Testing Oygen Levels in a Closed Water System

OfficeGuy831

Hello all, looking for help on either testing equipment or procedures for testing oxygen levels in a closed water hydronic heating system. We are testing the theory that there is oxygen introduction via stainless steel water flex lines - thus causing premature corrosion of this pressurized equipment from being exposed to an oxygen rich enviroment.



Any ideas, theories, or practiced knowledge is greatly appreciative...additionally, a source on a quality water connection with effective oxygen barrier would also be helpful!!



Thank you all in advance

Jamie Hall

There are

a number of chemical analytical methods available for deteriming the dissolved oxygen levels in water; they are available from any quality water testing laboratory, and are quite routine.  There are also a number of analytical instruments manufactured which can be used for rapid testing, based on various electrodes.  While those do require calibration by one of the Standard Methods, they are suitable for continuous use in a closed pipeline (some have means for withdrawal for calibration under pressure).

Mark Eatherton

I hate to tell you this, but...

Oxygen can NOT diffuse through a metal. No how, no way.



It can get through rubber and plastic, but absolutely not metal.



Barking up the wrong tree...



ME

OfficeGuy831

Did I say diffuse though metal?

"Cannot diffuse through metal"  - didn't say that...There are stainless steel flex lines...similar to what you might see connected for supply lines to a sink for instance...not solid steel or otherwise metallic hose - there is an internal plastic hose that for all intensive heating & pressure purposes are adequate for the transfer of water in these closed system, however we are working on the theory that these stainless steel REINFORCED water lines may be allow oxygen introduction into the system - we would like the count the oxygen ppm for instance to either confirm or negate this theory...



So, thank you for the information with regards to testing equipment although a manufacturer, or some direction to follow in finding this information would be helpful. I have been looking into some of the local water treatment & testing companies but have not yet been able to speak to someone directly regarding this. Any further information would be greatly appreciated!

Jamie Hall

Testing equipment

I quite deliberately did not include the names of manufacturers of testing equipment for dissolved oxygen -- for a rather simple reason: I have found in the past that use of the equipment by those not trained in its use and calibration (like the use of any other precision testing device) can lead to erroneous and misleading, if not downright wrong, results.  In my opinion it would be better that the testing be performed by a laboratory properly qualified and licensed to do such testing, particularly if the results are to be used for anything other than casual purposes.  I have gotten very good results in the past with YSI instruments, but there are other manufacturers as well.

LarryC

Back to basics

How do you intend to prove the source of O2?

Why don't we back up to the beginning?

 

1)  What is the closed system for?

2)  What is the system pressure?

3)  Are you pumping away from the Point Of No Pressure Change (PONPC) ?

4)  What type of expansion tank is present?

5)  Any water treatment chemicals in the system?

6)  What is the water pH ?

7)  What are the system materials ?  Copper pipe, galvanized steel, stainless steel pipes, plastic radiant floor tubing, rubber hoses, etc.

8)  Are there any leaks you can see?

9)  Does the system maintain pressure ?

10)  Is the make up water line turned on ?

11)  What type of heat source ?  Electric boiler, water heater, oil burner, gas burner, solar collectors, geothermal heat pumps, etc.

 

All of these items can lead to increased corrosion in a water system.  The corrosion could be coming from air migrating into the system thru tubing walls, pump suction being below atmospheric pressure, or leaks causing excessive make up water bringing in fresh oxegenated water.

Higher temperatures can accelerate the corrosion process.  Dissimilar metals in electrical contact can cause corrosion.  Incorrect levels of  water treatment chemicals or overheated chemicals can all create problems.



Let's step back and look at the whole picture, before zeroing on something that may or may not be the cause of the problems.

Larry C

Mark Eatherton

Miscommunication....

When you say stainless steel flex connector, I am thinking in my head, a stainless steel corrugated pipe, which can not pass oxygen through its walls.



Are you a lawyer, or an attorney, or are you working for a lawyer or an attorney?



ME