Just interested to know if anybody has done this.
Our (new) Evohome system has the remote HW tank temp sensor for the indirect heating of the HW tank, but the HW tank is also heated by a Solar Thermal installation controlled by a Resol box. I can link to the Resol box to get it's temps and status in realtime.
The obvious problem is that the gas boiler will potentially run at the same time as the Solar because the Evohome controller gets the low temp from the remote sensor and fires up everything (which for us is just opening the HW Tank 2-way valve, which in turn gives the heat request to the boiler) at the same time as the Solar Thermal is heating the HW tank. This is obviously a seasonal issue but it does exist.
It's pretty straightforward to use the relay the Evohome controller is connected to be just a simple zero-volt relay and attach that to a Raspberry PI (or similar). Then I can merge the signals from the Resol and the Evohome and use my own software to decide if the gas boiler should be used (via a new mains relay) or to let the Solar Thermal heat everything. Which would, of course, be during the daylight hours when the hot water usage is low.
Anyone?
Our (new) Evohome system has the remote HW tank temp sensor for the indirect heating of the HW tank, but the HW tank is also heated by a Solar Thermal installation controlled by a Resol box. I can link to the Resol box to get it's temps and status in realtime.
The obvious problem is that the gas boiler will potentially run at the same time as the Solar because the Evohome controller gets the low temp from the remote sensor and fires up everything (which for us is just opening the HW Tank 2-way valve, which in turn gives the heat request to the boiler) at the same time as the Solar Thermal is heating the HW tank. This is obviously a seasonal issue but it does exist.
It's pretty straightforward to use the relay the Evohome controller is connected to be just a simple zero-volt relay and attach that to a Raspberry PI (or similar). Then I can merge the signals from the Resol and the Evohome and use my own software to decide if the gas boiler should be used (via a new mains relay) or to let the Solar Thermal heat everything. Which would, of course, be during the daylight hours when the hot water usage is low.
Anyone?
Comment