Salt/Water mixture to calculate hydronic volume?

Unknown

I've inherited a radiant system (done by others) which has a corrosive water condition in the systemic fluid. This system has been plagued with telestat actuator failures, gasket leakage and corrosion is present on a number of components within the system.

I had the boiler water tested by Rhomar Water management and they recommend cleaning and flushing the system then treating to prevent further damage.

Since there is no way to mathematically calculate the volume of fluid in this system holds, (embedded tubing in concrete w/ no documentation) the following was suggested;

"1.   Thoroughly mix 4 oz. (by weight) of table salt in one quart of distilled water. A letter postage scale can be used to weigh the salt.  It is critical that the measurements of salt and water be accurate.
 
2.  Add the quart of distilled water and salt to the system.
 
3.  Open all zone valves and circulate the water for one day to blend the system water and salt solution.
 
4.  Take a pint sample of the system water and send to Rhomar for testing. 
 
We will be able to measure the amount of salt in the sample and calculate the quantity of water with a fair amount of accuracy.  Otherwise we will have to guess based on the size of the circulating pump.  We can follow up with tests after the Rhomar 922 has been added and make any adjustments then."

Any suggestions as to a method I should use to introduce such an exacting amount of fluid without ANY hose losses. It's always tricky to inject all of a substance into a closed loop system. I'm never able to draw that last little bit of fluid from my bucked with my Silver King force pump. The fluid remaining in the hose and pump never make it into the system.

Any suggestions?

Gary


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scrook_2

amount of fluid

added doesn't matter, the amount of salt DOES. can you flush ALL the salt water in w/ more distilled water say two or three more quarts? Also, before you add the salt extract a baseline sample of the boiler water in case there are already any traces of salts in it.

hr

How accurate

do you need to be? Could you fill and purge the use a compressor to blow doen the contents into a barrel?

Generally I will add a resonable amount of treatment, then come back and retest in a few days. Boost as needed, if needed.

The important part is a good cleaning. error on the safe side with the cleaner. The size of the building and content of the boiler and near boiler piping should get youy very close.

Siggy's Hydronic Design Studio has a program that will calculate system volume, for the piping you can see. Tubing unknowns shouldn't upset the total by huge amounts, as you must at least know the diameter of the tube used? Run the figures at 6" and 12" oc tube spacing for some possible ranges. Rarely will you see much 6" oc jobs.

hot rod

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Unknown

Hey hot rod,,

I don't need to be that accurate. Not looking to be perfect. Just shooting for the high 90s.

I understand that you were involved with the development of the Rohmar product line. Nice guys there. Smart.

I'm looking for a better way to inject solution into a closed loop system without any loss. Any suggestions?

Gary

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Mark Eatherton1

I believe...

the best way would be to isolate the boiler from the rest of the system (if possible), drain off excess pressure, remove relief valve, drain one quart out, pour quart of salt water in through relief valve tapping, re-pressurize and let 'er rip.

I remember reading those instructions on a boiler chemical container, sans let 'er rip...

ME

Drew_2

Salt/Volume

Gary, You can do the same thing using 1 gallon of Propylene Glycol. Might be better than adding salt to the fluid.

1. Make sure there is no PG/Antifreeze in the system. If there is you will need an accurate reading.
2. Add 1 gallon of PG to the system.
3. Send me the sample for testing.

Drew

mph

Gary

Hook a centrifical pump to the system with a hose leading back into a 5 gallon bucket. Prime the pump by back-filling the bucket through the pump intake with the boiler solution. Add the salt/water solution to this and pump into the system. Let it circulate through the boiler and all zones for as long as possible. You can shut the pump off, close the drain valves and let the system run over night while leaving the pump and bucket in place. The next day run the pump for a while to equalize the sample in the bucket. Take a sample from the bucket to send to Rhomar. Then subtract 5 gallons from their calculated volume.

The ratio of salt to water in your added mixture is critical. The larger the volume of fluid in your system, the more error in the calculated result if your ratio is incorrect.

Good luck,

Jeff