Who installed the boiler stove, if the system no longer works when it did before then ideally you need to get them back......continued lighting is a big no no if you have no gravity flow to higher levels. Make sure the system is fully filled, can you bleed water from upstairs rads , does water flow from hot taps , no boiler litInstall boiler stove using same plumbing from old back boiler fire. Got radiators downstairs but no hot water or radiators upstairs tried putting t piece in to get air out but still not working.
the gravity feed still not working