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12v dc pump activation

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Hi all

Our evac 15 tube solar collector has been working well for years(not so good in winter), but I have the problem in the sense that the 12v dc pump connected to small 12v solar panel keeps on circulating until late afternoon(or while partly cloudy) when there is not enough sun to heat up the tubes, but enough sun to keep the pump going. I am worried that I may loose some of the heat accumulated during the day due to losses, although pipes are insulated.

What would be the best way to stop the pump when sun is not sufficient to heat the tubes?

Install thermostat/thermal switch in the manifold to control the pump?

I have a retrofit geyser, i.e. tubes on roof, geyser downstairs.

1 hour ago, Beugleuce said:

Install thermostat/thermal switch in the manifold to control the pump?

Ideally you would want to take temperature readings in the manifold and compare them to the temperature in the HWC (hot water cylinder), if the manifold temperature, is more than, say 4 degrees Celcius higher, then you'd want to run the pump, if its is 4 degC or less, you probably shouldn't...

Edited by Kalahari Meerkat

3 hours ago, Beugleuce said:

Hi all

Our evac 15 tube solar collector has been working well for years(not so good in winter), but I have the problem in the sense that the 12v dc pump connected to small 12v solar panel keeps on circulating until late afternoon(or while partly cloudy) when there is not enough sun to heat up the tubes, but enough sun to keep the pump going. I am worried that I may loose some of the heat accumulated during the day due to losses, although pipes are insulated.

What would be the best way to stop the pump when sun is not sufficient to heat the tubes?

Install thermostat/thermal switch in the manifold to control the pump?

I have a retrofit geyser, i.e. tubes on roof, geyser downstairs.

Was your's installed without a Geyserwise control, as that manages the exact issue that you are now experiencing. It activates the pump conditionally, i.e. you set it to a differential temp trigger. Once that set value is reached, the pump starts until the temps are equal again.

6 hours ago, Kalahari Meerkat said:

Ideally you would want to take temperature readings in the manifold

You could install a Sonoff temperature controller and set it both on time and temperature to cover most hot water generation.

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