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Because the system may not freeze in winter time, I had to build a heat exchanger. The outside system is filled up with antifreze. I decided to place 6 copper spirals in the solar boiler. The spirals had to be placed one by one by turning them in the small hand hole.

Copper tube of 10 mm outside.

A little bid bend work. Winding the copper tube up on a plastiek drain pipe of 10 cm

6 spirals with a total passage surface of 3 cm2

Total lenght is 50 m tube of 10 mm witch is 1.57 m2 contact area.In totaal 50 m

The 6 in- and out's must be connected with in the small collector. Here not yet welded.

I put 6 pieces pipe (12/10 mm outside/inside diameter) in the collector, in those 6 pipes comes the 6 inlet of the spirals (10/8 mm outside/inside). So afterwards I can easely soldering the spirals ends (placed in the solar boiler) in the collector.

Two collectors: in- en outlet

To be sure there are no leaks, I soldered the ends to do a pressure test 3.5 bar. Later I wil cut the ends again.

Placing the spirals....

one by one

All 6 in the solar boiler. Now putting the in- and outlet togehter.

Woow, ... how are we gone do this ...

Two copper laths with 6 holes in it on the same distance as the collector will hold the 6 tubes.

Then the collectors can be mounted and soldered.

All 12 tubes soldered on the collector pipes wiht tin solder

In- and outlet of the collectors will be connected in this fitting, mounted in the solar boiler.

Inside view in the solar boiler of the 6 spirals and 2 collectors.

Sunday 21/05/2006 filled up the solar boiler with water to the top. A final pressure test of 6 bar on the heat exchanger with colletors and ....... A LEAK @ $`£ &§.......!!!!! Probably by manipulation of the collector, I don't know. I had to disconnect the 2 collectors from the solar boiler and pull them out again to repar the leak. Problem is now that the collector is soldered with tin solder on the tubes, so temperture can't go to high on this soldering. A wet towel on the collector while welding was the solution!