Washington Hp Home DIY Geothermal

Discussion in 'Geothermal Heat Pump Testimonials' started by Hp Home, Dec 30, 2015.

  1. Hp Home

    Hp Home Member

    That's cool how he made his own press for the plates but thinking about the time involved I am now glad I bought them.

    I think all the plates I bought was around $500 so not too bad really. I wonder how the solar collector plates compare.

    Under the tile in the master bath I did the diy plywood sleepers on the floor just like the solar shed.
  2. Hp Home

    Hp Home Member

    Little questions about installation and plumbing are starting to accumulate in my mind as this takes shape.

    With my 3 ton system running 9 gpm should I pipe with 1-1/4"? The equipment has 1" connections but I think the head loss will be a little high if I use 1" pipe?

    I have 3 manifolds in the house. One of them is served by piping that runs up the wall, horizontally through the floor joists, then down to the manifold. I was thinking this configuration could potentially cause an air trap? I'm wondering how big of deal this is or if its worth worrying about?

    I understand that piping from the hot buffer tank to the radiant zones should be "generously sized". How generous? I have 1-1/2" pump flanges, then 1" pex run to each manifold. Should piping be 1-1/2" through the circulator and then use 1.5" x 1.5" x 1 tees?

    Dielectric unions- when and where to use them?

    I'm sure my questions completely expose my lack of experience, now watch me learn the hard way. And hopefully any information generated here will help others in the future.
  3. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    What you need is a table to tell you how many BTUHs fit in a pipe size. My favorite is located in "The Heating Helper" by US Boiler Company, www.usboiler.net
  4. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Boilers are not heat pumps. Boilers work with high delta T and lesser flow, heat pumps work with more flow but lower delta T. Thus the size of the pipe to transport the BTU must be much larger for geo than for a boiler, if you want the system to run efficient.

    Yes, 1.25" pipe is a good size for 9 gpm. The velocity is high enough to purge any air out.

    Also between HP and buffer and manifold, 1.25" is enough for 9 gpm.

    BTW, consider "load direct" or "buffer tank bypass" piping. It will save you roughly 10% operational costs due to lower entering load temperature.
  5. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Gee I did not know that there are different thermal laws for hot water and warm water. I would think the thermal-dynamics would be the same.
  6. Hp Home

    Hp Home Member

    I had a feeling 1.25 was the way to go.

    Looking at the chart in the heating helper 3/4" pipe would move enough btu's. They must be rating at a higher temp water?

    So where there are fittings, flex hoses, and valves that are 1" does the water just move faster in those spots? And the 1.25 pipe provides less restriction everywhere else to reduce overall head loss?
  7. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    The water temp does not matter, only the heat transfer. Read the fine print below the table. Most of the manufacturer printed and provided tables assume crude filled cast iron pipe. The tables where then reviewed by lawyers not plumbers.

    There is a few tons worth of fudge space in what you see. I run the system sizer wheel at 20% to my favor. Slick plastic and pex increases the flow too.

    I would have you consider two additional ideas before heading to the BIG BOX. In stead of copper look at CPVC. It is CTS, (copper tube size) so it will carry an un-measurable amount less flow than IPS, (iron pipe size). You thought copper so flow is the same.

    Second, test and treat your water. Both sides of the heat pump.

    I am going to put on my tin foil hat and be on the look out for flying plastic Buffalo chips.

  8. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    BTW, If I knew why they install 1" fittings in systems that needs larger flow I would not be waiting for Orange people to show up in Cleveland.
    Last edited: Jul 15, 2016
  9. Hp Home

    Hp Home Member

    Is it ok to use cpvc? It would cost a lot less than copper. Climate master says no pvc because it will corrode and ruin the heat pump, I had assumed cpvc would also be a no no.
  10. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Climate Master is wrong. How can inert plastic corrode copper plated steel? A system using PVC might sag or melt fittings. I had a system loose a pump and melt sced 40 PVC as it is only rated for 140*F.

    I meet the guy that invented CPVC. He lives in Vermilion, Ohio. He was working for BF Goodrich at the R&D plant in Avon Lake, Ohio. He can make real neat stuff. What BFG sold in its Rold Gold line to Creston, only goes to 180*. That is almost enough to handle some BOILER SYSTEMS, (I can not help myself).

    I like to support the plastic at about 60% of the OC distance for copper.

    Need more let me know.
  11. Hp Home

    Hp Home Member

    I think it was something to do with an antifreeze chemical reacting with pvc and contaminating the water. Not sure which type of antifreeze it was but I always take note of the 'voids the warranty' type of warnings.

    I do need lots more and I appreciate the help.

    Another pipe sizing question I have is regarding "generously sized" header piping serving the radiant zones. Is the idea here to just go up a size, like say 1.25 to 1.5?

    Where this header pipe tees off to the three manifolds do these tees need to be 'closely spaced'? Currently I have them stubbed out of the ceiling about 18" apart.
  12. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Do you have ClimateMaster toys? It does not mater we want to use CPVC. Find me the "VOID" and I will read it.

