Running an electric boiler from grid-connected PV solar panels
You are right. Grid-tie inverters supply standard mains AC to the grid. So, really, the solar panels and boiler are two completely separate things that don't affect each other as far as compatibility goes. The boiler will never know you even have solar panels. I suspect the boiler person misunderstood what you were proposing to do.
&quot;Hob&quot; as you are using it is not a common word here in the US. I am not 100 percent clear on what it means other than it supplies heat somehow for some purpose and that there are gas versions as well as electric versions.
Just a comment on system design. Solar availability and heat demand don't line up very well in most places. If you have long periods when it is cold out and the days are short or cloudy, you can't expect the solar panels to supply enough power to offset the electricity you consume from the grid. This is not necessarily a problem, but I just want to make sure your expectations are realistic.
Switching a major heating appliance from gas to electric is going to increase your electric use noticeably. Your electric bill might go up during the cold season even though you have solar panels.