Replacing Noritz NRC1111-DVNG 11GPM with Commercial Noritz or Navien

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Lifespeed

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I have a Noritz NRC1111-DVNG installed in the attic when I re-piped the house in 2012. 10 months ago the lower copper heat exchanger started leaking, so I hired a local tankless specialist to replace it along with the gas manifold and some associated parts provided under warranty by Noritz. Not even a year later, the stainless upper heat exchanger started leaking at the in/out copper pipe fittings, and it looks as though the exchanger itself may be leaking as well. I almost considered repairing it once more, but the water heater guy wants $800 on top of the warrantied parts from Noritz. I don't think it's wise to continue dumping money in this thing.

A different local installer tells me Navien is reliable, and to only buy a heater with an all-stainless heat exchanger. He thinks Navien is more reliable than Noritz, although this is probably based on the mixed copper/stainless dual exchanger models. So here are two models I'm considering, and some thoughts. Please share your experiences.

Navien NPE-240S2 $1,550
Recommended by local installer
reliable stainless heat exchanger
appears to be "consumer" grade, whatever that means
supports remote interface

Noritz NCC199CDV $2,550
dual stainless heat exchangers, constructed as one piece. Looks like they took reliability to heart, here.
"commercial" grade
Unknown if remote interface is supported, already have one installed so this could be free

Obviously there is a big price difference. Does the "commercial" Noritz buy better and longer reliability? It's worth alot not to have to replace heat exchangers midway through the water heater's life cycle, not to mention the many other components that can fail.
 

WorthFlorida

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I have no experience with tankless systems, but a life time of reading "commercial grade" means to be wary. There are no official definitions of what commercial use means.
 

Fitter30

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Like to know if the yearly maintenance was done to the leaking heater including running vinegar through it?
A mineral coating is detrimental to the life of the heat exchanger. First it creates hot spots in the exchanger which weakens it and creates cracking and if its bad enough the water will boil in it. Commercial ,residential or brand doesn't matter.
 

John Gayewski

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Sounds like your water quality is bad for hot water.

We only install Navien. They are pretty good and have very hearty heat exchangers.

No matter which one you get it needs to be serviced every year, and every six months in certain circumstances. Tankless has its downsides.
 

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We only install Navien (like JG above) and love the all S.S. heat exchanger. That more as a choice to concentrate and specialize in one brand. Noritz makes great products but you must have a water quality problem. Maybe you need a water treatment solution!?
Clear downsides for Navien:
1. The excellent tech 800 troubleshooting phone resource doesn't much want to talk with homeowners b/c it is a time suck.
2. If you are using the NPE A2 series and utilizing recirculation, they have a check valve failure issue. The check valves are homeowner-easy to replace, but after 6 years of free warranty replacements, at least in our N. CA EBMUD water district, the chloramine disenfectant guarantees that the o-ring in the check valve will deteriorate and require swapping out at your expense for years to come. (under $20. but annoying an negligent on Navien's part.) This has been going on for over a decade already. Steady work for a plumber, but a real failure nevertheless.
 

Lifespeed

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Like to know if the yearly maintenance was done to the leaking heater including running vinegar through it?
A mineral coating is detrimental to the life of the heat exchanger. First it creates hot spots in the exchanger which weakens it and creates cracking and if its bad enough the water will boil in it. Commercial ,residential or brand doesn't matter.
The heater only saw softened water with the chloramine removed by a backwashing catalytic carbon filter, and was flushed with vinegar every year. It wasn't negligent maintenance, it was a Noritz problem.
 

