Water clarity for steam boilers - how clear should it be?

stevep

I have a one pipe counter flow steam system from 1934. We installed a new Crown boiler a couple years ago and the system runs beautifully. The boiler has never been blown down so I recently started taking out a couple pints at a time while the system is under normal operating pressure (~1lb). The water comes out brown and full of sediment when it's firing, and by now I've probably taken out 5 gallons total and I haven't noticed much of an improvement in clarity although the site glass is now pretty clear when the system is firing. Once the boiler cools and the sediment drops out of suspension the water is crystal clear. I'm not too keen on doing a 5-10psi blow down because 1) there's no king valve on the system; and 2) pressuring the system like that scares the hell out of me.



Should I leave it be? Or should I stay the course in a quest for clearer boiler water? Again, the system runs very very well - there's no surging, no water hammer, and I can go an entire heating season without adding additional water to the boiler. I just like tinkering with the system and want to keep it in as tip top shape as can be.

ChrisJ

Cleaning

I recommend building a wand and giving the boiler a good washing.  I hook mine to the drain on my water heater so I get good hot water.

You can use a bucket to catch the drain water and then carry it out side or dump it in a slop sink if possible.  Afterwards I recommend using a minimal dosage of water treatment, either Rhomar Boiler Pro 903 or Rectorseal steamaster tablets. 





Here is a thread on building and using a wand.

http://www.heatinghelp.com/forum-thread/143078/Rinsing-the-boiler



Ever since I cleaned with the wand and started using the steamaster tablets my water stays very clean.  I still have not drained any water this year because I don't see a reason to.  I had planned on doing a cleaning but once I noticed the water was still pretty clear when steaming I decided to just ignore it for now.



Before using the wand and Steamaster tablets

http://www.heatinghelp.com/images/posts/14746/resize_DSC03680B.jpg



After

http://www.heatinghelp.com/images/posts/15017/resize_purple.JPG

stevep

Thanks Chris

Lots of good info in those links. My sight glass isn't nearly as cloudy as yours was before the washing so maybe I can get away without having to do a full washing. I'll get some pictures of the water samples and sight glass so you guys can have a look.

BobC

Skim?

You might try a nice slow skimming on that boiler before going the full bore cleaning route, if that doesn't work then  a thorough cleaning is in order.



Steam boilers are not usually known for clean water without some sort of agent added to the boiler water because the nature of the system is that hot water and iron creates rust. This usually results in tea colored water at best.



i've used Steam master tablets and the water is as clear as a bell, albeit purple tinged.



Bob

stevep

Skimming

Bob, I didn't think that skimming would be applicable for this situation because the sediment is heavy and therefore settled at the bottom of the boiler. When the boiler was first installed I had to skim it several times to get rid of threading oil so I'm familiar with the process.



Chris, when using the wand are you mostly aiming at the top or the bottom of the block casting?



Thanks guys. Just trying to understand the logic.

ChrisJ

Aiming

You aim everywhere. Back, side, top and bottom. I cleaned mine starting with the top and upper sides of each section. Then I slowly worked my way down until I was finally cleaning the bottom until water ran clean. After that I skimmed for a bit just in case.



Since then my water has been spotless of course with the help of steamaster tablets.

stevep

Washed the boiler tonight

I had to make up a small 3/8" wand because my best access was through the 3/4 NPT drain port. I drilled holes in the nozzle to get a multi-directional spray. Probably flushed 75-100g through the system in total.



I tried to use a standard spigot valve in reverse direction but discovered it can't run that way, so I used the water heater spigot instead to control flow.



The pictures show a dirty water sample in a glass, the dirty water I flushed out, and a clean water sample in a glass after the washing.



Chris, how many Steamaster tablets are you running? I put in 1.5 tablets and my water is much less purple than yours.

BobC

Check the PH

Well it looks like your washing worked out well.



I have a Smith G8-3 boiler and the one steammaster tablet I used brought my PH up to 11 and the water has a very light violet tinge to it, I drained a couple of gallons and added water to bring that down to 10. That tablet was added a year ago and the water is still as clean as a whisle in the sight glass and out of the mud leg of the boiler.



Bob

ChrisJ

Reminds me

I still want to get my hands on a decent quality electronic PH tester. I'm not sure how much I trust the paper stuff.



I guess its not terribly important as long as I'm above 8 and below 11 though.

stevep

PH

I haven't checked my PH yet because I can't find my my test kit. I'm going to run to the local aquarium store today and see if they have a decent one for short money. I used to have a saltwater reef aquarium and from my experience PH is an easy parameter to check with a simple test kit. An electronic probe would probably be overkill, I'd look more at something like this:



http://www.marinedepot.com/Aquarium_Pharmaceuticals_Aquarian_Freshwater_Deluxe_pH_Test_Kit_250_tests_pH_Test_Kits_for_Freshwater_Aquariums-Aquarium_Pharmaceuticals_API_MARS_Fishcare-AP3213-FWTKPH-vi.html



I never really trusted litmus tests that much. Guess I just had too many problems checking swimming pool water parameters with them.

