I am having an issue with one of our vans leaking from the hose that goes from the recovery tank. i inspected it and found that there had been a previous repair to the pipe that runs to the 90" to run down under the van, as there was a piece of heater hose that was covering a preexisting hole. As i tried to dismantle the piping going to the drain valve i noticed the piping had been glued together. is it supposed to be glued? if so (or not) will i have to replace the piping to replace the drain valve?