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Navien CH-240 Knocking and error code 16

I am new to this site and looking for some help getting my Navien CH-240 working properly. It was installed a couple of years ago by the local HVAC/Boiler company in town. It has only been hooked up for the 3 zone (basement concrete, garage concrete and main floor) radiant heat and has never been hooked up for DHW. It hasnever worked for longer than a week without shutting itself off and throwing the error code 016 (overheating).
My main problem is getting it started. I have worked on purging all of the air out of the boiler, but as soon as I turn it on and the flames kick on in the burner, I can hear the knocking of air in the boiler. I try to bleed it off with the plastic knob up top inside the boiler and the brass knob in back inside the boiler and lots of air comes rushing and knocking. Then the boiler overheats and shuts off, displaying error code 016 on the digital display.
Once in a while I will get the boiler running properly for a few days and then I have other temperature and flow issues. I am wondering if I should add a Grundfos 15-58 FC circulator to the primary loop return side to help pull the cold return water back to the boiler. It seems that my closely spaced tees are getting cooled off because the zone pumps are pulling the cold water back through the zone loop and not letting it go back to the boiler.
I am attaching pictures of my installation below. Thank you ahead of time for any and all help!




My main problem is getting it started. I have worked on purging all of the air out of the boiler, but as soon as I turn it on and the flames kick on in the burner, I can hear the knocking of air in the boiler. I try to bleed it off with the plastic knob up top inside the boiler and the brass knob in back inside the boiler and lots of air comes rushing and knocking. Then the boiler overheats and shuts off, displaying error code 016 on the digital display.
Once in a while I will get the boiler running properly for a few days and then I have other temperature and flow issues. I am wondering if I should add a Grundfos 15-58 FC circulator to the primary loop return side to help pull the cold return water back to the boiler. It seems that my closely spaced tees are getting cooled off because the zone pumps are pulling the cold water back through the zone loop and not letting it go back to the boiler.
I am attaching pictures of my installation below. Thank you ahead of time for any and all help!





DWatson
0
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Comments
The symptoms , and lock out are signs of low or no flow condition causing the water in the HX to flash to steam not good.
That is exactly my problem. The boiler is ramping up to 220+ degrees (flashing to steam) and then shuts off. We just put in a new Navien circulator pump 2 weeks ago. If I turn off all zones I should get flow through the primary loop?
Thank you.
If the boiler is putting out 180 and dropping to 80 before it gets to the secondary t I'm perplexed if that's what you are trying to say? How are you measuring those temps? Boiler read out, and how at the pipe before it ts?
The mod to the piping is not helping any take off for a zone off the primary should happen with closely spaced t's otherwise you are not hydraulically decoupled from the primary loop.
Have you looked at the piping schematics per the ch 210 manual?
1. You do not want to add another pump in series with the boiler pump. You won't get the proper flow rate and it will dead head when the 3way valve switches over for domestic heating.
2. Your circ's MUST be mounted with the motor horizontal, not vertical as they are now.
3. I don't know for sure about the brand of manifolds that you have, but the ones that I use put the flow setters on the supply, not the return. They have internal checks that won't allow reverse flow. Yours appear to be piped backwards and if so, then the checks would not allow flow like that.
4. The reason your flashing to steam is your piping arrangement. The secondary is not pulling anything out of the primary loop. You need to remove the extra taps that appear to be bypasses and let the secondary pull everything through the closely spaced Tees. Also, confirm #3 about your manifolds.
5. What's the static fill pressure on the boiler when cold?
You can choose to do what you want, but you cannot choose the consequences.
I just put in the extra bypasses today to try to get more heat to my supply on the secondary loop. I will take this out.
Can I rotate my pumps a quarter turn to get the motor horizontal? The webstone valves have the rotating flange.
I have attached a close-up of my manifolds. My installer did not give me any specific information on these
.
What brand are the manifolds? They look like Rifeng - a Chinese knock off.
You can choose to do what you want, but you cannot choose the consequences.
The simplest solution would be to close the ball valves on both, relieve the pressure through the drain port, disconnect each loop as well as the ball valves from the manifolds and reverse them. Then, after everything is re-connected, purge the air from the manifolds. If they are above the loops, then the manifolds should be the only place that got air in.
I don't have much confidence in your installer's knowledge of hydronics if he made that kind of mistake. Please try to get him to frequent this site as it would be a great help to him gaining knowledge.
You can choose to do what you want, but you cannot choose the consequences.
I will get the circulators rotated, close off the extra bypass coming off of the primary loop and then see if I can get it fired up. Should I look into getting different manifolds?
I really appreciate all of the help. I can't wait to get this working the way it should.
I wouldn't get new manifolds at this point, I would simply get those installed right as long as they have no issues.
If your flashing to steam in the boiler (sure looks like it), then the only reason is because of lack of flow. Beyond the most prevalent cause of no flow, which is air binding, piping and / or pumping are the next places to look. Your piping is wrong in the two areas that we've pointed out: the bypass loops and the manifolds connected backwards. Start there and see if those things correct your problems.
You can choose to do what you want, but you cannot choose the consequences.
I will get started on the changes suggested tonight. Thanks
trainer for Caleffi NA
Living the hydronic dream
Where IS the primary pump?
If you are NOT getting air out of potable water faucets in the house, you are not getting air from your well and pump. Even if the water level in the well was dropping to the level of the pump.
Don't put a second pump in series on that loop.
P/s piping allows you to be able to have different flow rates that's the reason for it
You have to think like air.
Make sure your loop is wide open at the manifolds.
Purge each loop individually then isolate, and move to the next. Work farthest from the boiler then back.
Pumps off while doing this.
Once your done then open all loops at the manifolds.
If you want to see if your DW is putting air in the system...doubtful. Put the hose in a bucket of water see if air bubbles emerge. Make sure the hose has no air in it first. That brings me back to making sure the hose was full of water not air when first hooked to the system when purging otherwise you just added a hose full of air to purge. The longer the hose the more air you added before purging begins.
You are not able to add water to the hydronic part of the system via a pressure reducing valve with fast fill feature?
In the Navien error code book, under solutions for error code one it says to check the automatic flow valve. Do you know where this is at?