Mike Kusiak_2

pH paper

Chris, I would trust test paper more than an electronic meter. There is so much more to go out of calibration with an electronic meter, compared to the simple color change of a chemical reaction.



I have a box of pH paper that is at least 40 years old, which still indicates perfectly accurately with known concentration test solutions.

ChrisJ

paper

Mike,



What concerns me is the paper I have reads from something like 0 to 13 and its so hard to tell the difference between 9, 10 and 11. Also I noticed any paper exposed changes color over time so I'm assuming that means its no good?





http://www.webstaurantstore.com/images/products/main/44777/25488/hydrion-93-s-r-insta-check-ph-test-paper-dispenser-level-0-13.jpg

BobC

PH

Most aquarium test kits have very small ranges, you need something that can test up to 11 or 12 and as Chris said you want to keep the PH between 8 and 11. I picked up a bottle of test strips for about $15 from AMAZON that covers a range of 4-12. An electronic tester would be nice but I'm not sure it's worth it for just this.



Bob

stevep

Good point

Good point BobC.



Hanna is now making a low cost electronic probe that gets favorable reviews:

http://www.marinedepot.com/Hanna_Instruments_Checker_pH_Pen_Single_Item_Monitors_Controllers_for_Saltwater_Aquariums-Hanna_Instruments-HN1135-FITEMOID-vi.html



Might be worth investigating for $37.

Mike Kusiak_2

Paper

The paper will fade if exposed to sunlight or UV, so I keep it wrapped in aluminum foil and then in a sealed container. Just tear off the exposed portion and use the fresh paper underneath.



The other caution is keep it away from any acid fumes, since with humidity it will indicate presence of an acid.



As you said, the paper covers a large range, but I don't think an exact reading is really necessary. You really just want the water slightly basic, but not excessively so.

Mike Kusiak_2

Alkaline test paper

Here is a paper which covers a narrower alkaline pH range which might be more suitable for boiler water:



https://www.microessentiallab.com/ProductInfo/F01-SHTRG-065130-SRD.aspx

ChrisJ

TDS

Mike,



Last year I checked the TDS of my wet return and found it to be around 2. To me, that suggested I was producing very dry steam as I assume wet steam would carry dissolved solids down the mains. The boiler water had a TDS of around 500.



Does that sound like a fair assumption?

Mike Kusiak_2

Seems reasonable

Really what you are doing is producing distilled water, so any dissolved solids in the condensate would probably originate from carried over boiler water

stevep

Thanks

I just ordered these which appears to be the same thing you posted Mike, but available in a single unit quantity.



http://www.amazon.com/dp/B0045I6IE0/ref=biss_dp_t_asn

ChrisJ

Yeo

That is where I bought it last year.

Thing is, now I want to get the ones Mike posted as it seems like it would be far easier to tell whether I'm at 9 10 or 11. I like to keep my water around 9.

Rod

Boiler Water PH

Nice cleaning job, Steve !    I like your wand nozzle arrangement! It’s perfect for those boilers that have a mini skim port.



On boiler water PH, keep in mind that the PH scale is logarithmic.  A PH of 7 is neutral. A PH of 8 is 10 times more basic (alkaline)  than a PH of 7. A PH of 9 is 10 times more basic than a PH of 8 (meaning that it is 100 times more basic than a PH of 7!!)  Once you go above a PH of 8 you are well into the alkaline area. I myself use swimming pool test strips which only go to 8.5.  I figure if the color is at 8.5 or darker, my boiler water is well alkaline and is okay.



PH meter- I think I would have to agree with others that a PH meter may be more problems than it is worth. My experience with meters of this type is they are great if you use them every day. Using them everyday you get a feeling when the meter’s reading doesn’t seem right (malfunctioning ,out of calibration). I don’t think that would be so if you just used the meter once a week/month.

Just my 2 cents worth.

- Rod

                        

ChrisJ

True

Very true Rod however remember a high PH will not harm metal and as long as its below 11 shouldn't cause foaming problems.



I have heard of it etching the gauge glass though. I'd rather replace a $5 gauge glass than a boiler though. I like 9 because it gives it plenty of room to drop over time without risking harm because we know the return water is always slightly acidic.

stevep

Checking PH

Are any of you guys concerned that the purple tint from the Steamaster tablets affects the color reading of the PH paper?



My water is still nice and clear by the way.

ChrisJ

Yep

That is something that I've wondered about for a long time.

Yet another reason to get a quality electronic PH meter.   Whether you have clear purple water or rusty untreated water its a problem for the strips IMO.