Navien CH-240 Knocking and error code 16

SoundPipes

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!

Gordy

In the pic 4 your pulling water off the primary loop with out closely spaced t's what's that supplying looks kinda weird to be piped like that. That circ may be creating flow issues with the boiler circ because there are not closely spaced t's.

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.

SoundPipes

Thanks for the reply Gordy. I just put this pipe in today. I thought it would help increase my water supply temp since I was loosing most of my hot water at the closely spaced Tee's. When the boiler runs, it will output 160 - 170 degree water and by the time it gets to the supply manifolds it is down to 80 degrees.

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?

SoundPipes

I am considering putting the Grundfos circulator in my primary loop on the return side. Would this improve the flow through the boiler and keep it the water from flashing to steam and shutting down. I do think I have a greater flow in my secondary loops compared to my primary loop and am loosing most of my heated water to a reverse flow between the closely spaced tee's. Any ideas.

Thank you.

Gordy

The idea behind primary secondary piping is hydraulically decoupling the flow rates through closely spaced T's that way if you need say 6 gpm for a secondary loop the primary can still flow at say 4 gpm or vice versa.

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?

Gordy

One more thing what is the heating side system pressure? At ambient temp. And those pumps don't like to be oriented as they are. And did you install the new pump flowing in the right direction?

SoundPipes

The system pressure fluctuates anywhere from 12 psi to about 27 psi. When running stable the system pressure remains stable at one pressure. Although it is hard to tell since it does not run very long or reliably. I am unable to get it started and running because it turns to steam in the Heat ex-changer and errors out. Once I tore apart the original design from my installer (which included a 40 gallon tank and did not have closely spaced tee's), I followed the Navien CH-240 installation manual and put in the primary and secondary loops. Since doing this in the last 2 weeks, the boiler has ran at times but with the large temperature drop. The boiler gives me a water temp read-out on the display usually 165 to 170 degrees. I could not touch the pipe at all before the first closely spaced T, but could hardly feel any heat on the first closely spaced T. Also the supply manifold going into the basement floor has a temperature gauge and it would ready 75 to 80 degrees going into the floor.

SoundPipes

I am preparing to put in a Grundfos 15-58 FC on the primary loop. Do you think this would increase the flow through the heat ex-changer or am I wasting my time? Thank you.

Ironman

In addition to what Gordy noted:

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?

Gordy

Where's HDE tonight

SoundPipes

Thank you for your reply. I'm not sure about the static fill pressure when cold. The readout on the Navien will read different pressures at different times since it won't run for more than a few days until it shut off with error code 016

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

.

Ironman

SoundPipes said:

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

.

Yes, you can loosen the flange bolts and rotate the circ's. Of course, you should shut the valves first.

What brand are the manifolds? They look like Rifeng - a Chinese knock off.

SoundPipes

It has the marking of DN25 on the manifold.

Gordy

I think Ironman is onto something with the manifolds being reversed. I also hope the copious amounts of pipe dope did not find its way in the piping could wreak havoc with the manifolds.

Ironman

Your manifolds are indeed piped backwards. The YouTube link below confirms this.

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.

Gordy

And undo your piping mod

SoundPipes

If the manifolds were reversed would it run at all? It has worked fine with hot flow in and out of the manifolds. The circulators push water through them fine. I have also isolated the manifolds and purged air through each individual loop. I did keep the tape and pipe dope 2 threads back from the edge.

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.

Ironman

I can't tell from their literature if they have flow checks, but good ones do. Still, there's no way you can know or set flow rates with them connected backwards.

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.

Gordy

Have you ever observed the flow meters working? Were flow rates set by installer? All,you have to do is move,the top one down, and the bottom one up. Take care to make sure you don't mix up the pipe connections.

SoundPipes

No, I haven't ever observed the flow meters working. I'm not even sure how they work or set. I was not given any information on what the flow rates were set at.

I will get started on the changes suggested tonight. Thanks

Gordy

Did he leave the wrench to adjust them?.

SoundPipes

No he did not. I have attached a couple pictures of my work this evening. I have the bypass sealed off, the grundfos cir motors turned horizontal and almost one manifold switched out.

SoundPipes

hot_rod

where's the primary loop circa? If the black iron piping is the boiler primary loop, I don't see a pump in that circuit. Unless it is in the boiler somewhere?

Gordy

It's onboard ....moving copious amounts of btus at 5gpm about. The Navien primary loop thickens.

