So, solar water heating, eh?

At last the solar heating system is up and working.



When I filled the system (initially with water) there was a substantial leak at the bottom right hand corner. I'd forgotten to tighten a compression joint. And a small leak (which I found later when the system pressurised) at the top where another compression fitting needed a bit more brute force. Otherwise totally uneventful.

Filling with antifreeze took a while. I didn't want to try pumping in 40 litres of fluid - too much like hard work. Luckily the tops of the panels are just a little lower than the ceiling in the boiler room, so I rigged up a large bucket and hose into the pump station, and balanced it on a stepladder on top of the boiler. Gravity did the rest, slowly it's true. I opened a valve at the bottom in the "return" pipe in the garden shed to allow the antifreeze to push out the water in the pipes: when the water started coming out pink I closed the valve. The panels then filled and started pushing the water in the "flow" pipe back up to boiler room. Eventually - much more slowly as it's uphill - the water coming out the end of the drain on the pump station gave way to antifreeze, and Voila! - filled. I then pressurised the system using a garden sprayer pump and a bit more antifreeze. The pressure went up and down a bit, I suspect as air gradually vented through the (three) automatic valves.

But then I was able to plug in the controller and to my surprise it all started working. Good and hot too. For the first time we have a hot cylinder completely full with hot water - the boiler can only heat the top third of it.

As it's good sunny weather I've told the boiler to stop trying to heat the water. It's still doing the radiators....

Getting warmer

After quite a long time working on the solar heating, I finally got the panels mounted on the roof of the garden shed, and connected up to the pipework. It took all day, and the sun was just starting to set when I took the picture:



It had been a sunny day and the copper pipes at the top of the panels got too hot to touch, even with the white plastic film reflecting most of the heat. The small amount of steam that came out suggested that the manufacturer had tested them with water for leaks. A couple of the the connector pipes were damaged in transit (thanks, TNT) and I am concerned that they will leak tomorrow when I finally fill the system up and get it under pressure. I can only hope that a thick winding of PTFE tape will block the gaps.

The temperature sensor isn't yet in place, so I'll have something to do (splicing and soldering) while the system is filling up. The first fill will just be water as I am not sure whether I have enough of the special anti-freeze to be able to waste a litre or two. I think I have worked out a way to flush the water out when the antifreeze finally goes in. But we'll see.