    I know this will wake up the "well known expert". I do not think spacing of "T"s is a killer unless you are building a "true" primary secondary loop system. Draw me what you think you want to do and send it or post it here. I have folks trying to prove me incompetent. so I keep my knowledge to my self more than I should. It does occur to me since my days of doing this stuff is over I can give away my knowledge without loosing money.

    Without a drawing or a picture, it does not matter where the stubs are. Pipe them to closely spaced "T"s on the primary loop. No more than 4 time pipe diameter O/C on the "T"'s.

    My wife just broke her other wrist so we have two hands and two feet between us may need a day off. I hate ERs, except when I am the patient.
  13. Hp Home

    Hp Home Member

    I'm sorry to hear about the injuries, hopefully you can at least park right in front when you go shopping.

    Yes toys are from climate master, TBW036. Although as a DIY installer I think I am SOL on warranty support anyways. Unless I find a pro willing to certify my work with their good name.

    I can do a drawing tomorrow but I think I know what needs to be done. Space the tees closely then pipe it to the stubs.

    Thanks again for the sharing of knowledge. I'm fascinated by this stuff and love soaking up all the info.
  14. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    To HpHome:
    Obviously the water temp matters since the hotter the water the more thermal energy is stored in the water.
    For the heat transfer, 2 things matter, which are the temperature difference between ingoing and outgoing water (in this case the water going in and out of your radiant system) and the amount of flow (plus a constant, which is 500 for pure water.


    Page 27
    "HR = TD X GPM X 500, where TD is the temperature difference between the entering and leaving source water, and GPM is the flowrate in U.S. GPM..."
    While this specifically refers to the heat transferred from the heat pump to the loop field in AC mode, the principle is the same for heat rejected from the heat pump into your radiant system.

    No modern heat pump system should use close spaced Tees for the distribution manifold. Why would you pay a performance penalty to make your water hotter only to cool it down with the return water from the first zone before you send it to the next zone with the next closed spaced T? You should have one manifold for the supply and one manifold for the return so water does not get mixed.

    Close spaced T had a place in old boiler design where you could make 180F water and did not care if it was cooled down by 20F by the time it got to the last T on the manifold.
    Now modern geo system's efficiency depends on the water temperature the heat pump has to deliver, the hotter the less efficient. Thus the colder temperatures you can supply the water the more efficient the heat pump is.
    So the key for low temperature radiant heating systems (like radiant floors or radiant walls) is to run the temperature as low as possible to satisfy your thermostat and to have higher flow, and to have even temperatures enter each zone (which is not possible with closely spaced Tees). We shoot for 90F to enter the radiant system, for surface temps of the floors in the low 80s, in newly designed systems, on the coldest day of the year.

    Here is an example how it can be piped efficiently and simple:

  15. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    Do you take nice pills?

    Water temperature does not matter for the amount of heat transferred.

    I do not think it matters if you like primary/secondary piping. it is not your system or money. Maybe a hydronic separator would work.
  16. Hp Home

    Hp Home Member

  17. mtrentw

    mtrentw Active Member Industry Professional Forum Leader

    That is an interesting warning on page 8. It warns against PVC use on the water side because of the potential damage from the POE oil in the R410A refrigerant. It'd take a coil failure to allow refrigerant into the water side at which point oil could damage PVC.
  18. urthbuoy

    urthbuoy Well-Known Member Industry Professional Forum Leader

    I'll just go on the record and say closely spaced T's have a lot of current value. Systems with different load requirements both in temperature and flow can simplify immensely with hydraulic separation. Boilers, geo, solar combo's. Domestic, snowmelt, radiant floor, etc.
  19. Mark Custis

    Mark Custis Not soon. Industry Professional Forum Leader

    HP Home's drawing is what I learned as a European Ladder. It in fact delivers the same temperature water to all three heat emitters.

    I like Trent's point. If you are mixing POE oil in the loops you have bigger issues than damaging the PVC piping.
  20. docjenser

    docjenser Well-Known Member Industry Professional Forum Leader

    Well, not so fast.
    I did say that the delta in the temperature is key for the heat transfer (eg how much temp is lost to the zone), as well as the flow, plus a constant for every medium (for water it is 500). Now the delta T is dependent on how much the temp delta is between the radiator and the zone. At the same flow, a hotter radiator will transfer more heat into a zone than a colder one, because the delta T between the zone and the radiator is higher.

    You were looking for tables to look at "how many BTUs fit in a pipe size" which has nothing to do with heat transfer. I can transfer more heat through 1" pipe than through a 2" pipe if I want. The key question is: At what temperature of the fluid, and how much of that temperature can I reject or extract? And at what flow rate? And what is the heat transfer capability of the fluid.

    Heat transfer is defined as:
    Heat Extraction or Heat Rejection (in BTUs) = Delta Temperature (in F) x Flow (in GPM) x Heat transfer coefficient (500 for water)

    Nothing to do with the size of the pipe.

    This is why the tables on your heating help website you referred to, has specified the delta T and the GPM (either directly or indirectly).

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