White scum inside water jacket?

[warno]

I opened a port in my water jacket this morning to check something else and I noticed a bunch of white "scum", I would call it, all over my heat exchanger surfaces inside the water jacket. Is this my anode breaking up or causing potential problems? I have been treating the water with a nitrate treatment since I've been running in November would that have anything to do with it?

Thanks for any help in the matter.

 

[cumminstinkerer]

Warno, I wonder if its mineral deposits, it could be the anode though as well

 

[TCaldwell]

Take a sample to a lab, usually when's anode breaks down there are deposits under the rod, on the garn the white film is mineral deposits

 

[warno]

So material deposits, is that like hard water deposits? Or is it my steel breaking down?

 

[TCaldwell]

hard water deposits

 

[warno]

How do I keep this from happening? Well it hurt anything in the long run?

 

[__dan]

As you heat water, the minerals in in tend to precipitate out as a factor of lbs/btu heated, and stick to the wall of the heat source. This is why tankless coils have a tendency to plug up and tank heaters have a procedure for cleaning.

On a closed loop system, the initial mineral content load in the water is relatively fixed compared to a system that runs on constant fresh makeup water. So it's not a problem that runs to infinity. It will run to its constant steady state as long as the system is run closed loop.

As far as how much of a problem or what to do about it, it's beyond my expertise. Doing nothing may be one of the options, after the problem has been more researched and explored. Mineral scaling by itself may possibly be benign as long as it does not plug up any passages, but corrosion would be potentially catastrophic, and is its own specialty.

 

[tom in maine]

I would expect this is either the nitrate treatment and/or some oil that was on the steel you used.
It is unlikely that there is any mineral content of any consequence in the system.
I believe that scum is usually due to poor cleaning/ oil residue.

 

[warno]

When I started the system I ran this stuff through it.

(broken link removed)

I've been trying to get the nitrate levels right since the get go. The paper work says to maintain 1500-2000 PPM the best I can get is 950.

 

[Fred61]

You might want to check the PH if you haven't already done so. By trying to balance the nitrite level you may be raising the PH beyond reasonable levels. Do you know the hardness of your water? A light coating of calcium should not pose a problem as long as you are not continuously adding or changing the water.

 

[warno]

I haven't added any water since startup around thanksgiving. I'm not sure on our water hardness. I'll get my PH checked soon as I can.

 

[warno]

I borrowed a PH level tester and if I'm not mistaken I think my levels are off the charts. What can I do to drop my PH?

I did the strip test and here's the result.



And I also did the drop test, again the results.

 

[hondaracer2oo4]

You need to get a kit that tests higher ph levels. My heatmaster requires 8.5 to 10.5.

 

[warno]

Oh wow. I didn't realize that would even be ok. Is that an open system?

 

[hondaracer2oo4]

Yes open system and the nitrate level is suppose to be no lower than 730 ppm and the conductivity is suppose to be 100-4000.

 

[Fred61]

Warno, Have you made any progress on the PH levels? I don't know much about required levels and it appears that Honda is much more knowledgeable, but 10.5 seems awfully high to me. Also, knowing little about what chemicals are available for boiler maintenance, my first thought would be to use citric acid which is available in spice sections at the grocery store, healthfood store or home canning sections. Also wanted to get this thread back to the top.

 

[warno]

I haven't done anymore with it yet. I need to order a higher ph test kit online though. The ones I tested with are from my father in laws hot tub. I will get the other ones ordered this weekend.

 

[mike van]

warno - check your y-strainer too, if you haven't, good chance it's coating over. Mine did.

 

[warno]

I didn't install a strainer in my system or a filter of any kind actually. I'm thinking I might be doing that next year though.

 

[mike van]

The strainer might have kept the goo out of the HX, and is much easier to clean -

 

[warno]

I'm thinking about installing a filter in line for next year's project since I'm going to be basically replumbing the whole system. Hopefully this year's running doesn't clog anything up.

 

[Bob Rohr]

It's a good idea to test the water that you fill or refill with. High mineral content will coat the HX surfaces and lower the efficiency, depending on the thickness of the layer.

You might buy, or rent a DI unit to fill the system through after a good cleaning with a hydronic clean and flush product.

Sample the water and send it to a lab or company that specializes in treatment for boilers. You want to tailor the treatment or chemical use to your water condition.

Fluid quality is becoming a yuge issue in the hydronics industry. Manufacturers are tightening up warranty replacements when they see failures related to fluid quality, boilers, pumps, control devices, heat exchangers, etc.

An open system will require an on-going treatment program to assure a long and efficient lifecycle.

Here is some intro information regarding water quality.

http://www.caleffi.com/sites/default/files/coll_attach_file/idronics_18_na.pdf

 

[warno]

Going to dig this thread back up because I had a chance to open up the water jacket today and drain it down. Here's some pictures of the white scum and my anode rod. Could anyone tell me if it's from my anode or my water? The scum collected on any surface that it could "settle" on.

Heat exchanger top






Anode rod, also notice the firebox sides are white from the scum.



And now that my water jacket is drained, will it be ok until I refill again next fall?

 

[mike van]

Warno, to your last question I would say no - I believe rust will start to form [soon too] on all those surfaces unpainted inside, leaving you a bigger mess than the white scum. Not sure what the scum is, i'm planning to run mine another month before doing what you are now. I'd bet if you got a good sample of it, Precision Chem could tell though -

 

[warno]

I already drained and rinsed it all out. So a sample to send out can't happen now.

So you're saying I should refill and add treatment before any rust starts forming?