Underfloor heating pump not needed

The UFH pump to circulate water in the underfloor system is not needed. I want to remove and replace with a straight through pipe. What fittings would I need? The pump is a Grundfos UP S2 25-40/60. A combi boiler is the heat source so has a pump for CH. I wish to do this as I live on a boat, off grid, so power is an issue. It's not practical to have 2 pumps running.