Dessalator will be unresponsive because that is not a Dessalator-supplied pump. 

The one Dessalator used for the 160 has a 12mm mechanical seal. Most mechanical seals provide enough pressure on the 2 faces of the seal to seal water under pressure up to 6 bar. There is almost zero pressure on the Low-Pressure pump seals. I have not measured it, but likely less than 2 bar. I needed to replace this seal when I was in Penang Malaysia. I found a shop that had a box of them with no specifications whatsoever. I bought a 12mm seal and installed it. 8 years later it was still working.