navien 240

I have been helping a friend with a combi unit (Navien CH-240 ASME) issue and am in need of some advice... I maintain my own tankless system but only for DHW so I know enough to be dangerous! Hopefully this is the right forum for this topic. Short story: What started with a small leak at the...

Hi All - Bone-Headedly I introduced quite a bit of air to my system. I theoretically thought I knew what to do, but am having all sorts of trouble in practice. this system is a few years old and i usually do have my local guys service who are great, but i wanted to get in there and clean some...

Hi all, as the title suggests I recently had a NCB 240/110H installed with an external Grundfos Comfort PM circulator pump (circled in image). When we first installed it, the hot water seemed instant and HOT. DHW temp set at 130F. Scalding within 10-15 seconds at every tap in the house. Then...

Hey! Thanks in advance for taking a look at my post if it is being discussed elsewhere please let me know. My Navien NPE-240A2 has been working great for 2 years but over the last month has not been consistently providing hot water in 1 shower. There are no error codes. The other shower and all...

We keep getting a 110 error which is an issue with air flow on the exhaust side it seems. I checked the exhaust pipe and for some reason it sounds like we have some water in there which may be causing a slight blockage in the exhaust pipe. Im sucking that little bit of water out to see if that...

Hi everyone, Could a leaking siphon tube also result in gas escaping from a Navien CH-240 boiler? I know - Naviens are fussy. But my CH-240 from back in 2010 has been humming along until just the other day. I found that it has begun leaking from the top of the "siphon hose" where it connects...

Navien is about 8-9 years old and never had any problems until the last year . When we use the hot water the pex will vibrate like crazy for 5-20 seconds. Cold water is fine. Sounds as if the flows restricted on the incoming line? I will double check the main shit off is all the way open...

Navien Not Heating Baseboards but Heating Faucets I have a Navien comb boiler NCB-240/110HNG for baseboard hydro heating and taps/DHW. I use Ecobee thermostats and turned off calls for hot water when we had a heat spell. I've since turned on our heating and my thermostats (two zones) have been...

I have a multi family house consisting of 4 apartments. The thermostat is set in the high 70's but can't seem to pass 69-70. We are currently in a cold weather season and tenants are complaining that it is cold inside. I had the unit along with all the pipes installed two years ago. The tech had...

I’ll keep this as short as possible. I’ve read the manual and scoured the internet and have yet to find a clear answer here. I have a brand new Navien NCB 240e that so far has given me nothing but problems. However, I’m slowly finding out that my problems are from an incompetent installer and...

I am curious what the best settings for my system would be as the installer has been less than helpful. This is our second winter here and after heating the house last year with the in floor it didn’t like to keep up in the very back corner of our house which happens to be the master bedroom. I...

My old gas water heater was replaced with a Navien gas tankless NPE 240A2. The old water heater was located in a small closet that was built into the outside of the house that has a door with a vent screen in it. This is where the Navien was installed. Instead of venting it with pipe and...

This summer I bought a house that has a Navien NCB 240E installed. I've been reading the manuals and this forum trying to understand the system, and in particular the best way to operate the heating for the winter. First, some details of the house: - old house, completely renovated down to the...

Hydro coil in the airhandler bursted. Had a guy came to replace the coil, initially the boiler was showing e02 (low water pressure in the heating side), he messed with it a little bit (drained, purged air etc) and got it working. but a few hours later e02 came back and it's not working again...

Hello, I ordered an ecobee thermostat. Now that it has arrived, I have found out I only have two wires R and W going into my thermostat. I have a tankless combi boiler which provides me hot water and fulfills my heating needs. I have 4 zones and all thermostats are connected with two...

Hey all, So let me describe my problem first and then I'll describe the specifics of my installation. The Problem: Over the past 2 weeks we have began experiencing the cold water sandwich for the first time since installation. It doesn't"t happen consistently, but when it does we often go from...

We have a Navien NB-240 with the Heating set at 82C and DHW set at 45C. When we run the hot water, the first minute or two comes out scalding hot. After that, it goes to the set temperature. Even when we lower the DHW temp the first minute is still the same. Any ideas? Thanks!

I had a Navien NCB240 installed about 1 year ago and I have always thought that the installers design for the closed loop side was a bit odd/wrong. He didn't use the Navien manifold accessory and instead built a simple loop with the supply at the top and return at the bottom with a recirculator...

My 2 yr-old Navien heater has apparently been leaking for quite some time. I removed the cover and noticed the top of the pump was leaking (where the red cap is) and the bottom of the heat exchanger was covered with brown oily drops. Navien phone support says there is no oil in the system that...

my navien started acting a little weird lately so i started to look into it... really a beginner in this stuff please bare with me if my questions are obvious... the problem mainly is the hot water from DHW side isn't consistently hot, bounce between hot and cold while running. also sometimes...