Navien NCB240e Exhaust/Condensate Leak?

[jeff711981]

I have a Navien NCB240e combi-boiler. Last year after a lot of effort, I finally got it tuned in with the outdoor temp sensor and the proper curve to heat the house well and avoid short cycling.

However, I went down into my wonderful dirt floor basement to do annual maintenance on the DHW side and descale it with vinegar and I found this. Rusty water stains coming from the exhaust, and when I took the cover off to see if it went inside, it didn't, but the burner sight glass is very cloudy.

My plan here is to disassemble the exhaust tubing and replace the screws with stainless, first of all, but then do all the standard maintenance - cleaning the intake filter, cleaning the fresh water intake for the DHW side, cleaning the condensate trap, etc. and reassemble the exhaust tubing making sure everything is tight and sealed this time - any tips for sealing this properly? Is there any tape or putty I could/should use?

Should I be concerned about what I've found? Should I do anything about the sight glass? What would cause that, and is it normal? It's so crusty I can't see any flame at all through it, although the burner seems to light just fine and there's no signs of corrosion inside the boiler unit, just this "leakage" on top.

 

[Breplum]

I've seen the cloudy sight glass before, and just replaced, without ever figuring out why.
Street fittings on the exhaust are prohibited on the standard NPE water heater models, and I bet also prohibited on NCB models, probably because they do not fit fully into the full depth of the socket...hence the leak?

 

[Sponsor]

 

[WorthFlorida]

You did all the maintenance that sounds good for your condensation problem. Reading through the manual, the condensate trap may have been plugged up and causing a back up. (page 26)

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Navien's water heaters, boilers, hydro-furnaces & water treatment solutions provide innovative high-efficiency technology for residential & commercial projects.

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[Radiant heating newbie]

Hi all, I hope I can add this to the thread since I have bit of a similar issue. I have a NB-150 Navien. The water is leaking from the condensate line. I got the line all secured and then water is leaking from the bottom of the syphon. The interior of the boiler is bone dry. I took a look at the condensate trap and dumped the water and the gasket was in good shape but I swapped in a new one. The leak now shifted to the weep hole that is part of the condensate outlet. I called Navien support line and they said it could be a couple of things. One the filtration setup, back pressure from the condensate line or a blockage. I am thinking its one of the first two. I have a service tech coming in and troubleshoot. Any advice for us?

 

[Radiant heating newbie]

A service tech came and took a look. I told him it is such a tight space and the run is not very steep since the boiler is hung low maybe a condensate pump might help. In any case he prefers a gravity feed and then he talked to his boss and they email me an estimate that was outrageously high. In any case my boiler guy who was swamped finally showed up. Talking to him on the phone I told him what was happening prior to his visit. When he did show up he did one better. He went with a condensate filter with pump as one piece. That did the trick. If the condensate line gets clogged or screwed up I just need to replace the vinyl tubing line and the boiler and the filtration pump can be left alone. This is a better solution.

 

[vic9909]

Hi all, I hope I can add this to the thread since I have bit of a similar issue. I have a NB-150 Navien. The water is leaking from the condensate line. I got the line all secured and then water is leaking from the bottom of the syphon. The interior of the boiler is bone dry. I took a look at the condensate trap and dumped the water and the gasket was in good shape but I swapped in a new one. The leak now shifted to the weep hole that is part of the condensate outlet. I called Navien support line and they said it could be a couple of things. One the filtration setup, back pressure from the condensate line or a blockage. I am thinking its one of the first two. I have a service tech coming in and troubleshoot. Any advice for us?

Hi, very easy fix. I have a Navien CH-240 with a condensation leak (dirt trap leak). I went to Home Depot and bought an o-ring 1 inch + 1mm in size roughly 2.79 cm or 28mm in diameter from inner edge. Cost just $9. Put it in and it stops. Also it will be a nice snug tight fit. Put the pin back in. If it is not a tight fit it is wrong.