I guess there’s a reason why plumbers can charge so much...

CoryH

I’ve throttled my loop valves down again in an effort to slow the flow rate. I played with them a bit until I think I got the flow rate pretty close to that of the boiler/primary circulator. I think I’ve achieved this because the top half of my common pipe is blazing hot and the bottom half is cool, indicates to me that there is close to neutral flow through it. Going to let it sit this way for the night and see what I wake up to. I imagine it will take some time to cycle all of the cold water out of the radiators with this much slower flow rate. Anyone have any thoughts on this?

mattmia2

It this is natural gas, look at the diagnostic dial on the meter (the quarter, half 1, 2 ft dial) and time how long it takes to make a revolution and use this table to figure out how much gas it is consuming. It it isn't consuming about 50 ft^3/hr or more with the primary and secondary pumps running and the heating loops not getting above warm, there is a circulation issue in the boiler loop.

https://www.aprsupply.com/ASSETS/DOCUMENTS/CMS/EN/Tech_Support_PDFs/Checking Firing Rate.pdf

CoryH

@mattmia2 immon tanks that, as far as I know, only have TLI’s, no meters.

Gordy

The three way valve is fine.

There are three scenarios in primary secondary flow rates. Same applies if using a hydraulic separator.

Primary, and secondary have equal flow rates.
Primary flow rate is greater than secondary.
Primary flow rate is less than secondary.

In the above there’s is an infinite mix temp, and flow rate possibility in the greater than, and less than scenarios.


Your onboard pump is going to be 4.5 to 5 gpm that’s it, and no getting around that.

The only way to know what your heating loops are flowing is to use the pump size, and equivalent length of pipe to determine head loss at the required flow rate. Then you read the pump curve chart to determine the flow rate of each zone.

With all that said I believe your heating circuit flow rate is a lot more than your boiler circuit. Especially evident if the boiler never stops running. So it’s not shutting down on high limit, and it’s not shutting down on room set point.

The only thing we don’t know is what the modulation is. Is it always 100%? I’m inclined to think so.

I’m also think that your gas supply is sufficient since you have no problem with the DHW. At least that is what you eluded to.

DanInNaperville

CoryH said:

I’ve throttled my loop valves down again in an effort to slow the flow rate. I played with them a bit until I think I got the flow rate pretty close to that of the boiler/primary circulator. I think I’ve achieved this because the top half of my common pipe is blazing hot and the bottom half is cool, indicates to me that there is close to neutral flow through it. Going to let it sit this way for the night and see what I wake up to. I imagine it will take some time to cycle all of the cold water out of the radiators with this much slower flow rate. Anyone have any thoughts on this?

I don't think that's right. The whole point of a hydronic separator (which is what the primary loop is functioning as) is to allow for different rates of flow in the two loops. Trying to make them the same is wrong - if you're going to do that, there's no point in having a primary and a secondary.

You're not getting sufficient flow through the primary loop. A condensing boiler ideally runs fairly cool to maximize condensation. The volume of cool water coming into the boiler will produce the most efficiency when the supply coming out of the boiler is at the lowest temperature (not 180 degrees).
To maintain 180 degrees when flowing 4 gallons per minute when the return water is "cool" (100 degrees?) would require the full output of your 180K BTU boiler, and the water going out of it to heat the house would be making your supply pipes and radiators 180 degrees in a few minutes. If the boiler is designed to throttle down for CH, it would be even less capable of maintaining 180 degrees out at 4 gallons per minute flow. Given that we aren't in the middle of a polar vortex, if you were sending 95% of 100k BTUs into your house right now it would feel like an oven.
The heat isn't getting out of your boiler, which means the valve is closed or the pump isn't working. Since DHW depends on the same pump, the valve seems to be closed (for CH).
It's either a problem with the valve, an issue with the control board, or some input into the control board (setting or sensor).
You could try disconnecting the water flow sensor that triggers DHW mode and see if that releases the 3 way valve.

DanInNaperville

CoryH said:

I’ve throttled my loop valves down again in an effort to slow the flow rate. I played with them a bit until I think I got the flow rate pretty close to that of the boiler/primary circulator. Anyone have any thoughts on this?

Don't do that.
Blocking flow too much can cause the pump to cavitate and be air locked, and that can cause it to burn out.
The whole point of a primary and secondary loop is to allow for different flow rates in the two loops. In the case of a condensing boiler like yours, that typically has small water passages, you need to be able to maintain enough pressure differential to generate enough flow through the heat exchanger to keep it from overheating and being damaged. Minimum flow must be maintained. In the case of a cast iron boiler, it's the opposite, where you need to keep the flow low enough to prevent the boiler from being cooled too much by the return flow and condensing (the opposite of what you're trying to do with a mod/con boiler like yours) because cast iron boilers rust if they condense for long periods of time.
Either way, the whole point of plumbing in a primary loop is to allow for different rates of flow in the primary and secondary loops. It's not only unnecessary to try to match the flow, it defeats the whole point of having two loops.

mattmia2

In the parts list it shows an item 40 "heating return block filter". Did you make sure that is clear?

http://support.noritz.com/download.php?file=Literature Page/Parts List/Combi Boiler PART.pdf&field=PartsList

SuperJ

Agree with checking the filter. If the pump is before the filter, it's pretty straightforward to pull the head off the pump and check if you have junk stuck in your impeller. Just 4 allen bolts.

