On 7/25/2017 5:23 PM, James Wilkinson Sword wrote:
On Tue, 25 Jul 2017 22:17:48 +0100, Ed Pawlowski wrote:

On 7/25/2017 3:47 PM, TimR wrote:
On Tuesday, July 25, 2017 at 7:40:39 AM UTC-4, Ed Pawlowski wrote:
Water sits in the hot water tank and the minerals collect over
time. In
your case, they were circulated more than normal. Water heaters are
notorius for mineral buildup.

I don't know the exact chemistry of it but if you get hot water too
hot, minerals precipitate out. We've had that problem with boilers
at work. If we set the temperature too high, or it got out of
control, mixing valves etc would start failing in a day. I would
think that temperature is hotter than domestic hot water tanks but
maybe there's some effect at a lower temperature.



Your boilers at work should be blown down on a regular basis and
possibly have chemical treatment. I used to do a test every day on our
steam boilers as we used a lot of water. Even though softened you still
have to be careful with steam boilers. We operated at 110 psi, over 300
degrees.

Why don't cars suffer from this? Can't we make boilers run like car
cooling systems?


Sure, depends on the system. Steam used for process is constantly
adding make up water. We used 250 to 400 gallons an hour depending on
production load. These were 125 hp boilers running high pressure and we
had to have a state licensed person on staff any time they were running.

Boilers in industrial setups have plenty of places for loss in the
system too if you have many meters of piping. Smaller residential
boilers usually don't see those problems.

In another section of the building we had a steam heating boiler and it
needed very little care and no chemicals. Makeup water was minimal and
it was low pressure (15 psi) so no license needed.