Navitron Renewable Energy and Sustainability Forum

General Renewable Topics => General Discussion => Topic started by: clifden on April 24, 2019, 11:38:25 AM

Title: solar thermal how to connect to system
Post by: clifden on April 24, 2019, 11:38:25 AM
Morning .
recently installed a three heat source system connecting to a thermal store .
a wood burner with back boiler . - no control as such just stove is lit or stove isn't
Oil fired boiler - thermostat on thermal store to call for the boiler to fire if the temperature of the store goes below a set point .

solar thermal panel 30 vac tubes .  I had an electrician install the controller  circulation pump . my understanding is there is a probe in the thermal panel which controls  the water flowing to the heat exchanger . so in my terms if the panel reaches a certain heat the probe sends a signal to the controller which activates the pump that circulates water via the coil in the thermal store which heats up the water in the thermal store and removes the heat from the panel .
the electrician wants to fit a thermostat to the thermal store to control the circulation pump .
I have talked it over with him a few times but he is adamant that the thermal store requires this thermostat.
does anyone have a diagram of the advised method of setting up a thermal panel with the associated heat exchanger /circulation pump .
or can point me in the right direction.

Title: Re: solar thermal how to connect to system
Post by: andrewellis on April 24, 2019, 11:57:51 AM
You would certainly need one in the thermal store to turn off the pump if the store is too hot.  Maybe that is what he is referring to.  If you used the thermal store to to determine when to run the pump to the panels you would end up sending all the heat into your local county if it was colder outside than the store

Title: Re: solar thermal how to connect to system
Post by: rogeriko on April 24, 2019, 08:32:18 PM
Solar Thermal controllers are differential controllers so they need a thermostat in the store to turn on the pump when the panels are hotter than the store, and to turn off the pump when the panels are the same or less than the store.

Title: Re: solar thermal how to connect to system
Post by: ecogeorge on April 24, 2019, 08:37:59 PM
Try googling something like -thermal store pipe schematics-to get an idea of system layouts.

Good link here -

No affiliation -mods -pls remove if infringement.

Title: Re: solar thermal how to connect to system
Post by: Ted on April 25, 2019, 10:24:53 AM
The normal setup would be to have a solar controller with at least 2 inputs for temps, 1 from the solar panel and 1 from the store so I would have expected your system to already have a sensor on the store.  Is this what your electrician means by 'thermostat'?

Navitron sell the Sorel range of solar controllers. These come with two or three inputs for temp sensors, 1 for the panel, 1 or 2 for the thermal store. The controller operates by checking the difference in temp between the panel and the store and turns the pump on/off according to the temps (the actual values can be programmed by the owner).

Manual here -