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Hi I am hoping someone might have come up against my problem of old "Solahart" hot water panels becoming dirty on the inside of the glass. My 12 year old 300 litre solar hot water system does not fair too well over the cooler months with the tank temperature having trouble reaching 50 degress celcius, with no daytime use. We live in Mount Isa Queensland with good sun on the panels from 9:30am until after 4pm. Upon inspection you cannot see through what looks like frosted glass. The vent holes are open and there is no condensation. There appears to be a residue over large areas on the inside of the glass parallel to the centre of the plates. Does anyone know if you can drill the retaining rivets on the edging and remove the glass for cleaning. I was also thinking of cleaning down the collector plates and painting then flat black, rather than their greyish colour they appear to be. Surely someone has come up against this problem, as I have read plenty of issues about corrosion, the only thing I fortunately do not have. Hopefully this will return some efficiency to the old system and stop it becoming an an electric heater so much.
Yes you can remove the glass without breaking it. You will need to take the panels down. Remove the angle retainer carefully (do everything carefully). To remove the glass carefully slice thru the foam rubber seal with a thin disposable blade type knife, the narrow blade ones are best. Be patient dont rush it. When the glass is fully separated find a helper and lift it off. Place glass on edge on cardboard up against a wall. Don't leave the glass there without driving in a wooden stake to prevent it falling or overnight a wind gust will be sent by Mr Murphy and it will be smashed. It is not worth buying new glass for an old panel. I should also say make sure they are copper tube panels as the steel collector type are not worth fixing either.
Once the glass is removed clean off all the old sealing rubber, a tedious job. gentle cleaning of the collector may restore its 'blackness' remember it is a 'selective surface' so needs to be pretty bad to be improved by painting it with paint. I guess if you had to 'stove black' would be best. Check if the collector has been leaking at any of the welds, corrosion will indicate this. Take it out clean up and reweld. If the insulation has collapsed replace it but don't just squash in thicker insulation, it wont work as well. The best way to reseal the glass is not silicon. It will work for a while. What you need is the original rubber foam seal which comes in a roll with a sticky peel off backing. It is not cheap, I am told by someone who fixes dozens of them. I need to take 2 of mine down and fix them again after 5 years, yes I tried the cheap method, silicon, and now when it rains water gets in.
If you want your flat plate HWS to get hotter, minimise the losses, by insulating all the hot bits up there, even the valves. Those exposed copper pipes and brass bits suck out heat in cold weather. I extended the 'no supplementary heating' period by 2 months by extra insulation. The tank (in roof) looks like a polar bear.
Posted Tuesday 16 Aug 2011 @ 1:43:04 pm from IP
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