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We only install Navien (like JG above) and love the all S.S. heat exchanger. That more as a choice to concentrate and specialize in one brand. Noritz makes great products but you must have a water quality problem. Maybe you need a water treatment solution!?
Clear downsides for Navien:
1. The excellent tech 800 troubleshooting phone resource doesn't much want to talk with homeowners b/c it is a time suck.
2. If you are using the NPE A2 series and utilizing recirculation, they have a check valve failure issue. The check valves are homeowner-easy to replace, but after 6 years of free warranty replacements, at least in our N. CA EBMUD water district, the chloramine disenfectant guarantees that the o-ring in the check valve will deteriorate and require swapping out at your expense for years to come. (under $20. but annoying an negligent on Navien's part.) This has been going on for over a decade already. Steady work for a plumber, but a real failure nevertheless.
Unfortunate about support not talking to homeowners, Noritz was good about that. I have a recirculation pump and check valve installed external to the water heater, so would want the NPE-240S2 model without recirc.
 

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The things about the Navien A series is the aquastat that turns off the pump and cycles at intervals to save un-needed run time, the parameters to choose various elements on recirc. That all affects the excellent tunability which you don't get with an external pump.
With a full on external pump, you loose efficiency.
 

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The things about the Navien A series is the aquastat that turns off the pump and cycles at intervals to save un-needed run time, the parameters to choose various elements on recirc. That all affects the excellent tunability which you don't get with an external pump.
With a full on external pump, you loose efficiency.
You're making assumptions about my recirculation setup. It is controlled by home automation and an aquastat. It works perfectly, only running when needed.
 

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Bought a Navien NPE-240S2. Mounting and venting now, plumber will come tomorrow to sweat the copper and move the gas pipe an inch or two.
 
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Willing To Learn

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We only install Navien (like JG above) and love the all S.S. heat exchanger. That more as a choice to concentrate and specialize in one brand. Noritz makes great products but you must have a water quality problem. Maybe you need a water treatment solution!?
Clear downsides for Navien:
1. The excellent tech 800 troubleshooting phone resource doesn't much want to talk with homeowners b/c it is a time suck.
2. If you are using the NPE A2 series and utilizing recirculation, they have a check valve failure issue. The check valves are homeowner-easy to replace, but after 6 years of free warranty replacements, at least in our N. CA EBMUD water district, the chloramine disenfectant guarantees that the o-ring in the check valve will deteriorate and require swapping out at your expense for years to come. (under $20. but annoying an negligent on Navien's part.) This has been going on for over a decade already. Steady work for a plumber, but a real failure nevertheless.
I've determined the Navien NPE-210 is the size unit needed, just not sure which model, A2 or S2. We get hot water in 30-40 seconds at the faucet furthest from the current "tank" water heater. Not sure of the demand heater without recirculation (S2) will decrease, increase or maintain that time delay. After reading about the check valve failure, I'm leaning towards the S2 model to avoid that issue.

Also, can I calculate the time delay to get hot water with the NPE-210-S2 based on our current 30-40 seconds. Is the valve failure issue worth going to the A2? Our water has chloramine too.
 

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The A2 version's pump and mini-tank make it so that water is hot and doesn't have to course through the heater, so the A2 is the match to the current time delay if the distance matches.
The A2 is the way to go. Chloramine is an issue only on the internal check valve and is very easy to replace. Off the top of my head, if you don't have dedicated recirculation, the check valve may not have a function at all.
 

Willing To Learn

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The A2 version's pump and mini-tank make it so that water is hot and doesn't have to course through the heater, so the A2 is the match to the current time delay if the distance matches.
The A2 is the way to go. Chloramine is an issue only on the internal check valve and is very easy to replace. Off the top of my head, if you don't have dedicated recirculation, the check valve may not have a function at all.
Thank you. I know the A2 has a 2-gallon tank that keeps water hot for quicker access and runs when the temp differential drops in the tank based on the system temp setting. There is no way to change that. Just not sure the differential between the A2 and S2 in purchase, fuel and check valve cost plus the failure issues, is worth it. I understand there is water loss without the recirculation but if I can get water within 20-30 seconds of our current install which is 40 seconds, I'm satisfied. It's a pretty short run from the water heater already. I can replace the check valve but it's yet another maintenance issue on the list in addition to flushing the system.

