Recent content by SoCal Plumber

Isolate the hydronic lines and see if the issue is still occurring. If not, the check valve in the recirculating pump has failed causing a cross over in the plumbing. That’s a place to start, but it sounds like a cross over issue so any failed check valve could be causing the issue.

Was the venting corrected? Condensation build up in the exhaust can cause that. Your unit is either starving for gas or can’t “breath” properly, or both. If the condensation drain line is clogged it can cause the excess water in the exhaust vent, they are directly connected, as can an poorly...

There is NO benefit, there is a two way valve to turn inside the unit, as well, either INT or EXT. Set everything for Internal Pump and make sure your parameter settings are correct. Parameter setting P17 Enable Thermal Bypass, must turned ON. Both dip switches 1 and 2 are “on” but this is just...

If you haven’t stumbled across the information, Yes P17 should be on. This allows the Navien to heat water at lower flow rate. With P17 turned off, the flow rate (GPM) is set higher. Meaning the pump could be on and moving water but the flow sensor inside the unit will not start the combustion...