Also, with the temps you require you should have CPVC exhaust venting. Your boiler will throttle and shutoff if the exhaust temp goes above about 149F, this jumps to 200F when configured for CPVC. Please don't switch you boiler setting without changing the vent material first though.

DanInNaperville

Check the filter - @mattmia2 made a great point. Do that before screwing with the 3 way valve.
Lots of pipe dope in the loops and and a screen filter in the return - I'll bet that's it.

Gordy

You can check the filters easily.

mattmia2

You might need to use some paint thinner or something like that if you got dope in there.

CoryH

Just checked the filters, they look brand new, nothing in them. But I’m not surprised because of the flow rate difference, any debris seems like it would flow right by the primary suction and continue back through the secondary.

CoryH

I keep telling you guys, the thing makes hot water like a SOB. The primary discharge is blazing hot, and immediately.

I opened the valves that I had throttled back at 2:30 this morning because the hot water seemed to not be going any farther through the loops, so to not burn out a pump I erred on caution. I will pull the pump head on Thursday to check that.

Tom_133

Cory,

Have you tried starting your smallest zone only with your new configuration? 30 seconds seems like a LONG time to get the primary loop hot if no other zone is running. I would suggest if the filters are not plugged something else may be stuck in that primary piping. Or that primary pump is not running properly. I have never installed a Noritz, but in other style combo's the pump is not in use during hot water production hence you getting a ton of it. As soon as the system kicks over to using the pump and Central heating it struggles. Does the display on a noritz show GPM when running?

Gordy

Yes @CoryH , I know that your dhw output is fine from previous posts.

@CoryH , what are your system zone pump sizes? I see they are taco. 007?
Then give me approximately how many feet of piping in that complete zone loop. So from the supply manifold to the return manifold including baseboard footage. You can do the longest one is all.

I’ll give you a ball park idea how many gpm a zone is moving.

Come on fellas. If there is that much restricted flow, or if the boiler pump is not working the boiler would shutting down on HL.......

ch4man

CoryH said:

I’ve throttled my loop valves down again in an effort to slow the flow rate. I played with them a bit until I think I got the flow rate pretty close to that of the boiler/primary circulator. I think I’ve achieved this because the top half of my common pipe is blazing hot and the bottom half is cool, indicates to me that there is close to neutral flow through it. Going to let it sit this way for the night and see what I wake up to. I imagine it will take some time to cycle all of the cold water out of the radiators with this much slower flow rate. Anyone have any thoughts on this?

to further muddy the waters, its been my experience that when the common pipe it hot on top and cool on the bottom the flow in the common pipe is flowing "backwards". this happen when the boiler circ is working but the house loop flow is poor or non existent . what goes into a T must come out of a T. a bit is ok for temperature control but a lot is bad.

this is harsh, but you have a new reliable boiler/water heater but clearly a poorly designed and installed piping system and near boiler piping. applying the KISS principle dictates you need a pro onsite, in your basement with you upstairs out of the way to rip it all out and start over without distraction.
sorry, i warned you it was harsh but social media is not always the answer. this is a great site and has helped many a homeowner and pro alike, but i think yours is beyond that

Gordy

If you read all his posts you’ll know why he’s trying to do this on his own. Everyone has bad luck at some point in their life. Let’s try to help him out as best we can with in safe parameters through this site. It is called Heating Help.com .... not find a pro.com.

hot_rod

Gordy said:

If you read all his posts you’ll know why he’s trying to do this on his own. Everyone has bad luck at some point in their life. Let’s try to help him out as best we can with in safe parameters through this site. It is called Heating Help.com .... not find a pro.com.

Looks to me like every post has ben polite and helpful.

The data just doesn't add up.

Boiler comes up to temperature and shuts down, no lockouts?
Double checked 11K heatloss?
67' of fin tube? 5- 3/4 zones?
Piping correct to manual and acceptable piping guidelines
1" piping able to carry the boilers 40K output
Doesn't transfer heat with even 1 zone calling?

It could be time for a 1 hour service call from a Noritz experienced contractor.
A combustion analysis would be a good idea also, and experienced contractor could supply that check also.

Gordy

I wasn’t referring to everyone.

SuperJ

CoryH said:

I keep telling you guys, the thing makes hot water like a SOB. The primary discharge is blazing hot, and immediately.

