While new MF series models are no longer for sale to residential customers in the US, we will still be able to get any and all parts an MF furnaces could need. There is no prohibition in the 2015 NSPS on repairing old units. Heatmaster SS is committed to taking care of their customers for the long haul.
New MF series units are still be available for commercial use only. Installing to a residence is prohibited. Shops, greenhouses, farm buildings, garages, pools etc. are acceptable.