Pre-tankless filtration/ water treatment?

rbphhc

Property manager/ contractor here.

Recent install of an RU199 propane tankless in VT. Original order was supposed to include a Rinnai Scale Cutter, but supplier was out of stock, and this item fell through the cracks. Need some kind of filtration now to protect the HWH.

Water has not been tested yet, but clearly rust is a primary contaminant. Torrential summer rains up here in VT overwhelmed wellhead, and potable water started tasting/ looking metallic.

Investigating through view port in indirect tank showed fine rust deposits on stainless coil (see photo). Mild vinegar flush and a little elbow grease/ hose spray cleaned up the indirect well enough, but concerned about higher heat within tankless heat exchanger.

Shockingly, house has NO whole-house filter. Just learned this yesterday. Previous service provider removed existing softening/ filtration system. No idea why.

Questions:

1. I know, get water tested.

2. I know, put in a whole-house system, stat. At least a 2-stage spin down + micron (correct)?

3. How does the Scale Cutter work? They say it's *not* standard polyphosphate crystals. Is it a resin system? Is Scale Cutter ideal, no matter what water contaminants are? What are alternatives to Scale Cutter?

4. Magnetic systems seem interesting. Surely they'd collect iron. Some claim to alter the structure of salts, preventing crystallization. Is that for real?

5. Assuming we've got iron plus hardness of some kind, what would be effective, both for whole house AND to protect the tankless? Two separate systems probably better, correct?

PS
I'm assuming there's something better than vinegar to clean fine particulate iron oxide. It comes easily with a towel or brush. Gentle pressure wash? But this wouldn't work inside tankless HWH. Suggestions?

Thanks!

Jamie Hall

You missed a step. A very important one. Step 0. Inspect the well and repair/replace as needed. Yes, I know there has been a lot of excess water in Vermont. I've seen the results myself. That, however, is no excuse for the water quality to be poor. A brief problem, yes, if the well head was actually flooded at some point (in which case, shock chlorinate the well and pump the dickens out of it until the water clears), but lingering quality problems point to problems with the well itself.

Then having done that...

Step 1. Yes, obvious
Step 2. If the results of step 1 show excessively hard water, a water softener -- but NOT on the feed to a hydronic or steam boiler. If the step 1 shows high iron, an iron removal filter. Which is not a water softener, not yet a filter. Now if step 1 shows high suspended solids or turbidity -- not dissolved solids, but muddy/sandy water, go back to step 0. Whole house filters do exist, but are a bandaid for a poorly constructed or damaged well.
Step 3. It does not seem to be possible to get useful information on what, exactly, the Scale Cutter actually does, for which reason alone I wouldn't use it.
Step 4. Magnetic systems... will collect iron, but only if it is in a magnetic form -- such as magnetite. They do exactly nothing to dissolved iron. Nor can they alter the ultimate crystal structure of dissolved materials that are in the water flowing by.. Save your money.
Step 5. See step 2. Softening and iron removal (or manganese) are quite separate treatments, and best served by dedicated units.

rbphhc

Jamie Hall said:

You missed a step. A very important one. Step 0. Inspect the well and repair/replace as needed. Yes, I know there has been a lot of excess water in Vermont. I've seen the results myself. That, however, is no excuse for the water quality to be poor. A brief problem, yes, if the well head was actually flooded at some point (in which case, shock chlorinate the well and pump the dickens out of it until the water clears), but lingering quality problems point to problems with the well itself.

Thanks Jamie. Good point. I will have to call in a guy. Pretty sure this was a 'hippie special,' dug in the 70s. The septic tanks certainly are, sitting on top of ledge under maybe 6" of soil.

That said, I do think the well head was briefly overwhelmed. Not much color or sediment in recent weeks. The iron powder deposits on the indirect coil are likely from the flood days of July.

Water tests coming soon. Other local tests (public info) show zero serious contaminants, one case of copper, one case of manganese. I bet the latter is us. We are up a mountain in a very rural area.

I spoke to Scale Cutter. Their system is just a softener, with a proprietary blend of polyphosphates. I suspect their recipe may have been 'hacked' by China, because a bunch of cheap spin down filters are showing up with 'Siliphos' polyphosphate crystals you put in the screen cylinder. Some outfits are claiming that blend is appropriate softening for tankless HWHs.

Sure does look like removing iron is its own separate deal. Some claim a spin down will remove manganese. True? What would you recommend?

Thanks!

Jamie Hall

Oh dear. When I was one of the two sanitary inspectors for Vermont (the whole state -- what a different world1) back in the '70s I saw a good many of those "hippie specials". If it's cleared up now, you may be OK -- but I'd seriously consider improving matters... At least make sure the casing is reasonably sound and extend the well a couple of feet at least above ground level.

Manganese is also a dissolved metal problem, like iron. A spin on filter won't touch it, but there are well established exchange or resin type units which will do it, if it isn't excessive. Some will do both iron and manganese in one go.

hot_rod

If you have high iron content it will plug a softener quickly. You need an iron filter before the softener. The softener will remove scaling minerals.

I had an Iron Curtain on my last well. Then a softener. Then carbon filters at the kitchen and lav sinks for taste and odor.
https://www.hellenbrand.com/product/commercial/filtration-systems/iron-curtain

It really depends on how much iron. Some green sand softeners will work on low level iron.

The bubbles show how an ion exchange softener remover the scaling minerals.

The water test is key to what devices you want to look into to "fix" your water.
Without that it can be an expensive guess.