Solartwin solar thermal controller, PV and Ecocirc Pump Get rid of mains pumping for your solar water heater! Start Price GBP 350.00 Current Price GBP 350.00 Time Left - Bid Count 0 Buy It Now Price - Reserve Price - Start Time Monday, October 06, 2008 End Time Monday, October 13, 2008 Location Chester, Cheshire See more about 'Solartwin solar thermal controller, PV and Ecocirc Pump' Description What does the Solartwin solar thermal controller package include?Laing Eco-circ Brushless DC Impeller Pump D5solar-38/700 B or equivalent normally with brass 1/2 inch male connections, manual, suitable for some pressurised and open vented solar heating systems 24 month manufacturers warranty. Not pictured.30W 12V nominal PV, crystalline, terminal connections to rear, aluminium frame, no roof mounting brackets, rectangular, exact shape may vary. 5 year Solartwin warranty.  Not pictured.Solartwin Zero Carbon Controller,  pictured above, suitable for the above pump and PV.  5 year Solartwin warranty.About the Zero Carbon Controller. This is a differential temperature controller which can be used for controlling a a variety of photovoltaic or low voltage DC solar heating systems including Solartwin. It makes your solar panel operate efficiently and safely, with very low or even zero operating carbon impact. As a user, it lets you see the water temperature near the top of your hot water cylinder. This temperature will be similar to what will come out of your taps. But behind the scenes it is doing a lot more. It controls whether the pump is on or off, using two special ways of working. These are called differential control and occasional heat export. Here is a brief explanation of each. Most of the time the controller is doing differential control. Here, it compares the temperature of the top of the solar panel with the bottom of the hot water cylinder and it switching the pump on or off accordingly. For example, when as the solar panel is a slightly hotter than the stored water in the cylinder, the controller switches the pump on. Provided there is enough solar electricity available, it then pumps send hot water from the panel into the top of the hot water cylinder so you can use it when you need to. Later, when the stored water is hotter than the solar panel, the pump normally turns, off since the panel would otherwise cool the stored water. However, when the top of the hot water cylinder does over a preset high temperature, such as 65 degrees C, heat export control takes over in order to  reduce the risk of scalding. Here, the pump keeps on pumping until the water at the top of the cylinder falls below the preset temperature. Then it reverts back to differential control. In a clever innovation the Solarwin Zero Carbon Controller does not require mains power, because its electricity comes from a solar electric (photovoltaic) panel. Place a Bid!