Combi boiler gas valve problem

schultzey11

Having an error code 11 on a Noritz CB199 combi boiler. Installed Jan 5th 2021 and it's been doing a nice job of dhw and radiant duties for about 6 or so weeks. I've cleaned the ignitor and verified 8 in h20 coming into unit. I can see spark in the heat exchanger through the window so unless it's "weak" I feel as though I have ignition. I hear the gas valve assembly solenoid click on and off during ignition. I can also measure 110 vac for the 2 seconds during ignition so the coil is getting a signal. I don't know if the valve is actually work however, but I feel as though I have way to much fuel or I'm not getting any.

This first happened earlier this week and I got it to run again Friday, but it quite this morning. I've been talking with Noritz tech but we haven't gotten to the bottom of this yet and it's Sunday. I'll plan to call again tomorrow but they've been slammed.

I think I'm dealing with a faulty solenoid valve on the gas valve, but they have special screws on this thing I don't have bits for to diagnose further.







Any thoughts are appreciated.

kcopp

That is a 2# set up/
The distance from the maxitrol 325 to the boiler inlet is much, much too close.
That is most likely the issue. Really need a 6-10 feet.

schultzey11

Hey thanks for the quick response.  How do you know how far away to install it, neither manuals say anything.

kcopp

That info comes from many years of lurking on here... @Tim McElwain would be the better person to answer that question.

mattmia2

i believe it comes from the fuel gas code. Did anyone do a combustion analysis on it when it was installed?

HVACNUT

If you don't have the correct tools, a manometer, and a combustion analyzer, then what  is tech support going to be able to tell you? They're not supposed to deal with the end user anyway. Even if the end user is also the installer. 
If you did the installation, terrific. Now get a certified tech to test and adjust. 

schultzey11

When it was running the combustion analysis looked good on low fire. I didn't get a print out however the ppm on co and co2 were close to the target from the manual. I have it written down at home, but don't have it right now. Gas inch h20 was also in spec. I do have a combustion analyzer and manometer. Right now I'm not even able to get it to fire, so before I worry about the analyzer I need to diagnose why it won't fire.

The two o-rings now have developed leak at the bottom of the heat exchanger. Didn't even touch that while re-piping the gas last night. Gas re-piped per @kcopp feedback around 6'. Will retest firing once water leak is fixed. O-rings looked perfectly fine, but the water inlet pipe to the heat exchanger isn't completely square, which is what I'm guessing is leaking.



Again thanks for any helpful feedback or ideas anyone has.

schultzey11

Fixed the leak tonight no thanks to the tech support (after a 2 hour wait). They wanted a picture of the drip... to understand where the leak was. I described it and sent a picture of the area that I had disconnected to try and fix it on my own. We went back a forth with the tech unwilling to help at all until he had a picture of the actual drip. I just wanted a simple, "hey we've seen this before, try this..." but couldn't get it. I couldn't help but notice about the time the tech insisted we end the call it was the end of support hours. Hmm. Not one of the better experiences I've had over my years with folks tech support lines.

Anyways now that I have the leak fixed and regulator re-plumed, the boiler started after it did a lengthy fill cylce (to refill after the leak). After this I ran another low fire boiler test and what I noticed is the manifold pressure was dancing but not locking on the recommended number. I only have one manometer (digital) but when my hvac contractor comes back I'll have him check with his analog one. My combustion on low measured decent per the manual for co2.

Some else Interesting is that prior to doing testing in low fire and just doing a dhw call, the boiler had a rythmic sound to it (not normal) almost as if the intake was being pulsed with a strong breeze from outside. I went outside to check and it was calm tonight. This may be an indication of the lack of a good combustion because this sound was not typical while this unit was running well the first 6 weeks.

High fire had a similar story, co2 looked good per the manual but manifold pressure was dancing. Water seemed hot so I told the wire to hurry up and shower. About the time she got in and I went back downstairs (after several minutes of the unit firing on high fire seeming to work well - 2 showers calling) the flame goes out and she's get stuck with cold water. Water column was still within the boiler recommended range when I was looking but after 10 ignition attempts it gave the error 11 (er.11) code again. It wouldn't re light. I still feel like I'm dealing with a gas valve, but I will follow up again with tech tomorrow to try getting to the bottom of this.

Maybe if nothing else this post will help someone else out there at some point.

Link to hire fire video - manometer again not locking on setting - all over the place.

https://photos.app.goo.gl/Xg8kR14jD6FLMZVv7

Again helpful comments appreciated.

I'm not able to upload or attach my three photos for some reason. The draft also wouldn't save. I'm posting this and will try again tomorrow to upload the photos. See video link above for high fire readings.

EBEBRATT-Ed

I think the problem is your gas supply.

A regulator isn't a regulator. It has to be sized correctly. I am willing to bet with 2lb inlet pressure that regulator is way oversized. That will make the gas pressure fluctuate.


Post the model # of that regulator and I will look it up

schultzey11

Dormont R625N-0711-08BX.

https://www.menards.com/main/plumbing/pipe-fittings/flexible-gas-pipe-fittings-accessories/dormont-reg-1-2-natural-gas-appliance-regulator/0242495/plumbing/pipe-fittings/flexible-gas-pipe-fittings-accessories/dormont-reg-3-4-natural-gas-appliance-regulator/0242496/p-1444446181030.htm

Photos that wouldn't post yesterday. Boiler image is when on low fire.





Photos of gas line update, gas valve internals and regulator.



If tool small I can upload a single one to see better.

PS I didn't find anything gasket / diaphragm wise on the internals of the gas valve that is damaged or plugged. It leads me to think it is coil / valve related, but Noritz tech said since we measured a spike the valve must be replaced.

Amodedude1

Hey, did you ever find an answer to this? I have the same CB-199DV. I don't have any issues (yet) but am curious if you ever solved it. Did re-piping the gas supply fix it? I find it funny that after posting the Analyzer results everyone stopped trying to help.
...

Anyway, hope you solved it!