Hard water to Soft


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Old 10-26-13, 09:41 PM
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Cool Hard water to Soft

If you run a boiler on hard water for 2 years, then flush and fill it with soft water, will the new soft water eventually remove the scale that must have built up in the boiler????

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Old 10-27-13, 12:28 AM
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Doubtful. However, only STEAM boilers are susceptible to scale build up unless the hot water heating system leaks severely.
 
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Old 10-27-13, 06:24 AM
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My 60-year-old hot water heating system shows no evidence of scale or corrosion when I have opened up the system for maintenance.
 
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Old 10-27-13, 07:51 AM
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Cool

OK, good to know. I though hard water wasn't good for Brazed Plate exchangers???

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Old 10-27-13, 08:00 AM
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I though hard water wasn't good for Brazed Plate exchangers???
It is not, but that isn't what you asked!

The point that Furd made is that 'lime scale' (it's just called that, it's calcium and magnesium) is only a problem when water is constantly being added to a system.

The amount of 'hardness' in a single filling of a boiler is not enough to cause a problem. It's the constant supply of fresh water entering a system that causes a buildup over time.

If your system is leak free, you only fill it once...

Still, with the tiny passages in a HX, they do occasionally need to be acid flushed. And the buildup may not be on the 'boiler' side...

Where is this HX in your system? Connected to what?
 
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Old 10-27-13, 10:51 AM
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Question

It's mounted directly on the top of a 55 gal Versa Flame boiler.

Which brings up another problem. It runs hot all day, despite no actual use of hot water due to thermal syphoning. If I close one of the shutoff valves (there are two), it cools down, and, remains cool till I open the valve, and, use some hot water.

It drains enough heat out of the boiler when not being used, to cause the boiler to fire at least twice during the day, on top of the boilers normal firing rate.

You would think a company as advance as HTP would have built anti syphoning into the DHW system.

Any easy fix for this. It's a pain in the butt turning the valve off and on all the time when I want hot water.
 
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Old 10-27-13, 12:46 PM
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You would think a company as advance as HTP would have built anti syphoning into the DHW system.
Can't put all (if any) of the blame on HTP really... because the installer should have known better and heat trapped it himself.

In the end, while it's easy enough to say that they should have designed their products so that they were "installer-proof", bottom line is that any install is only as good as the installer!

Any easy fix for this.
I don't know... I'm still not sure what you're working with there.
 
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Old 10-27-13, 06:33 PM
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I did the install myself.

The HX came factory installed and, pre plumbed on the boiler.

I'll try and take a couple of pics tomorrow.

Here's what it is

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Old 10-27-13, 08:03 PM
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On the question about the HX, after looking at that manual, and reading the manufacturers warnings about water quality and chemistry, and seeing that your hard domestic water flows through one side of the HX, I would say there's a good chance that the HX is at least starting to scale up.
 
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Old 10-27-13, 08:17 PM
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Yeah, that was a concern. Would running soft water through it from now on help clean out the Domestic side of it????

I'll prolly take it off next summer and soak it in vinegar for a day.

Would still like to remedy the syphoning. There's not much room pipework wise to install a check valve. I might have to make, or, modify something to fit in an existing piece of pipe.

I notice the new Taco Bumble Bee has a built in check valve. If they sell that separately as a part, I might be able to retro it into the existing Circulator.

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Old 10-28-13, 12:31 AM
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Would running soft water through it from now on help clean out the Domestic side of it????
Same answer as before, no. I doubt that vinegar would be strong enough to do any good unless you can find some of the 20% stuff sometimes used for weed control. CLR might work but absolutely no guarantees. Best to rig a pump with a bucket and circulate the acid through the exchanger while periodically testing the strength of the acid. Keep adding acid to maintain a specific strength until it is no longer being neutralized by the scale dissolving into solution and then rinse thoroughly. Look into the acids used to clean instantaneous (tankless) water heaters.
 
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Old 10-28-13, 07:25 AM
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Cool

Household vinegar works fine on my shower head, and, toilets.

About every three months I get a pretty hard coating (stiff brush won't touch it) of greyish calcium buildup in the toilet bowl. One cup of vinegar overnite softens it up, and, very light brushing, scrubs it up nice n clean.

Is the stuff in the Brazed Plate going to be any harder than the toilet/shower head buildup, maybe because of the heat involved.

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Old 10-28-13, 01:36 PM
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I don't know. You can certainly try the vinegar as it won't hurt anything but in my experience it takes a bit stronger acid than normal household vinegar.
 
 

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