Having just inherited a unit with 3 renatrons, what do you look for when one fails pressure test upon start up. I changed the o rings and checked all the outside hoses and connections. Thanks.

Is the Renatron failing in step d2, h2 or in step 36 or 39?

The Renatron can fail because it cannot build vacuum (steps d2 and 36) or because it cannot hold vacuum (steps h2 and 39).

A failure in d2 or 36 can be caused by low water pressure, a bad jet pump, bad reprocessing connectors (step d2 only), or a bad V5 or V7 plunger (step 36 only).

A failure in h2 can be caused by bad reprocessing connectorsors. A failure in step 39 can be caused by bad hansen o-rings, bad V4,6,9,or 11 plunger or bad colder quick connects.

Thanks penguin - It was a bad plunger on valve 11.