Filling hydronic systems with demineralized water?

Reply

  #1  
Old 07-29-16, 05:45 PM
Member
Thread Starter
Join Date: Oct 2008
Location: USA
Posts: 2,881
Received 5 Votes on 5 Posts
Filling hydronic systems with demineralized water?

John Siegenthaler, a noted expert on hydronic heating, has a monthly column in PME magazine. The July 2016 edition has a special report, with an article by Siegenthaler, "Water Quality Matters." He recommends that demineralized water be used in hydronic systems. For smaller systems, fill them with demin water. For larger systems, he recommends an ion-exchange column as a side-stream device with continuous flow provided by the circulator pump.

Wow, this comes as a surprise to me. My 65-year-old, steel, fire-tube, residential, hot water boiler has always used plain city water. Filling it with demin water wouldn't be too convenient every time it is drained for maintenance. A side-stream, resin-type ion exchanger would be a bit complicated considering the need to regenerate the resin.

I've reread the article, thinking perhaps I misunderstood, but I don't think so.
 
Sponsored Links
  #2  
Old 07-29-16, 06:45 PM
lawrosa's Avatar
Super Moderator
Join Date: Dec 2010
Location: Galivants Ferry SC USA
Posts: 17,804
Received 10 Votes on 8 Posts
Whats your point? My boiler is some 50 yrs old and on well water...

Johns a good guy but show me the yrs and yrs of water tests on boilers and their longevity....

Aint none probably as all water and boilers per location are different IMO...


Im sure joel will chime in...


Your post is open ended really....
 
  #3  
Old 08-01-16, 07:18 AM
Member
Join Date: Nov 2007
Location: MI
Posts: 2,612
Received 0 Votes on 0 Posts
Isn't there a pill for that?
Kidding aside, in the automotive sector there are additives in the oil that help with ph, carbon, dirt, etc. In the cooling system there are additives to the glycol that do much the same, plus help keep galvanic corrosion at bay in engines comprised of steel, brass and aluminum parts.

Why do we use untreated tap water in home heating?

AFAIK my 40 year old cottage system has the original glycol in it. Previous owner claimed it has never been serviced.
 
  #4  
Old 08-01-16, 10:08 AM
Member
Join Date: Mar 2006
Location: Wet side of Washington state.
Posts: 18,485
Received 28 Votes on 22 Posts
The worst thing for water in a closed loop system such as a hydronic heating system is oxygen. Keep the oxygen out and you can forget about it.

Unfortunately, that is far easier said than done. Leaks are the primary source of oxygen because the "make up" water is usually saturated with oxygen in solution. Eliminating the leaks and eliminating the make up water is the ideal.

There are several chemical treatments available to control both scaling and corrosion. They are rarely used in residential systems because most are toxic to human health requiring backflow prevention devices on the make up water system. These backflow devices are more complex than the usual Watts 9-D device and often require annual testing and certification...at a cost. Further, few homeowners are diligent in testing the chemical concentrations of the system which often leads to lower chemical levels and as false sense of security that the piping is being protected.

For most residential systems there is no need for using anything other than potable (drinking quality) water.
 
  #5  
Old 08-01-16, 03:38 PM
Member
Thread Starter
Join Date: Oct 2008
Location: USA
Posts: 2,881
Received 5 Votes on 5 Posts
My 65-year-old hydronic system is piped with black steel pipe. When I open or cut into the piping for modifications (such as replacing valves, adding a low-water cutoff, etc.), the inside wall of the pipe is completely free of scale or corrosion.

I have a conventional expansion tank with B&G Airtrol fittings that continually remove any air from the circulating water, and return it to the tank. Leakage is essentially zero - during the summer, I isolate the connection to the automatic fill valve from the city water supply, and the system pressure does not decline at all. There have never been any additives used with the water.
 
Reply

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread
Display Modes
 
Ask a Question
Question Title:
Description:
Your question will be posted in: