Diddy water pump?

Probably not continuously rated. Another like this would be a windscreen washer pump.

For this application, I would look at a small aquarium pump. They are pretty much silent but must be kept under water all the time.

They probably need too much energy anyway for a solar cell and unfortunately are AC motors as well, normally. A small pond pump would do the same job. To reduce the flow rate, you can simply add a tee with a small plastic valve (also from aquatic shops) to effectively bleed some of the water back to the reservoir.

.andy

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I've seen this in one of those garden catalogues complete with the solar cell for about £25. But of course I've thrown the catalogue away :-(

A solar fountain would probably work. You just run a pipe from the output to the top.

We had a solar powered one to pump a trickle from our pond into our pond, it worked a treat until the filter was blocked and we never bothered making it right again. Sorry, though, can't remember where we got it. Somewhere in Leamington Spa.

They must still be made though.

Mary

Suitable pumps are made by whale, used by boaters to circulate freshwater.

See item "E" in red on this page:

That looks just about perfect, Steve, though I'll have a look round for pond kits too.

Si

You may need to fit some sort of flow restrictor to get the flow down to a trickle. The easy way is just to clamp the outlet hose - when I designed laboratory rigs we just used a length of silicone hose with a screw tubing clamp to regulate the flow from small pumps.

Car windscreen wahser pump. There are model boat pumps, mainly for cooling electric motors in racing boats.

Dave

those are rated for something like 10 seconds duty. Will be charcoal in under a minute.

Regards, NT

In message , N. Thornton writes

I(f you can find someone chucking a Vaillant 242E boiler out, there's a natty little pump in the back of the electronic control box which would do the job - continuous running and 24vAC

birdbath/water

You could ask the folks who make that solar water heating system which has a PV panel driving a small DC pump if you can buy the pump separately. Prolly a bit expensive given the cost of the entire system. Sorry can't think of the name of the system but if you google solar water you ought to find it.

What's that used for on the boiler, Geoff?

.andy

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Modulating the gas pressure believe it or not

Meaning gas goes through it? Surely not.

Or is it pumping water to operate some kind of diaphragm valve or something? I'm intrigued. How does it work?

.andy

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Me too, nobody I've asked actually knows exactly. As far as I'm concerned (workwise) it's just a load.

It definitely pumps air to a diaphragm valve, but it does seem a peculiar way of doing it.

Now that things are slowing down a bit I will do my best to find out