DNT is likely referring to the manufacturer DNTFIT which is a maker of quick fit connectors. The “1/4” is likely the slip fit size (this can be easily test with 1/4” tubing). I’m not as sure about the “22”, however this may be an abbreviation of the part number “PL 0202” which is a 1/4” slip fit to 1/4” threaded elbow
As a side note, my understanding is that the NPTF is a tapered thread that is usually used for fuel so I would look for NPT (not NPTF).
If my assumptions are correct, then you can look for a 1/4” thread quick fit at your local hardware store to see if it screws in correctly. Good luck!
NPTF is the fuel-thread version. The pitch and taper is the same as NPT, but the NPTF has a different crest form and responds differently when torqued. For this application, they're interchangeable to not matter.
However, the fitting on the unit is clearly not NPT(F)