12 VOLT WATER PUMP
This pump was purchased from Charles Austen via EBAY at a cost of £136.00. Six weeks delivery time. There is a more expensive brush-less version available for an extra £100.00 that would have a longer life, but as there is likely to be a lot of developments in this area in the next few years I think this one will do for now. In some early experiments using an old central heating radiator painted black I tried an Audi headlight washer pump from EBAY and a few windscreen washer pumps £10 a time from car spares shops. The Audi pump used too much current and pumped too fast and was awkward to connect to, But looked like it would last for ever. The 1st two windscreen washer pumps only lasted a couple of weeks, but pumped about the right amount. The third pump has been going for a few months and is still going, but I would not expect it to last much longer. The Charles Austen pump is quite noisy, sounds like a woodpecker in the loft. It needs to be suspended in some way using plastic cable ties and insulation, depending on your setup. Also make sure that all your pipe connections are secure as this pump can build up quite a pressure if the flow pipe is blocked or restricted. The pump must be about 150mm to 300mm above the water level in the loft expansion tank. The DL2 pump from Charles Austen appears to be no longer available unfortunately. Although they are still doing a 24 volt and 240 volt ac version. Some people have suggested to me that they ( C/A ) have stopped selling the 12volt pump to the DIY community after pressure from a big customer in the solar hot water trade. An alternative pump worth looking at would be the SID 3.5PV manufactured by IVAN LABS, INC of Florida. I have seen this pump on EBAY from a seller ( mavericksolar ) . 18-08-10 Decided to buy a pump on EBAY from Thailand. Total cost including postage £26.44. May get some customs charge when it arrives. Just have to be patient now. New pump ( Pump NO 2 ) arrives on the 28-09-10.
Pump NO 2
Just got to figure out how to plumb it in. There were no customs charges so the total cost is £26.44 with 10 days delivery. First impressions are that this pump is quite heavy, this I like, and is very quiet when running. Specifications are quite impressive also. Brush less motor life 40000 hours. Can be run continuous. Very quiet operation. Have to make sure its connected the correct polarity, and must not run it with no water. The height the water will pump is much lower than the ( C/A ) pump, but this should not be a problem as the same amount of water is rising and falling. We are only moving the water around the system not lifting it. Went to a local plumbers this afternoon and got the fittings to make two 1/2 bsp to 8mm reducers, and fitted these to the new pump. Installed the new pump this evening. May have some priming problems tomorrow as the new pump is not a positive displacement type, and I may have got air in the system fitting it. Must say I have become quite fond of the old ( C/A ) pump, clattering away in the loft. It looks a sturdy job. This will give me a chance to dismantle it and look for signs of wear and tear. Also interested to see if there is any lime scale build up, as we live in a hard water area, and it has been running for two years. Will look at the brushes also. 01-09-10 The new pump. The panel got quite cold in the night and the controller shut down, but by 8.30 AM the panel had started to warm up ( looks like its going to be a sunny day ). New pump started pumping dead on 9 AM. As I feared it was just pumping air. This is a problem with non positive displacement pumps. Needs to be primed. Decided to pull off the pipe going in to the top of the tank, after closing the isolating valve, and suck the water through to prime the pump. Took some doing. had to suck water up from the bottom tank connector, through the new pump, then the panel, and down to the top of the tank. Then I put the end of the tube into a bucket to make sure the pump was now pumping. And it was with the water coming into the bucket really quite hot, and its only 9.30 AM. You can't suck the water all this way in one go, so have to put your finger over the end of the pipe as you have a breather. This stops the water dropping back. 11 AM just had a good look at the pump. No leaks and the motor is not at all hot. I think its pumping about the same as the ( C/A ) pump ) this is handy. It's a quiet as a mouse, and it knocks about £100.00 off the cost of a system. Problems Started about 1 PM. Noticed that the hot return going into the top of the cylinder was not hot, and that the pump kept getting air locks. Also the panel temp was off the scale. Tried all ways to stop the airlocks but to no avail. The ( C/A ) pump was above the water level in the cold water tank and worked OK. So I thought this could be the problem, and put the new pump on the loft floor below the water level in the tank, but this made no difference. May be that my panel offers too much resistance for this pump. It's pumping into the bottom of the panel but not coming out of the top. Gave up about 4 PM and put the old pump back, and things were as normal. Clatter away old friend. Last night I took the ( C/A ) pump to pieces for inspection. Really impressed with its construction. Stainless steel valves, and ball bearings. No sign of any limescale build up, and brushes OK for now. Need to get hold of a second hand DL2 pump if I can.
29-10-10 another new pump
I will call this pump: Pump NO 3. Purchased as new from Ebay for £20.00 including postage. There are 6 versions of this pump. FL-2201 to FL-2202A all 12 volt, but slightly different powers. This one may be just a bit too powerful, but we will see. I am testing it at the moment, and first impressions are that is ideal for our needs, But I thought this about pump NO 2 and that turned out no use at all. Some things I like about this pump are. Very low cost. Positive displacement, Can draw water up from a bucket over 4 feet. So no problems priming, and can pump at quite high pressure, should work with any panel, and long pipe run. The C/A pump ( Pump NO 1 ) as worked a treat for 2 and a bit years, But I have no way of knowing if it is pumping the optimum amount of water per hour. With this pump drawing slightly more current there could be an issue with the battery running down. I have this pump set up with my controller, pumping in an out of a bucket at the moment, and if all goes well I will plumb it in to my system on monday morning ( 1-11-10 ) before the sun gets up. The silicone tube I am using fits really snugly on to the pump outlets. Like pumps NO 1 and 2 this pump can't be allowed to freeze as it will surely split open.
1-11-10 --12.00 AM Fitted new pump: Pump NO 3. New pump fitted OK just before the sun came out. Started pumping at 12.30 AM. Quieter than pump NO 1 partly due rubber mounting feet. Just have to keep an eye on the battery voltage for a while. Had no problems with priming or airlocks so far. 5-11-10 Not had much sun yet, but so far so good. Battery not draining very much when the pump is running. Just think that this pump may pump a bit too much water. Will have to wait for a sunny day. 6-11-10 Noise level from pump NO 3 is about the same as pump NO 1. Pump NO 3 just makes a lower sound. Pump NO 3 pumps about twice as much water per minute as pump NO 1, so I have set the contoller off delay to 15 seconds. This makes about 30 seconds total off delay. If this works out OK I will buy another one of these pumps as a spare.
30-03-11 Latest on pumps. Positive vs non positive displacement pumps. Pump NO 1 ( Charles Austen DL2 ) and pump NO 3 ( Propumps FL2203-1 ) both work really well in my system. A few people are having problems ( as I did ) using the non positive displacement ( NPD ) pumps such as pump NO 2 above, the EL CID pump and the laing pump. So I would not recomend using these pumps in this type of system. A low resistance non return valve somewhere in the loop may cure these problems, but I am not sure about this at the moment. I would like to try a Propumps FL 2201 pump, but have no idea where to get one. This pump pumps a bit less.
20-03-11 Pump NO 3 has been working a treat for about a year now. There are 2 people selling these on EBAY at the moment. I bought 2 for less than £50 so I have a spare. No need to bother trying to get the British made pump. Considering importing some of pump NO 3 from China myself.
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