units. The head loss of having 8) 600 plus feet of ground loop has to be more than my 2000ft once through 1.5 inch ID loop that my first circulator pumps wouldn't move water through fast enough to keep the unit from tripping on High Pressure in the cooling mode.

    If your geothermal units were working correctly, and ran for an hour, let alone all day, your house would be dehumidified.
    The picture was of my spare home made pump center which I copied from a post on this website. If you can find "Conversations" on this site, and members, do a search for milkweed. I left him pictures of my loop design, which included the spare pump center that I made.

    Make sure you buy the Grundfos Pump ending in 13 in the model number: Grundfos UPS26-99FC 52722513.
    If you buy the 52722512 it will be the 120vac version of the same pump. I bought two pumps on ebay, from Zorro, for $500. Shop around and don't pay too much.

    The UPS15-58 circulator pumps that didn't work on my unit are larger than your UPS15-42f pumps.
  16. bjl

    bjl Member

    I did a flow test. I did get p/t ports, but never installed them. I have p/t gauges on just about everything. They were cheap and I know it's not perfectly accurate, but it gives me a good idea. All my piping on the center is copper and the runs to the units is clear hepex. At my pump valves I have the air bleed ports. A coffee stir straw fits perfect in it. I put black food dye in the straw and put it in the water stream and timed the run. I measured out the 1" pex, fittings on unit, and sucked a string into the a/c coil to get its length (I wouldn't recommend the string, it's a pain getting out). A Lil math to calculate water volume and walla 6.5 gpms. That is on high speed with and without the factory check valve. 4 gpm lower than what it should be on my larger unit. The pressure just out the pump is about 6 psi and the return pressure from the unit is about 1 psi.

    If you add up the sq. In. Of 8 - 3/4" pipe, it is almost equal to a 2" pipe. So my loop field should be equivalent to pumping through 670' of 2" (in a 3' slinky). It took right at 200 gals of distilled water.

    The funny thing is the 1st pumps I had were 1/6 hp, but only single speed. I do have a swing pump. Do you think doing a push/pull configure would be good enough to get the additional al 4 gpm? The other unit is only 1 gpm low. It was working better than the other unit but still not dropping humidity like it should. Will this 1 gpm hurt anything?
  17. mrrxtech

    mrrxtech Member

    Maybe one of the Geothermal Pros can do a quick loop calculation using head loss from your information above to answer your question about using 2 pumps, mathematically. I could do it but I would need a quick review of Heat Transfer & Fluid Flow, but being more of a common sense person, I would go with the Grundfos Super Brute pumps that I mentioned earlier, here's why:

    If you put an amp meter on your Unit(s) compressor, you'll begin thinking about Unit performance in terms of electrical use. As you increase loop flow you will notice the compressor amps will drop off until the compressor is doing the same amount of heating or cooling for the lowest current draw/cost.
    You'll also be able to change your pump speed to it's lowest speed improving it's cost to operate as well.

    The ideal point of operation will be with minimum compressor amps and minimum pump amps to give the same performance results.
    This will change with heating & cooling seasons. Heating will need a higher loop flow rate than cooling. I wouldn't
    want to be limited on flow capability due to using pumps that cost less than $100, doing a job that takes a pump that costs closer to $250. Your savings in one month will buy the 1/6th horse power UPS26-99FC 52722513 pumps.

    I would use the two pumps in series push pull configuration. Notice that most flow centers sold use two pumps in series. There must be a good reason for using that design.

    You mentioned air removal from the loop. Take a look at the automatic air removal float valves on ebay, below. I used a Watts 1/8th pipe fitting float valve in my loop. The Watts shown has a larger pipe fitting than you need, it's just an example I picked out since it was being sold by Zorro, the place where I purchased the 2 UPS26-99FC pumps from, delivered free for $500 total.

    I can't find any 220 vac UPS26-99FC pumps (52722513) on ebay, but they will show up eventually. Don't buy the 512 model number or you'll have power issues since they are 120 vac pumps, as I mentioned in an earlier post. I use Nextag to find the best price but you probably have your own favorite search engine for that.

    Here are two examples, of auto air removal float valves you can put in a high point to remove any trapped air in your loops over time. My Watts valve also allowed air in when I had a low water level. It made an air rushing noise when my Unit shut off, letting me know I had a vacuum forming due to a void and needed to add some water to the loop.

    Maid O Mist Air Removal Valve: 291716268346
    Watts Air Removal Valve: 221553260717
  18. bjl

    bjl Member

    You are right. I took a couple hours today and threw that pump inline. Wish I would have read your post before doing it. I sure thought if would give me more gpms than it did. With both pumps wide open, drumroll, only 9.5 gal. Still a gal. Shy of my specs. I need a good volt/amp meter to test the compressor. I just bought a good volt meter and didn't think I needed the amp clamp so I opted out. I'm going look for your brutes. You are right, I think it needs it. I also bought a humidity meter. I think I may b pumping humidity in, maybe with my septic aerator. Ran one unit for 3 hours and dropped 8% humidity and 2 degrees. Turned off units and an couple hours later it was back to 73%.
  19. bjl

    bjl Member

    I didn't run the units last night so everything would dry up from bleeding the air out the lines. Checked for leaks this morn and all looks good. We'll at least no leaks, the sweats leave a "lil" to be desired. Well fired up units with a setting of 65*. Thought about doing a drip test on the condensate line. Went in the attic and disconnected lines to see what's needed. By the time I made it back, the bucket laying over catching what Lil water would be coming out had about a pint in it. I was surprised. About 5 to 6 min. Now this is the unit that was working better. By the time I made it to the larger there was pretty much a constant stream. In 30 min the larger unit, just over .5 gal and the smaller just under .5 gal. And humidity dropped 5%. The smaller unit air flow does comingle in the living room with the other units air flow. I wonder if the inadequacy of the larger unit was keeping the smaller from doing its job. To add to it the t/s is not in the best place from performance testing, but it's were the wife wanted it. And if I wanna get what I want she gets what she wants, lol. Now to finish back filling to get that ewt down some more. Ima have to leave the pumps as they r for the time being. Need to get more money together, but I like the looks of the higher gpm. I would have not thought I had that Lil flow for the larger unit. Thanks a bunch for all the info. As I move along I'll keep things updated.
  20. ChrisJ

    ChrisJ Active Member Forum Leader

    I built a new house in 2010, used open cell spray foam and had to put in poly on ceiling and walls for vapor barrier.

    It took a long time to get the RH down below 50%, I'm talking years. Had to run a large portable dehumidifier.


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