Use the moistener on your device to seal your envelopes. You can seal envelopes whether you are printing postage or only sealing the envelopes (no postage).
Check the level of sealing solution in the moistener tank. Add more if required.
Slide the envelope flap under the edge of the feed deck so the moistener can wet the flap.
Important: If the moistener tank is full and your envelopes are still not sealing correctly, clean the moistener brush and wick.