SoundPipes

I have switched out the basement manifold that was backwards, will probably get to the main floor manifold tomorrow. I have a question about purging air out of the lines. When I connect the domestic water to the primary loop boiler drain to fill the primary loop it seems like I keep getting big air bubbles in my 5gal. bucket even after dumping 8 or 10 buckets. Is this normal or could I be getting air in my water from my well pump?

jonny88

I unfortunatly have installed a few Naviens.They sell a premade primary loop with unions which attach to the boiler.Even webstone advertised on this site sell it.Takes out the guesswork .By the way in a few months your will never be able to see your balancing valves,they are looking a little dirty right now.Good catch guys with the manifold.With all the black pipe I would recommend a caleffi dirt seperator.Good luck

icesailor

SoundPipes said:

I am considering putting the Grundfos circulator in my primary loop on the return side. Would this improve the flow through the boiler and keep it the water from flashing to steam and shutting down. I do think I have a greater flow in my secondary loops compared to my primary loop and am loosing most of my heated water to a reverse flow between the closely spaced tee's. Any ideas.

Thank you.

Aren't you supposed to have a primary pump on the return, pumping primary water into and through the boiler? And not depending on the secondary pumps to pump primary water through the boiler?

Where IS the primary pump?

icesailor

"" When I connect the domestic water to the primary loop boiler drain to fill the primary loop it seems like I keep getting big air bubbles in my 5gal. bucket even after dumping 8 or 10 buckets. Is this normal or could I be getting air in my water from my well 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.

Gordy

The primary pump is the on board pump. Look at the navien piping schematics. You will soon understand why you can only get so many btus out of that boiler.null

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

ToddAK

The Navien CH240 will run with zero flow in the secondary piping and not go to a fault 16 if the primary boiler pump is running and the filter on the boiler piping is not plugged. Verify your voltage to the pump is correct at the terminal board, you can also remove the screw from the pump and verify if its spinning. Bleed pressure off of the system and clean the filter on the boiler side. Also make sure that your did switches are set correctly for the temps you are running IE dip switch 8 high or low temp as you will be fighting your setting verses what the computer will allow. If you have it set to high temp make sure your flue is correct. If the output domestic is not connected yet make sure have water still in the domestic side by bleeding it also as it will prioritize to domestic and an air bubble will not read water temps correctly. Start with the basics.

Gordy

I was going to mention dip switch settings but figured installer did that .....now not so sure

SoundPipes

I will check my Dip switch settings again. I believe they match up to the way it is installed. I have cleaned out the filter a few times in the past , but will check again. When I first try to start the boiler after purging and filling the lines. There is always a gurgling or slushing sound when the Navien kicks on and some knocking . I think it must be air, but I can't seem to get all of the air out of the system. I use the top plastic bleeder and the round brass bleeder inside the system to try to get the air, but it almost always flashes to steam and shuts off. My installer got me a new Navien pump which was just installed a few weeks ago, so I am pretty sure it is running fine, but will double check the voltage.

Gordy

How are you doing your complete "system" purging procedure?
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.

SoundPipes

Do you know where the Automatic Flow adjustment valve is? When I first turned it back on after making the suggested changes and checks, this time I got error code E01 (Water is boiling in the heat exchanger). I have checked and cleaned the filters, they are fine. One of the other recommendations is to adjust the automatic flow valve. I can't seem to find this part in the installation manual parts breakdown. Does anyone know where to find this? The navien ran okay for about 5 minutes before overheating, flashing the water to steam and throwing error code E016.

SoundPipes

I was first trying to purge the air with a small pump, so I could keep everything in a bucket. That didn't seem to work so switched to a hose connected to the basement sink, lots more power. Although when I purge the 6 upstairs loops and isolate one loop at a time, I probably run 5 - 10 gallons through a single loop and still get large air bubbles coming into the bucket. Does this make any sense? Thanks for all of your help.

Gordy

Keep power purging until no bubbles even little ones.

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?

SoundPipes

Hey Gordy, I just finished purging all loops, secondary lines and primary loop. I finally got down to zero bubbles and good flow. I have switched the manifolds, rotated the motors, removed the bypass, checked dip switches, checked and clean filters, so I thought it would be a good time to fire up the Navien again. It starts up and the primary loop starts to get warm, but after a minute or two, I hear a gurgling sound in the heat exchanger of the boiler, I try to bleed off any air, but it quickly ramps up to 220+ degrees and this time through out Navien error code 001 (water boiling in heat exchanger). Do you think I have a faulty heat exchanger or clogged or something?

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?

Gordy

Did you purge the DHW side ? Even though it's not hooked up need to purge it.

SoundPipes

No I did not, should I just open the hot side into a bucket? If I ever get this thing working, I hope to hook up the hot water and maybe that will work.

SoundPipes

Do you know where to find or adjust the automatic flow valve in the Navien unit? It lists that as one of the things to check when getting error codes.