Living and Learning with Geo

Discussion in 'Geothermal Heat Pump Testimonials' started by ChrisJ, Feb 2, 2011.

  1. ChrisJ

    ChrisJ Active Member Forum Leader

    The tech is saying the new low pressure switch that was installed in sept was 40/80 replacing one that was 25/50. Last week when his gauges were still hooked up he said he noticed low suction pressure when starting the unit back up and the cold radiant water(50*F) was being reheated.

    Unit was pressurized to 330psi then vacuumed down to 600 microns.

    Last edited: May 3, 2014
  2. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Damn Chris:

    I am with Joe.

    Did they use a scale?

  3. ChrisJ

    ChrisJ Active Member Forum Leader

    Yes a scale was used, both to take out what was in the system before the repair and after.

    The system was a little over charged because more then 6.11 lbs was weighted out, but using the same bottle to weight it in he came up short of 6.11, he got a new bottle and weight in the difference. Maybe some gets lost switching and purging.

    Obviously I am not a refrigeration tech but if the manufacturer says weighting in is just a starting point, I wish they would have spent more time making sure it's correct.

  4. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    Well weighing it in is going to be the right amount of refrigerant no matter what. That doesn't mean nothings wrong with the equipment, but the charge is right unless the tech didn't turn the jug over.
  5. ChrisJ

    ChrisJ Active Member Forum Leader

    Attached is Hydro-Temps charging instructions, I do understand that experienced HVAC techs feel they don't need to be told how to do this.

    This hybrid is an animal of a different kind. Dual compressors and the ability to heat air and water at the same time makes me wonder if charging needs to be done a little different or more precisely then single compressor units.


    Attached Files:

    Last edited: May 8, 2014
  6. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    That PDF was written by a guy that learned "super heat" not "sub-cooling" charging. I do both, and it is not clear to me what he thinks he wants the system to do.

    So I am with Joe if the guy that wrote the PDF was not the guy who determined what the "weighed" charge should be.

    Dealing with the charge for a geothermal system needs a fine hand. The target moves as you try to make the charge correct. An old beer, I meant bear, that thinks in multiple P/Ts in various refrigerants, can do a better job than a cub with the latest and great digital manifold gauge set. The weighed charge is good, but not the best.

    Each home and their systems is unique. Wow I spelled unique with out Bill Gates' help. What happens in the lab and gets typed in the I/O manual vs what happens when installed is not always the same.

    I consider you and I to be tequilas I meant of equal value. You have done much for this industry with your telling of your tales. Next time I am in the neighbor hood, for a shot and a beer fix this unit if it is not still leaking. I am beginning to think it was not before the fix.

    warm regards,

  7. AMI Contracting

    AMI Contracting A nice Van Morrison song Industry Professional Forum Leader

    It is true that weighed in charge may not be optimal. Manufacturers will try to save an ounce or two where they can as X's thousands of units this amounts to big savings.
  8. ChrisJ

    ChrisJ Active Member Forum Leader

    Thanks Mark and Joe!

    We are in the shoulder season here in RI, the unit only runs to heat my DHW. Uses between 6 and 10 KWH's depending on hot water use.

    Running at full capacity I see about 4.5*F delta T on the ground loop. The system has sensors that read refrigerant temps if those are important for diagnosis.

  9. ChrisJ

    ChrisJ Active Member Forum Leader

    I have been having trouble getting the PH level down of the water in the radiant system.

    The floor loops and buffer tank have been flushed 3 times.

    There must be a slime on the inside of the tank and pipes that when the water sits in there the PH goes up.

    New buffer tank? and pipes?

  10. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    I would treat the water. We just cleaned a system we started 10 years ago. The water came out green. We flushed all the loops and then added water treatment and a biocide.

    All the chemicals where made by Furnox.

    Last edited: Oct 28, 2014
  11. ChrisJ

    ChrisJ Active Member Forum Leader

    Loss of refrigerant again! Now the DHW heat exchanger. It was probably leaking when the radiant one was replaced.

    HT engineer said back in April we should replace both heat exchangers.

    I am sick over all this. My fault for running high PH water through both loops.

  12. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader


    I am sorry to hear about your luck.

    I have become a huge fan of making sure systems contain the best water available. I have been know to truck water to a job site. I also use PH up and down, like for pools and hot tubs to get water in a system neutral. The manufacturers publish water specs for a reason.

    If the de-super-heater is suspect and in fact needs to be replaced, I wonder what is up with the main coax.

    There are minimally invasive ways to test the refrigerant system for water and/or acid. One could "sniff" the DHW tank air vent with a refrigerant detector, and possibly rule out the DHW heat ex.

