Navien NCB 180-E Professional Installation Not Matching Manufacturer Guidance

[Gordy67]

I had a Navien NCB-180E Combi Boiler installed several years ago. Recently problems have developed with overheating combustion chamber, error code 001, and shutdown. The professional installer replaced the circulator pump in the unit as indicated by Navien customer support. The problem resolved temporarily but after less than 12 hours, overheated with same error code 001 and reboot. I now can only use the hydronic heat side of the combi unit and not the domestic hot water side. In researching the installation, I noticed the installer (a professional HVAC business) did not follow the installation instructions to use a primary manifold or create a recirculating loop in the domestic heat side of the unit. Now dealing with expensive repair and trying to determine if installation could be responsible for the malfunction and need to repair and replace parts.

 

[Breplum]

First question: is the circulation pump running? I am Navien tankless WH trained, but NOT combis. Should be in the troubleshooting steps (wrench icon button) to run through to see GPM when there is a call for heat.
I don't even see 001 in the service manual.

 

[Sponsor]

 

[John Gayewski]

The combi units are usually setup as a primary secondary system. Meaning the boiler circulator just pumps the small loop to the header and back. You should have another circulator that circulates heating water or to your emitters and back to the small loop.

I don't know if using the combi in other than a primary secondary system would cause your error or not. Navien should know that,but I don't see how it could, unless the circulator inside of the navien doesn't pump enough to travel your whole system and back. I could see things overheating inside of the combi in such a case.

 

[Gordy67]

First question: is the circulation pump running? I am Navien tankless WH trained, but NOT combis. Should be in the troubleshooting steps (wrench icon button) to run through to see GPM when there is a call for heat.
I don't even see 001 in the service manual.

The original unit circulation pump was running when HVAC was onsite with Navien on the cellphone. Tech indicated he could hear pump running but Navien advised pump replacement, which occurred on follow-up visit since tech did not have part on the service vehicle. The new Navien pump did not resolve the problem. NCB-180 will run for minutes or several hours as a combi-unit before overheating to max combustion chamber temperature of 203 degrees F. Attached are 2 pics showing E001 (I also looked in manual and saw that errors start at E003 but several youtube videos depict E001 and resolutions), and high temp of 199-200 before displaying error code. The last photo shows the HVAC contractor installation with no Navien manifold or recommended primary loop (tee between supply and return).

 

[Gordy67]

The combi units are usually setup as a primary secondary system. Meaning the boiler circulator just pumps the small loop to the header and back. You should have another circulator that circulates heating water or to your emitters and back to the small loop.

I don't know if using the combi in other than a primary secondary system would cause your error or not. Navien should know that,but I don't see how it could, unless the circulator inside of the navien doesn't pump enough to travel your whole system and back. I could see things overheating inside of the combi in such a case.

Thanks for the reply, John. I provided additional information and pictures in reply to post from Breplum.

 

[Gordy67]

Primary (boiler) and Secondary (zone) installation instruction from Navien NCB manual.

 

[John Gayewski]

Primary (boiler) and Secondary (zone) installation instruction from Navien NCB manual.

But their manuals have several different installation applications described. This doesn't say their boiler can't be used in a single zone. It would be weird if you couldn't use this boiler that way. What's important is the circulator and zone info. You need more detail and troubleshooting information here. Not for me to do over the internet.

 

[Breplum]

Got to get a knowledgeable technician over and have them call Navien, unless you can convince them that you are a plumber so they will talk to you.

 

[Fitter30]

Primary manifold is for heat not dhw. Your pic page 2 fig2 shows a blue hydronic line coming off the cold water. That line feeds the boiler side and doesn't have to be installed there can be by the expansion tank. Dhw side when if ever has it been serviced and clean with vinegar?.

 

[Gordy67]

But their manuals have several different installation applications described. This doesn't say their boiler can't be used in a single zone. It would be weird if you couldn't use this boiler that way. What's important is the circulator and zone info. You need more detail and troubleshooting information here. Not for me to do over the internet.

It is a two-zone system. There are 2 thermostats, each wired to a zone control valve. There is one secondary (system) pump, a Taco-007. I was interested in the system lacking a primary loop as would be created if the installation had included the recommended Navien NCB-E manifold. There is no connection in the current heat system between supply and return as would have been created if the manifold had been used.

 

[Gordy67]

Primary manifold is for heat not dhw. Your pic page 2 fig2 shows a blue hydronic line coming off the cold water. That line feeds the boiler side and doesn't have to be installed there can be by the expansion tank. Dhw side when if ever has it been serviced and clean with vinegar?.

I flush the dhw side of the NCB-180, annually, using white vinegar (takes about 2 gallons). I recirculate through the dhw side using 1/4 hp sump pump in 5 gallon bucket for 30-35 minutes, and follow with clear water for about 2 minutes. I clean the dhw inlet filter and condensate trap, also one per year.

 

[Gordy67]

Got to get a knowledgeable technician over and have them call Navien, unless you can convince them that you are a plumber so they will talk to you.

I am learning as much as I can online about Navien combi boilers. In my area, being low population, there are no Navien trained technicians/contractors within 50 miles. Contractor that installed the unit is not listed as a Navien Service Specialist, installer or service provider.

 

[Gordy67]

Regarding the recirculating loop in the domestic heat side of the unit that is currently not present, I've read that the connection should be no longer than 4x the diameter of the supply - return plumbing. Since these are 1 inch, separation should be 4 inches or less. The only way I can see to accomplish is to install the T in location shown in the picture below (black line). If I use the red line location the distance is 7 inches.