-=> Quoting Alec Cameron to Bob Knowles <=-
 AC> On (30 Apr 96) Bob Knowles wrote to Jock Rogan...
 
 -=> Quoting Jock Rogan to Alec Cameron <=-
 
 BK> In this case they think the guy looking after it might have dozed off to
 BK> sleep, and there was a larger than usual demand for steam, the water
 BK> level dropped and BANG!!
 AC> As a youngish chairborn engineer I had to operate a boiler feed pump
 AC> during an Operators' strike at Bunnerong NSW. The stress, physical and
 AC> mental was so severe,that after arriving home [driven] my wife had
 AC> almost carry me into the house. The adjacent boiler did go bang!
 AC> [wasn't my problem!] and it is a a cute sight to see a 200 ft high
 AC> rectangular boiler, changed into barrel shape!!
Yes steam, as fire seems a very good servant but a terrible master!!
I looked into the boiler that blew up in Adelaide and the water tubes
were like pretzels in part of the boiler, twisted everyway which!!
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 AC> No... not really a HOMEPOWER project. Best application, should be the
 AC> fairly traditional unpressurised hot water fed central heating system,
 AC> convection circulated. With water thermostats in each room, the auto
 AC> control works great. 
I have always fancied hot water pipe under floor heating with
thermosyphon but I have a hot water boiler with a small pump that uses
so little power that I leave it on all winter without switching it on
demand. I use my fan coil air conditioning system to heat the house, I
use chilled water in summer for cooling on a two pipe system, with
afterthought a 4 pipe system may have had some advantage, but there is
always the extra cost of extra pipes and coils. As it is, I have
electric elements for reheat in the summer months. The elements are not
used much.
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For anyone who does not understand 2 and 4 pipe systems, 2 pipe is a
flow and return that uses hot water in winter and chilled water in
summer. The same coils are used for both applications (heating and
cooling) The 4 pipe systen has 2 flows and 2 returns. A flow and return
for the hot water and a flow and return for the chilled water. The 4
pipe system need a heating and a cooling pump. It also needs a  heating
and a cooling coil  in each fan coil unit.
In the 2 pipe system valves are use to change the flow of water to
either the chiller or boiler as needed.
With a pumped system you can use much smaller pipes and the chance of air
lock as found in a thermosyphon system are almost eliminated.
In Thermosyphon special care must be used in the design to make sure that
all air can escape from the pipework to prevent air locks.
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 AC> Hey, is this echo being hi jacked by Aussies??  Cheers...ALEC
                                       
 AC> ... ........My heart is in the Highlands
Yes and you can use a little heating in your neck of the woods at this
time of the year. Not sure if we are hi-jacking but we are certainly
putting in our tuppence worth :-)
Bob.
... Catch the Blue Wave!  
--- Blue Wave v2.12
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