If you have low flow the boiler should still make heat but it will throttle sooner since it takes less btu's to heat a lower flow rate. High temps can be an indicator of low flow if they aren't propagating out as expected.

Have you opened the internal air purge valve?
Do you have any air purge valves higher in the house?
Have you tried running each zone individually to see if they all behave the same?

We need some real measurements while running steady state. (not just it feels hot). Temperature readings can help to give an idea of what the flow is doing.
-Boiler In and Out (primary temperatures, these may be visible on the boiler screen).
-Zone supply and return temperatures (with a single and multiple zones calling).

If using an IR thermometer you may have have to put some opaque tape on the pipe for it to read accurately. Take your secondary temperature readings on the black pipe (not the pex).

Can you take some more pictures of your system, from a variety of angles with wide angles and closeups. There may be something that jumps out as a problem.

bob eck

If you go on Lochinvar University they have a calculator where you can put info in and if the secondary pumps are flowing less GPM than the primary pump GPM you get reverse flow and the system will never heat.
Secondary pumps need to flow more GPM than the primary pump GPM.
What boiler is installed and what GPM is needed to go through that heat exchanger?
Is it a combi boiler with internal pump?
Is it a condensing heating boiler with pump outside of the boiler? If so in the pump installed in the correct location?
If pump is outside the boiler is the pump sized correctly?

DanInNaperville

I think it's time to go back to the 3-way valve.
If the supply temp sensor is bad, the boiler could think that the water it's supplying is too cool. Try setting it for low mass radiant floor instead of baseboard so that it's willing to allow full flow at a lower supply temperature. If that doesn't make any difference, put it back to the original setting and then go after the 3 way valve.

Disconnect the supply and return lines and connect the return to a hose and point the supply at a bucket. Turn on the water to the see what kind of flow you get.
If the valve defaults to DHW instead of CH, you may have to jumper a couple of the connections on the valve, but since it's supposed to react to sensing flow, I would guess that the default is CH.

hcpatel78

CORYH ' please call tech support of Noritz.... you don't believe that will solve your issue in one call. Ask to guide through to set up the controller of your boiler.... I read the whole conversation...none of the time you mentioned that you talked to Noritz or not....
I am really interested to hear the solution as I am in the process of the design and install radiant heat for my house located in northern NJ with Noritz combi boiler CB199DV-NG (Natural Gas)...
One gentleman here posted the nice picture for their setup..please see attached.. I am posting again here. You might will get some idea of piping....

hcpatel78

BAck flow preventer?

STEVEusaPA

Why don't you hire one of the experts from this site (or any hydronics pro, not necessarily just a plumber) to come over to your house, sort all of this out, so you get on with your life. You appear to have a wife and 2 kids...they probably want their old dad back.

It's too painful to watch you try to get this working.
Where are you located?

Jellis

I believe your not so closely spaced Tee under the boiler may be causing the issue.
based on your "hot and cold" diagram i believe too much flow is coming from your return and not enough is flowing through your boiler.

I would certainly move those closer together and see how that works.
move pumps to the supply and pumping away from expansion and i think you will be good to go!

hcpatel78

Just copy that exact dimensions from the Manifold Kit sold by Noritz for the closed spaced TEE spec...

DanInNaperville

@CoryH - can you clarify whether the pipe returning water from the primary loop is cool? You seem to have implied that, but have not been explicit. Assuming that it is, then you don't have some subtle flow issue. The return line is cool. Heat is not leaving the boiler. It isn't trapped in the primary and flowing back into the boiler - the return is cool, so that's not what's happening.
The supply line is hot where it's connected to the boiler, and close to it in the primary loop, so the boiler is firing, but very little is flowing into the primary loop - the secondary loop doesn't really matter at this point. Either the 3 way valve isn't sending water to the primary loop or the internal pump isn't running in CH mode and that's why almost nothing is getting out of the boiler.
I think you got a boiler with a bad part. It happens with all products once in a while.
That Noritz doesn't include a full circuit diagram in its service manual is pathetic. It turns what should have been no more than an annoyance into a nightmare.

hot_rod

Jellis said:

I believe your not so closely spaced Tee under the boiler may be causing the issue.
based on your "hot and cold" diagram i believe too much flow is coming from your return and not enough is flowing through your boiler.

I would certainly move those closer together and see how that works.
move pumps to the supply and pumping away from expansion and i think you will be good to go!

The space between the tees is all about the pressure drop in that section of piping. As the space increases pressure drop increases and can push some flow up and back the branches when the secondary circulators operate. In this case that might be a good thing

Those tees could be 3 feet apart and the boiler loop would flow just fine.

With that high pressure drop boiler, I doubt the zone circulators would see enough resistance between the tees would induce any flow, even at 3 feet of space between.

