How much oil have I lost

memnosine

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?) 

hot_rod

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.

memnosine

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

expansion tank

It may be leaking into the expansion tank. Is there any swings in the PSI or is it holding at 12?

memnosine

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

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

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

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

Hydrin bladder a MUST....

If not, it WILL fail, eventually.



ME