Navien Tankless Hotwater Heater Leaking

We have a slow leak from the outlet for the Navien's Recirculation Return Connection (RCC). We don't employ an external (through the home) recirculation system, so the return is capped. It's the cap with yellow duct tape on it, next to the Cold Water Inlet Connection (CWIC), in the photo below (I insulated the cold water copper piping in case it was collecting condensation).

Navien NR-180A Tankless Hotwater Heater from the front

We are using the internal circulation mode to speed up hot water delivery to our bathroom outlets. I'm concerned that the circulation pump or 3-Way Valve may be leaking, and water collection in the bottom of the tank is leaking through the capped RCC. The Inlet Water Filter may also be dirty, and this could cause a leak.

Note also the venting for the room, which runs right along side the water and drain pipes (the Navien will sit above this vent). I'm not sure this venting is required. The vent drops very cold air into the room during winter, and may freeze water in the pipes. There is a gas furnace in the room, but it is vented separately.

Vent to outside right under where the Navien will be installed.

Another Navien Repair

I'll say this for the standard hot water heater -- the kind with a tank -- it doesn't have a lot of moving parts and it certainly doesn't have a lot of electronics. The same can't be said for the typical tankless hot water heater. Just look at the Navien.

Navien NR-180A Tankless Hot Water Heater

The more stuff you cram into these 17" x 28" x 14" boxes, the more can go wrong. We've had problems with our system ever since it was installed in December 2010. The last fix was replacement of the flame rod assembly. Before that, we had to cut into the wall and pull the exhaust pipe down to create an incline for the condensate to drain properly.

This time around the problem was the air pressure sensor (APS). The new APS Pt# was 30000663A, and replacing it also required replacing the whole damned printed circuit board (PCB), Pt# 30000182A.

The APS is located at the top, right side of the unit.

This job went fast, less than an hour, once the problem was diagnosed, and it took time on the phone with Navien tech support to figure out what was wrong. We had, at different times, error codes 3, 10, and 12; ignition failure, abnormal air pressure, and flame loss. None of these codes made reference to the APS or the PCB.

Navien Tankless Water Heater Flame Rod Replacement

Due to continued "failure to ignite" problems (Error Code #3), we recently had the flame rod assembly on the Navien NR-180(A) replaced.

Old flame rod assembly showing oxidation and increased gap

Flame Rod Assembly Pt#30004680A

Adjusting Inclination of Navien Exhaust Pipe

See a previous post for an explanation of why this repair is being done.

Removing Navien connection to exhaust pipe

Sheet rock cut out around inlet and exhaust pipes

Condensate (~1.5") trapped in exhaust pipe

Original set of exhaust pipe

Exhaust pipe hole expanded and pipe lowered

Cover placed over open sheet rock space

Piping refit to Navien

Studying the Navien Problem

As indicated in an earlier blog post, we have had problems with our Navien NR-180A-NG tankless hot water system each winter since its installation. The system fails to ignite (Error Code E003), and thus won't deliver hot water. This happens only during winter weather, i.e., when it's very cold outside. The last time it happened was in January 2013. The error code displayed then was E027, "Abnormal activity of the air pressure sensor."

One of the theories for why we're experiencing this problem is buildup of condensate in the flue that exhausts hot air from the Navien. The flue piping has a long level section that elbows up (see photo) and water could collect here in the winter, since outside air will be cold and make the pipe cold. If enough water is collecting there, it may be blocking exhaust enough so that the system senses an air pressure problem. We've been able to reboot (unplug and plug) the system and get it working again.

Matt and Chris Q of Campbell & Company were out today to examine the system and discuss what might be done to correct the problem. It was generally agreed that the long run of the vent pipe and failure to slope the pipe the designated amount (1/4" per foot) is the major contributing factor in the system failures during cold weather. However, Matt hypothesized that another factor may be the fact that the cold air in the winter is harder to move through the long exhaust pipe. The combination of the condensate building up in the pipe and the added difficulty of moving the heavier cold air may be causing the air pressure anomaly and failure to ignite.

