[Greenbuilding] Controlling FLoor Heat

[Speireag Alden]

On 2008, Jan 24, at 14:50, Lawrence Lile wrote:

> My take, after combining the domestic and floor heat (another stupid
> mistake) is definitely separate them.  If they are combined, you  
> end up
> with an "open" system.  This is OK, but if you hook a solar loop  
> into an
> open system, you mostly get solar heat poured into the floor and very
> little in your DHW.  Go with a "closed" system on the floor heat side.

     I think that this is more an artifact of your lack of insulation  
under the floor, rather than an essential characteristic of an open  
system.  If I had a solar system hooked onto my system, I would think  
that the heat would go wherever the system told it to go, and if I  
put it into the floor, it would warm the house.  Otherwise, it would  
warm the contents of the heater.  If I plumbed it properly, the  
entire system would flush when I ran a hot water tap (and this is  
essential for health safety).

> Another issue is oxygen.  Some boilers and heating equipment can't
> handle oxygen in the water, and if your DHW and floor heat are  
> combined,
> you've got oxygen in the water permanently.

     This is a good point.  For my open system, I had to use a bronze  
circulating pump, for instance.

-Speireag.