The maximum temperature this particular 4kW electric boiler will reach is 60 degrees, so with a bit adjustment it could be set to run at 55 degrees the design flow temperature of the UFH circuit, but presumably the system works better by blending the slightly hotter water from the boiler circuit with the return flow from the UFH.


There is an issue other than being told I have wired up too many pumps that I have not got clear in my head yet.


The actuators on the UFH don’t immediately respond to signals from the UFH controller, there is a 2-3 minute delay between getting the signal and being fully open, but the boiler “fires” immediately upon receiving the signal from the UFH controller, then overheats and locks out, this is made worse because the bypass has not been installed. I spoke to another plumber this morning and he questioned why the UFH controller fires the boiler before the actuators are fully open, but as far as I can see that is what supposed to happen with the bypass returning the water to the boiler and its thermostat controlling the boiler circuit flow temperature, but the boiler thermostat is on the boiler return and is not able to operate correctly without the water circulating.

The maximum temperature this particular 4kW electric boiler will reach is 60 degrees, so with a bit adjustment it could be set to run at 55 degrees the design flow temperature of the UFH circuit, but presumably the system works better by blending the slightly hotter water from the boiler circuit with the return flow from the UFH.


There is an issue other than being told I have wired up too many pumps that I have not got clear in my head yet.


The actuators on the UFH don’t immediately respond to signals from the UFH controller, there is a 2-3 minute delay between getting the signal and being fully open, but the boiler “fires” immediately upon receiving the signal from the UFH controller, then overheats and locks out, this is made worse because the bypass has not been installed. I spoke to another plumber this morning and he questioned why the UFH controller fires the boiler before the actuators are fully open, but as far as I can see that is what supposed to happen with the bypass returning the water to the boiler and its thermostat controlling the boiler circuit flow temperature, but the boiler thermostat is on the boiler return and is not able to operate correctly without the water circulating.