Similar concept with monoflo tees, the more resistance in the run, the more flow potential out the branch.

Gordy

IF the boiler is at 100% modulation then where are all the 90k of btus going🤔

Even if it’s modulating down to 50%.

Something has to give.....

mattmia2

Here's another stupid question, and I think I know the answer since it is making DHW, but is the cap on the air eliminator inside the boiler loose so it is able to vent air out of the internal piping in the boiler?

mattmia2

It looks like there is a "DHW preheat" function that maybe locks out heating when it is active.

I assume you tried a factory reset and resetting the parameters in case something in the firmware got screwed up. My HTP UFT got screwed up in some way when I was purging with the boiler off but powered on such that it wouldn't generate a DHW call. I had to factory reset it to get it working right again.

Gordy

Look at the chart for the pump curve I posted.

If you size a circulator properly, you try for it to fall in the middle, or upper 1/3 of the pump curve. Sometimes that is not always possible.

Supposedly it’s a three speed circ. The chart doesn’t indicate a speed for the curve. I would assume speed 3.

Is the primary really seeing 4.5 gpm?

CoryH

Had work overnight last night, so i'm going to try to get through all of these...

@Gordy , It is a 3 speed circ, but I have no way of actually measuring gpm's…

@mattmia2 , reset done with no changes. The pre-heat option is turned off. Also, the vent cap for both the internal air scoop and the vent on the circ pump are open, and venting.

@STEVEusaPA , trust me, i'm almost there...haha this thing is killing me...

@DanInNaperville , I was scratching my head and talking with some guys at work about this (they have experience in pumping systems, just not residential heating systems) and after compiling all of the data that I've gotton from doing all the stuff everyone has mentioned, the only logical remaining item is the 3-way valve or the pump. When I get home tonight i'm going to pull them both and see what I can see. If I cant find anything, i'm throwing in the towel and getting a pro out here. Theres too much work left to do in this house that I actually CAN do that isn't getting done because i'm so focused on this.


@Tom_133 , I have tried the single loop, no go. I'm going to pull the 3-way and possibly the pump and go from there.

Thanks all

Ironman

@CoryH
You're gonna beat this issue whatever it may be. Just keep pressing on.

There's been a lot of advice offered here, most all of which is very good. The problem is when it comes from so many different sources, it's not systematic and every time one of us posts a different idea, it can throw you off track from the previous one you were persuing.

Let me reiterate one of the easiest and most basic suggestions and that's air binding. IDK exactly how you're attempting to purge the air because I'm not there, but if you're doing it at the bleeder on the BBs, just because you get water there doesn't prove that there's not air in the loop.

The proper way to do it is with a shut off and boiler drain valve at the end of each loop. You should temporarily increase the static fill valve pressure to 25 psi with the boiler off. Count the number of turns you turn the adjustment screw so you can reverse it when finished. Then, close all of the loop isolation valves. With a hose on the afore mentioned boiler drain and the shut off closed, open the shutoff valve on the other end of the loop and allow water to be pushed from the system fill, through the loop and out off the open drain valve on the other end. Once it's been bled for at least a couple minutes and there's no air coming out of the hose, shut both valves and the drain off and move to the next loop and repeat. And so on for each. It's important to make sure that every other loop is closed off except the one you're bleeding so you don't push air from one into the others.

But again, the loop that you're bleeding should only be opened to the system from the opposite end that the drain is on. You simply wanna push water from one side, through the loop and out of the drain.

The bleeders on the BBs can be used to remove small amounts of air after the loops have been purged as described above.

After you're finished purging, adjusted the fill valve back down to 15 psi. You may have to let some pressure off the system through a drain to do this.

Gordy

Another thing that @SuperJ pointed out earlier is changing the venting to cpvc. You most likely will never get 180 out of the boiler with out changing it out, and then changing the vent setting.

Gordy

Before you tear into the boiler components, It’s not going to hurt to call Noritz tech support either. It’s free.
Could be a problem that’s common, and they can walk you through it.

CoryH

So I’m on hold with Noritz as I type this. I start re-reading these comments and I get to the one where someone asked what the parameters on the panel are reading. I tell myself that you haven’t really spent a lot of time looking at what the panel is telling you, pull out the manual and try to figure out what all of these menus mean. I’m going to punch myself, the first option, I thought, was just to choose between liters or gallons. But then I ask myself, what is it trying to measure? Low and behold it’s a flow rate meter and it reads zero. Every now and then it makes a noise and the meter jumps to 1gpm for a split second and then quickly drops back to zero. Obviously there’s either a blockage or a faulty meter reading but I’m going to guess it’s a blockage. The interior circulator is running. No flow. It’s the unit. Not my piping, at least not yet....

mattmia2

Looking at all the cryptic icons and using the manual to decipher them is a good idea too.

CoryH

Well, disregard, that’s a flow meter for the DHW...