Hydronic heating system books websites etc.

The thermal shock and the Grundfos pumps is where I have seen the problems. The shaft is ceramic and the shock causes the shaft to break. Where I live the weather is such that at night we may need heat but at noon A/C. The lead and the lag on imbedded floor heat creates a problem. Geothermal heatpumps are not that expensive if you can get a "connection" for the purchase. Mine actually cost less than a conventional heatpump. Ross, if you do not fire your wood fed outdoor boiler for a week in the winter how do you keep the pumps and associated lines from freezing?

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Agmantoo
If they can do it,
you know you can!

So you're running from shut down to building heat and transferring that hot water through a cold pump? Still you're going to get that wild swing on both sides of the system I'd think. I'd move to a different pump, or a plate exchanger and run the boiler and pump constantly drawing off the exchanger when needed so your pump never goes cold! Probably cheaper to keep the boiler hot than starting and stopping. The thermal shock I was refering to was to the boiler, but that is really only a problem with a higher delta T

The oil fired boiler will use the wood boiler as a reservoir and will use the same under ground pipes etc. The oil boiler will sit beside the wood boiler outside (in a shed) The system never stops being used, except the wood combustion chamber, so no freeze up problem. I had considered 12v pumps and a solar power system but I've ample hp to spin generators and 4 portable gensets. I am looking for a tractor powered generator 20 kw is about the max I can turn at full load comfortably.

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Do not meddle in the affairs of Dragons, for you are crunchy and good with ketchup........

Then go to the "wall"
Dan Holohan is respected in the industry of hydronic heating. He has authored many books.
http://www.heatinghelp.com/library.cfm
Plus the guys at the wall are very knowledgeable. and are most always willing to answer your questions.

Thanks Eric one of my instructors mentioned Dan Holohan's books etc. Supposed to be one of the top in the field yet without an engineering degree.

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Do not meddle in the affairs of Dragons, for you are crunchy and good with ketchup........