We hesitate to go in and realign the exhaust pipe because it is housed in a chase for cosmetic reasons (see photo below).

Matt disconnected the intake pipe on the Navien so that warm air is being drawn from inside the home (see photo below), rather than outside. We'll see if this fixes the problem when the weather turns cold. If not, we'll have to cut a hole in the chase where the vent pipe is located and attempt to incline the pipe and exhaust it directly under the deck instead of on the roof.

Update: 3302 W 42nd, June 2013

Installation of a nuvoH2O Water Treatment System

We've been in our new home a little over 2 years and decided it's time to do something about the hard water. I'm not sure what the hardness level is, but we've been getting buildup in the dishwasher, and on shower doors.

We had a water "softener" in our previous home and had it removed after a few years because of continued reliability problems, plus we were never happy with using salt to soften our water. We had the new home plumbed for a water softener, but hadn't decided yet what we wanted to use for water treatment.

After doing some research, I decided to install a system that uses chelation to remove the hardening agents. The system we chose was the nuvoH2O.

According to the nuvoH2O web site;
"The nuvoH2O Manor system uses revolutionary technology to lower the PH level of water based on the basic scientific process of chelation in which the metal ions causing hard water, principally calcium and magnesium, are bound to the chelating agent in nuvoH2O's FDA-approved, proprietary formulation, which keeps the minerals soluble and unable to cause hard water problems. The resulting water is soft and healthy for all of your household uses, including drinking, bathing, washing, and lawn and plant watering."

Although the web site advises that the system can be self-installed, I decided to hire my plumber to handle it. I'm glad I did. Their special tools and expertise made it an easier job than it would've been for me.

nuvoH2O system was placed next to the Navien tankless hotwater heater

PEX pipe was used for piping and a ProPEX Expander tool was useful in the installation

Completed installation

After we've used the nuvoH2O system a couple of months, I'll blog about what I think of it. I'll also show how the canister filter is removed and replaced.

Navien Water Heater Problems

We are having intermittent problems with our tankless water heater. The system is a Navien NR-180A-NG (operates on natural gas). It was installed in December 2010. The system sometimes fails to deliver hot water. Water will flow, but it's cold. This problem only occurs in the winter.

Examination of the control panel indicates the system is in error mode (red light flashing). I didn't note the error code (will do that next time). The system can be restarted by unplugging it and plugging it back in. This morning it took several tries and about 15 minutes to get the system working.

The service tech examined the system and ran some tests, but when he arrived the system was working and he couldn't duplicate the malfunction. He did set an internal recirculation system (we did not get the external recirculation) so the system is supposed to circulate hot water internally from 0600 to 0900 and from 1800 to 2100. This might improve the time it takes to get hot water to various locations in the house, but it's hard to see how it will help the intermittent problem.

One of the theories for why we're having a problem is buildup of condensate in the flue that exhausts hot air from the Navien. The flue piping has a level section that elbows up (see photo) and water could collect here in the winter, since outside air will be cold and make the pipe cold. If enough water is collecting there, it may be blocking exhaust enough so that the system overheats. We'll have to see what the error code tells us next time the system fails.

Vent flue (horizontal) and air intake for tankless water heater.
Flue enters inside wall of garage and goes straight up to roof.
This piping is now contained in a chase.

Update: 3302 W 42nd Pl, June 2012

3302 W 42nd PL, Kennewick, Washington

Locating the Source of the Leak

Double A Plumbing removed drywall to inspect drains and discovered that the source of the leak was a cracked condensate drain pipe. The pipe was apparently cracked when the duct for the room vent was installed, either at the time of installation, or from the pressure that was put on the pipe, which made it vulnerable to cracking during cold, winter temperatures.

Photos below show the drains roughed in vertical, the installation of the vent and duct, the pipe bent to the left beside the duct, and the leak.

Source of Leak in Storage Room

Taking a Closer Look at the Leak

I removed the baseboard and about 3 inches of the drywall. This is what I found.

It is wettest underneath the vent. Insulation is wet there, whereas it is not on either side of the cutout. The photos below show what's behind that vent.