Plumbing Notes/navien
Navien tankless install + service
We install, service, and repair Navien condensing tankless units across the Inland Empire, where hard water and 90s tract plumbing decide how long a heat exchanger actually lasts.
By Brad Staiger — Staiger Plumbing, LIC. #802197
What a clean install looks like
Most of the Navien units we hang go on a garage wall, and there is a reason the good ones look boring. Copper supply lines coming in clean, isolation valves on both the hot and cold so we can flush the unit later, stainless flex on the water side, and a PVC condensate drain run to a spot that actually drains. The yellow gas flex gets its own shutoff and a leak test before we ever fire it. We see a lot of Fontana and Rialto garages where the old tank sat for twenty years, and swapping to a Navien condensing unit means adding a condensate path the tank never needed. That PVC drain is not optional on a condensing unit. It pulls acidic water out of the exhaust, and if it dead-ends or runs uphill, you get problems down the line.
Hard water and the heat exchanger
The worst Navien we opened last season came in as a leak call. Pull the front cover and the heat exchanger casing was rusted right at the seam, with corrosion creeping along the wiring connections. That is almost always our water. The Inland Empire basin runs hard, and a condensing unit already makes acidic condensate inside the cabinet, so any drip that lands where it shouldn't eats metal fast. Homes from Norco to Chino Hills sit on expansive clay, and the same hard water that scales the bottom of a tank will scale a tankless heat exchanger from the inside until flow drops and the unit starts short-cycling. We flush these with a descaling pump through the isolation valves, and on units that were never flushed in five years the solution comes back out looking like tea. A unit that gets flushed once a year does not show up rusted at the seam.
E003, E010, E515
The fault codes scare people more than they should. E003 is an ignition fault, usually gas supply or a venting issue, and on a fresh install it often means the gas line is undersized for the unit's demand. E010 points at the air intake or exhaust being blocked or run too long. E515 is a board-side fault that sometimes clears and sometimes means the unit is done. We run into all three routinely across Riverside and San Bernardino county service calls. Half the E003s we get in Murrieta and Temecula are not the heater at all. They are a half-inch gas line feeding a unit that wants three-quarter, left over from when the appliance was a 40-gallon tank. We size the gas before we blame the board.
Where these units go
Not every unit lives in a garage. We mount them in closets with copper connections and isolation valves tucked tight to the wall, in exterior alcoves with the copper and gas flex coming in below, and in recessed stucco alcoves on the side of the house where a ladder and the access panel are the whole job. Exterior installs are common on the newer Murrieta and Menifee tracts that were plumbed for them, and they free up closet space, but they need the condensate handled and the unit rated for outdoor mounting. A closet install in an older Riverside home usually means we are adding combustion air and a vent path the room never had. Placement changes the venting, the drain, and the gas run, so we walk it before we quote it.
What this means for you
If you have a Navien, or you are thinking about one, the install details decide how the next ten years go. A correct gas size, a real condensate drain, isolation valves you can actually flush through, and one descaling a year against our hard water. That is the difference between a unit that throws an E003 in year two and one that just makes hot water. If yours is throwing a code or showing rust at the seam, we can tell you on the spot whether it is a flush, a part, or a replacement, and the estimate is free.