How to remove plastic supply line to dishwasher?

Question

I am trying to remove my current dishwasher and would like some advice on disconnecting the supply line.

The supply line to my dishwasher is connected to the shut-off valve with some sort of plastic coupler; the valve itself is connected similarly to the junction (picture below). I tried to undo the plastic coupler with a pair of pliers and it would not budge; I have avoided prying or cutting the coupler to avoid damage to the threading.

What is the best way to undo this type coupler?

Is it possible to keep the valve where it is and connect a conventional stainless steel supply line directly to it for the new dishwasher?

Thanks for any advice out there.

Answer 1

I ended up connecting the new dishwasher by cutting the 1/2" PEX supply line downstream of its respective valve, then using a push-fit adapter to transition it to the 3/8" compression inlet of the braided steel supply line that came with the new dishwasher.

For those interested, the configuration shown in the picture I posted uses a Wirsbo AquaPEX system; it is meant for quick installations with no soldering or threaded fittings. A collar is slipped over the end of some PEX tubing, protruding enough to cover the joint between the tubing and the intended fitting (about 1/16"). The collar and tubing are then mechanically expanded using a proprietary tool; once removed from the tool, the widened collar and tubing is connected to the intended fitting and will begin to contract back to the original diameters, creating a compression fit.

The collar can be removed using a utility knife and progressively deeper cuts. I experimented with the end I cut off (i.e. the end connected to the old dishwasher) and found that a heat gun can also be used to temporarily soften the collar and allow me to pry it off the joint; I slipped the collar back over the joint, re-applied the heat gun, and found that it contracted back to its original size and reformed the compression fit.

Thanks to those who took a look and gave this issue some thought. I hope the solution(s) I'm posting can help someone else with a similar issue. Take care, folks.