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How much oil have I lost

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memnosine
memnosine Member Posts: 7
in Solar
I'm losing pressure in a solar Bray oil system, and haven't found a big leak. But how big a leak would account for this: I've lost 4 psi -from 16 to 12- in two months since repairing a cut line on the roof (long story). I have six each four-by-eight foot arrays, and three each one-by-two meter arrays. I've found a leak of about one drop in a week or two; how fast must a leak be to account for the loss I'm seeing? It's not in the heat storage tank (at least I don't think so, this oil is lighter than water, isn't it?) 

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  • hot_rod
    hot_rod Member Posts: 22,139
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    total system volume?

    it would be tough to guess without knoiwing how much the system holds, how much actually leaks, etc.



    I would think any DHW coil or HX would have double walled heat exchangers and the oil would be visible, via a leak path, before it could cross into the potable water supply.
    Bob "hot rod" Rohr
    trainer for Caleffi NA
    Living the hydronic dream
  • memnosine
    memnosine Member Posts: 7
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    Bray oil next step

    Thanks for the comeback.  The oil -it's really a high temp hydralic fluid-  is not getting into the house water. The fluid in the transfer tank is clear, no oil sheen. I've touched almost all the pipes, joints, and find no drip. It's a mystery I'd like to solve.  Is there a sniffer like for natural gas? Someone who specializes in this?
  • michael_34
    michael_34 Member Posts: 304
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    expansion tank

    It may be leaking into the expansion tank. Is there any swings in the PSI or is it holding at 12?
  • memnosine
    memnosine Member Posts: 7
    edited March 2012
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    Pressure swings

    The pressure changes with the temperature of the oil, from a low of twelve at night to a high in the low twenties during a sunny day. I've extracted the data for the residual pressure when the array temps are from below forty and plotted the accompanying pressure, as attached.
  • memnosine
    memnosine Member Posts: 7
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    pressure swings

    It appears that the attachment dis not make my last post; I'm pasting the data here.

    ----------------------- Page 1-----------------------



                                                                        Sheet1

    Date               Array #1           Pressure



                                       38                 16



                                       38                 16



                                       33                 16



                                       31                 16



             Feb 03                    27                 15



                                       31                 15



                                       27                 16



             Feb 04                    38                 16



             Feb 08                    17                 14



                                       31                 15



             Feb 09                    28                 15



                                       32                 15



             Feb 08                    17                 14



                                       31                 15



             Feb 09                    28                 15



                                       32                 15



             Feb 10                    30                 15



                                       26                 15



                                       24                 15



             Feb 11                    24                 15



             Feb 12                    16                 14



                                       22                 15



                                       22                 14



             Feb 13                    26                 14



                                       28                 15



                                       34                 15



                                       32                 14



             Feb 15                    32                 14



                                       34                 14



                                       30                 14



             Feb 16                    37                 15



                                       31                 14



                                       32                 13







                                       24                 13



             Feb 18                    33                 14



                                       37                 13



                                       28                 12



             Feb 19                    25                 12



                                       25                 12



                                       24                 12



                                       24                 12



                                       27                 12



                                       32                 12



                                       34                 12



             Feb 20                    30                 12



                                       35                 12



             Feb 23                    28                 12







                                                                         Page 1





    ----------------------- Page 2-----------------------



                                                                       Sheet1







    Feb 26                        17                   12



    Feb 27                        38                   12



    Mar 06                        30                   12



    Mar 10                        32                   11



    Mar 13                        39                   12



    Mar 19                        26                   12



    Mar 20                        28                   12







                                                                       Page 2
  • michael_34
    michael_34 Member Posts: 304
    edited March 2012
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    New Expansion Tank

    It is more than likely your Expansion tank is failing or not sized properly. First check and make sure that the air bladder of the tank is pressurized to the pressure. If you keep your system at 30psi, then the bladder should be 3-5 PSI lower. I have seen the wild swings handful of times on systems. It not unusual for this to happen.



    Always make sure the expansion tank is rated for solar temps.



    Good luck

    Michael
  • memnosine
    memnosine Member Posts: 7
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    Stable now, close the thread

    I've checked every pipe, every joint, each array, and checked the tank and the heat exchangers. No oil leaks anywhere. Pressure has stabilized at 11-12 psi. How do I close this thread?
  • Mark Eatherton
    Mark Eatherton Member Posts: 5,853
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    Hydrin bladder a MUST....

    If not, it WILL fail, eventually.



    ME
    It's not so much a case of "You got what you paid for", as it is a matter of "You DIDN'T get what you DIDN'T pay for, and you're NOT going to get what you thought you were in the way of comfort". Borrowed from Heatboy.
This discussion has been closed.

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