Navien's website does state that the NaviCirc valve is designed for applications where there is not a dedicated recirculation line.
Just watched the animation of how the valve works... the valve can be used on the A2 and S2 models. It's only function is to divert cold water in the hot supply line over to the cold line until it is up to temperature. At that point, the valve opens allowing hot water to the faucet. Although I don't evade the valve failure issue, I can spend less purchasing the S2. Thanks for the discussion and your input.

 
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GReynolds929

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The A2 with recirculation enabled, even if it's internal recirc eliminates any minimum flow requirements. If you're going to recirc, even with navicirc the A2 is the one to get. With the S2 you would still need an additional pump, check valve and piping. Like @Breplum said the check valve is easy to replace if it fails, and cheap if after the warranty runs out. It would not deter me in getting an A2. We only install A2 units in my area, even if no external recirculation is used.
 

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The buffer tank is .5 G and serves its purpose wonderfully. NaviCirc only works with A series. We only install A2, also
 

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I see I didn't post photos of my finished Navien NPE-240S2 installation, her are some belated pics.

Old Noritz NRC1111-DVNG:
20230923_115037_1280.jpg
20230923_115100_1280.jpg


And here is the new Navien S2 with dedicated external recirc controlled by home automation. Note the 12-year-old Taco pump and bronze, external check valve are still going strong while the old Noritz leaked it's way to replacement.
20230926_173821_1280.jpg


Note the expensive, new bronze check valve in the cold water inlet.
20230925_205320_1280.jpg


As far as whether to by the recirc or non-recirc Navien, I would say if you don't already have a proper recirc installed it is much easier and cheaper to use the recirc version. Still, I would consider running a dedicated return line a strong want.

If you've already get a proper recirc setup with aquastat and safety and efficiency features like run time limit, scheduling, etc, then I see no advantage to combining the water heater with recirc. There is no advantage to an internal tank in my plumbing, the 1" insulated trunk pipe serves that purpose just fine. In my case the time-tested pump, check valve and controller have acquitted themselves well and are on their 12th year, and are independently serviceable from the water heater. I did install a new check valve with the new copper inlet pipe, no point to try and salvage the old one.

I have no doubt the experienced plumbers here encounter far more incorrect recirculation setups than correct ones, hence the Navien A2 recommends.
 
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GReynolds929

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Glad it's working for you. Just fyi if that pump is not brass or stainless flange and body it's not allowed on potable systems. I'm assuming you have service valves since the old unit did and I just can't see them. I would have pulled combustion air from outside and not the dirty, dusty, insulation filled attic. Every plumber has their own way of doing things. Glad you're happy with yours.
 

Lifespeed

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Glad it's working for you. Just fyi if that pump is not brass or stainless flange and body it's not allowed on potable systems. I'm assuming you have service valves since the old unit did and I just can't see them. I would have pulled combustion air from outside and not the dirty, dusty, insulation filled attic. Every plumber has their own way of doing things. Glad you're happy with yours.
You can't see the stainless pump body in the photo? The venting is a quick install to get hot showers while I wait for the roofer to come out and replace the roof jack to fit the PVC concentric vent. What a bunch of critics :rolleyes:

20230923_115100.jpg
 
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Willing To Learn

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The A2 with recirculation enabled, even if it's internal recirc eliminates any minimum flow requirements. If you're going to recirc, even with navicirc the A2 is the one to get. With the S2 you would still need an additional pump, check valve and piping. Like @Breplum said the check valve is easy to replace if it fails, and cheap if after the warranty runs out. It would not deter me in getting an A2. We only install A2 units in my area, even if no external recirculation is used.
Thanks. I wondered if I would need an external pump for the recirculation on the S2. Waiting to hear from Navien as their video and installation manual both indicate you can install NaviCirc with the A, A2 and the S2 models. They only show an external pump install on of you have the Hot Button. If I have to get an external pump, might as well go with the A2. Also the NaviCirc is now listed as a 3 year warranty.
 
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