What can cause a machine to fail the on line PHT test? We have replaced the machine with one that was not doing this and that machine does it now. can the water pressure cause this? Or is it something else?

Check your deaeration pressure. This is what I always find the problem to be. If thats not it check the hanson and the lines outside the machine. good luck

I had that problem with one of my new K machines and found the vent tube in the back was getting pinched.

PS mgun, did you ever catch your destroyer?

mooshtech,
No I haven't caught them yet but we have the police involved now and the one I suspect is running scared after the monthly staff meeting.

Recal the dialysate pressure and your troubles are over. Trust me! While your at it, recal temp control and condo. Let me know.

Have you done any software upgrades on the Function board? When I upgraded some to the 10.06 I had a similar problem. Only some of them were doing it but others were not. After investigating I found that there is a dipswitch for Online PHT on the Function Board (I think it's # 6, but check the Tech book to be sure) that should have been turned off when the upgrade was completed (not in the directions for the upgrade, go figure lol). I was told that dipswitch being up 'enhances' the Online PHT. I don't know what the difference is but it worked when I turned it off. Never had another one fail. Hope that helps. :-)

Hi mgunsolus,
You stated that the machine that was failing the pht test was replaced and the replacement machine failed the pht test as well.
Do you have central delivery systems (bicarbonate or concentrate)?
I saw a machine failing pht test due to small air bubles entering throw the bicarbonate wand.
Good luck.