So I had some problem with my gas furnace and a technician came by to install a new one but it doesn't have the same rating and only has one tube instead of two. He assures me it's fine but I thought all furnace repairs had to be made with OEM parts? Can anyone let me know if this is safe and if it will affect the life of my furnace?

The furnace is a Lennox ML195 Single stage 95% efficiency furnace. He replaced the whole pressure switch but the new one has only one port whereas the old one has two, so now there is a hose that is unconnected on one end. Also the old pressure switch has a rating of 0.90 PF and the new one says 0.27" WC is that the same?