    What ever the out come, test and treat the water as you do not need this to happen again in a few years. I can hook you up with my Fernox rep if needed.

    If needed give me a call. 440.223.0840.

  13. ChrisJ

    ChrisJ Active Member Forum Leader

    He drew some water out of the DHW loop, it set off the sniffer tool.

    The ground loop should be fine, it was filled from my father-in-laws well, which has very good water.

    There is no desuperheater. It's strange, HT used a flat plate exchanger for the ground loop and a coaxial exchanger for the DHW. Radiant has a flat plate.

    I was thinking I would get something to lower PH in radiant loop, muriatic acid.

  14. heatoldhome

    heatoldhome Geo Student Forum Leader

    Wow that's interesting.

    Should water in a closed loop radiant floor system be tested for PH periodically? Or is once enough?

    Sorry Chris.
  15. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    It is very possible to grow things in low temp radiant systems. I test for PH and for growy things. Than act as needed.
  16. ChrisJ

    ChrisJ Active Member Forum Leader

    We are running the DHW off of electric elements still in the hot water tank. added a shut off to the loop plumbing so to isolate the DHW heat exchanger from the rest of the DHW system in the house.

    The installers office gave me a price replace the exchanger and it was a lot higher then doing the last one. I guess I should NOT have tried to be their "Little helper" right Joe!!

    When I questioned the price (via email) the Installer/owner chimed in and said "I feel you should cut your losses on this unit unfortunately. As much as you don't want us to be there we don't want to be there either."

    He sent a second email suggesting we abandon the DHW part altogether and use the elec elements or get a heat pump water heater. Which I could get for about $500 after electric company rebate.

    The tech mentioned re-plumbing the refrigerant lines to bypass the bad exchanger. He would pretty much have to do as much work as replacing the exchanger anyway.

    Maybe Santa will bring me a 7 series and a water to water for Christmas. LoL Or hit the lottery.

  17. ChrisJ

    ChrisJ Active Member Forum Leader

    I hired a company local to come in and bypass the DHW coaxial heat exchanger.

    Two guys, both knowledgeable refrigeration people. One was a trained Climatemaster tech.

    Last Saturday I put Fernox cleaner in the radiant tank. I spoke at length with tech support at Fernox. He said the cleaner could be left in for up to 2 weeks, even though the can says minimum 1 hour. The can really had no directions at all.

    I left it in for 3 days. I drained the tank and flushed the system 3 times. Then added the F1 protector chemical.

    Now I will look into a heat pump hot water heater to replace the electric tank. I will save the tank for a buffer tank down the road if/when I have to replace the entire unit, to use with a DSH.

  18. ChrisJ

    ChrisJ Active Member Forum Leader

    The Fernox cleaner and inhibitor didn't work, water still returns to a high PH. The tech at Fernox asked me to send water samples, one from the radiant loop and one from the tap. Have not heard back yet.

    Maybe I didn't use enough cleaner..... How many gallons of water in 1800 ft of 1/2" pex-al-pex?

    The stuff is expensive. I need to do something though because I don't want to wreck the second heat exchanger.

    Last Saturday I had the electric HWH replaced with a GeoSpring HPHW. Seems to work good. It does noticeably lower temp in the utility room. The room is not totally closed off to the basement, the open risers of the basement stairs let air migrate into the basement. I think it is making the radiant zone turn on more often.

    Checked the sensors this morning, I really am not looking for trouble but not sure the charge is what it was (leak). The LAT was only 84*F, EAT 68*F. Sensors say only 1.7*dt on the ground loop. Not sure I trust those sensors completely they have been on and off the pipes.

  19. heatoldhome

    heatoldhome Geo Student Forum Leader

    I believe about 118' of 1/2" pex will hold 1 gallon.

    so 15.25 gallons in 1800'
  20. ChrisJ

    ChrisJ Active Member Forum Leader

    Low on refrigerant again. Couldn't find a leak with sniffer.

    He left a little 410A in the system then charged it with nitrogen, hoping the extra pressure would get the sniffer to sniff it out, no luck.

    Tried taking some water out of the radiant system but he didn't get any good hits from the sniffer.

    Noticed a little air venting out of the radiant for the last couple months, may be refrigerant. Meaning the second radiant exchanger is gone after less then a year.

    So it's kind of decision time, put another exchanger in (2K +/-) or start over after only 5 yrs.

    Waterfurnace synergy 3d is the most likely replacement. The Boss says we will not be getting another Hydro-temp, though the replacement would be much easier. Warranty is much better with WF.

    Mark Custis likes this.

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