Should KH director be popping with the pinch valve throughout the sample

A little question

I have noticed that the KH director only pops once at the beginning of the test then I don't hear it it again where I think I remember hearing it popping throughout the test, not sure if there's an issue but it does click so I know the pinch valve works but not sure if something has changed? is there anything I can check? I opened it up and looked at the valve and it opens ok but strange it doesn't seem to click through the test? will this make a difference to the test result or is it not a big deal?

Regards Adam

If the tube of the reagent is keeped blocked you would get the error "Titration takes too long" or the tube would jump off because of overpressure.

Thank you for the reply, im not having an issue with it not performing the test what im asking is the kh director used to pop throughout the test when the reagent was dosing. (wasn't sure if it was to allow even smaller amounts being dosed?) but now it pops once at the beginning of the test and that is it so is there an issue here

No there is no issue, this sound occurs when the internal reagant tube gets unblocked. So if there would be an issue it would be one of the issues I mentioned.

OK great, sounds like the kh director used to have an issue with it keep popping but looks like its sorted itself out now.