In principle, yes it could be possible if the diesel boiler is not an instant water heater with an integral pump. Some types of instant combi style boiler can be connected, but you would need to contact the manufacturer to check compatibility.
How you might connect a solid fuel boiler to a system is somewhat complicated. You have to consider a solid fuel heater has no thermostatic control so consideration has to be given to preventing the system water from boiling and providing an escape route for steam pressure if it does.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!