If the XV90 will be replacing an older, noncondensing furnace, the change means you will now have a furnace that produces condensate when it runs, as well as the AC condensing water in the summer. So you will be getting water throughout the heating season, not just a few weeks in the summer, and that may be why sales recommended the pump.getting quotes on a trane XV90 High efficiency gas hot air furnace ... sales person mentioned installing a pump that takes away the excess condensation that results from the AC operation ... not really sure if this is necessary for us since we're in the northeast and run the AC approx 2-3 weeks total in a season.