Navien Tankless Water Heater Comments and questions

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WorldPeace

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Hi, Reach,

Sorry, I didn't know you responded. Otherwise, I would have responded back sooner!

Here is the picture.. The red circle is the size of what needs to be replaced. You notice it's behind a copper pipe..actually several pipes.

Any ideas?

How about a fairly close photo?

20151228_104624.jpg
 
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Reach4

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I was thinking you were just trying to remove a plug -- not a big assembly.

It looks like the pipe to the left of the red circle has unions.
 

WorldPeace

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Looks like a pain in the butt, huh? Kind of dreading doing it. The part to be replaced is a large water pressure vent that's just screwed on. But, I can't get my hands in a position to turn it.

The other way is to remove the bottom pump which is connected to this vent. To do this, I would have to remove the control board (located to the right, beyond the picture's boundary), unscrew a couple of unions, and take out a couple of other parts. Just so I can turn a simple vent by hand or wrench.

Evidently, this vent gets clogged with lime and needs to be cleaned periodically. I guess the manufacturer's designer didn't anticipate that some Americans would have a hard water supply.

Great design!


Hi, Reach,

Sorry, I didn't know you responded. Otherwise, I would have responded back sooner!

Here is the picture.. The red circle is the size of what needs to be replaced. You notice it's behind a copper pipe..actually several pipes.

Any ideas?
I was thinking you were just trying to remove a plug -- not a big assembly.

It looks like the pipe to the left of the red circle has unions.
 

QueBall

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There are two styles of recirculation pumps depending on the age of your unit.

Older Pump with black cap has a metal wire retention clip you pull out to release the air purge valve and it pulls straight out. Be careful as it's easy to damage the O ring when replacing it. I suggest having a replacement on hand. This is the one I have.

Pump with Red cap are newer. I'm not even sure if this model needs to be removed for cleaning.
 
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WorldPeace

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Hi, Queball,

Thanks for the reply.

I couldn't figure out how to take out the vent. I called customer service and they told me what to turn but still couldn't take it out. So, I had to take apart the board the entire pump. I realize now that I was turning the correct part but it's literally impossible to turn it when the threads are encrusted with minerals. It doesn't turn very well. So, in my case, you need to take it out and turn that middle part with your hand.

Right now, I can't seem to get the pump back in. I slide the pump back into that inlet pipe but it doesn't seem to form enough of a seal so that I can slide that metal U clip in. I'm trying to figure out what to do right now.


There are two styles of recirculation pumps depending on the age of your unit.

Older Pump with black cap has a metal wire retention clip you pull out to release the air purge valve and it pulls straight out. Be careful as it's easy to damage the O ring when replacing it. I suggest having a replacement on hand. This is the one I have.

Pump with Red cap are newer. I'm not even sure if this model needs to be removed for cleaning.
 
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Foolishtrader

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I have 6 year old Navien tankless water heater and am getting condensation on the "outside" of the black condensation collector at the bottom of the burner assembly, any ideas of the cause? It is slowly dripping out of the bottom of the unit. Could it be from check valve failure allowing cold water back through the recirculation line? I just ordered the check valves as my installer is not returning my calls. Any ideas would be great as the tech guys blew me off and no help from my installer need some place to start.
 

Bannerman

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Add a photo to this thread.

'Dripping out the bottom of the unit' requires a better definition. Perhaps a photo can show the specific location.

Photos need to be 800 pixels or less.
 

QueBall

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I have 6 year old Navien tankless water heater and am getting condensation on the "outside" of the black condensation collector at the bottom of the burner assembly, any ideas of the cause? It is slowly dripping out of the bottom of the unit. Could it be from check valve failure allowing cold water back through the recirculation line? I just ordered the check valves as my installer is not returning my calls. Any ideas would be great as the tech guys blew me off and no help from my installer need some place to start.

Maybe do a leak check on the heat exchanger. Get the soapy stuff and watch for bubbles. Obviously if this component has failed you should get your installer back in asap. That would be a potentially dangerous situation if combustion gas is leaking out. You want the authorized installer to verify it to qualify for the 12 year parts warranty if this is the case. You will have to pay the labour costs, but the parts costs if yours is installed properly, regularly flushed and serviced, and registered with Navien would be covered on the heat exchanger warranty.

Video I found someone doing a leak check:


(fast forward to 4:45 if the link doesn't start at that spot)

So I have heard of two things with the "condensation". One isn't water, it's a byproduct of the machining process of some kind of lubricant oil they use on the CNC machine during manufacturing that was not fully removed and it sweats out and never really dries since it's an oil. It's basically cosmetic. You could probably ignore.

The other is obviously real water condensation, it dries if you turn the heater off and needs to be investigated and fixed. The heat exchanger leaking is one potential source and probably the most serious case but there are less critical problems. Check the condensate trap for debris because if that clogs you can have condensate leaking around the bottom. So if your exhaust pipe is getting dirt, leaves, bird crap, etc it can dribble back down and clog up the condensate trap. If you have a roof exhaust the bird pooping in the pipe is pretty common. Just clean out that condensate trap under the unit a few times a year or more frequently if you are always dumping out clump of junk when you clean it. Usually mine is just a little layer of sediment like from dust until spring when the poplar tree seeds are heavy.

But you have a dozen other points with o-rings and seals inside where it might be coming from. The recirculation pump air purge valve has been known to get encrusted with minerals and then become stuck slightly open which can cause a slow drip. Older units may have the weaker version flow valves and air pressure sensors that were improved on in the next version. The air pressure sensor body tended to split along the seams of the two halves of the plastic allowing a small leak when they get old but that usually trips air pressure codes. The older all plastic water flow valves would wear out and if you had previously removed them to clean the "impeller" inside, the o-rings may not have seated properly when re-assembled.

As for internal valves, I have heard of the 3 way valve in recirculation A models having issues but not seen it so I do not know what the external symptoms of this might be. I think it might have been units set for internal circulation had the problem more than when set to external circulation but that is just a guess.
 

automaton

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I have 6 year old Navien tankless water heater and am getting condensation on the "outside" of the black condensation collector at the bottom of the burner assembly, any ideas of the cause? It is slowly dripping out of the bottom of the unit. Could it be from check valve failure allowing cold water back through the recirculation line? I just ordered the check valves as my installer is not returning my calls. Any ideas would be great as the tech guys blew me off and no help from my installer need some place to start.

@QueBall gave some good hints, second those, but I may have one more. Is the condensation oily? Maybe a bit brown? What does your venting look like on the outside? If you scour the web, you'll find some reports on this - exhaust suckback, where the exhaust is too close to the air intake. May require moving/extending the exhaust in that case.
 

bingow

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Hello, confused newbie here. I'm looking at buying a Navien NPN-199U and find zero references on NPN's in this forum. Is there something I'm missing? Likewise, there may be a smattering of info online about the NPE (condensing) models, but again almost nothing about non-condensing. Would appreciate any feedback from actual users of the NPN series, or those that would steer me away (for good reason, hopefully). My reason for wanting NPN vs NPE is cost/benefit for, say, the next 5-10 years, with the assumption that any reliability differences are minor. We will be replacing a 16 year old tank type that is still in good shape, but we want more space.

BTW, I am considering buying from a local plumber that has done excellent work for us in the past; he strongly recommends the Navien line, but I'm trying to get a fuller picture of the product. Thanks for any advice.
 

Bannerman

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A quality tankless water heater will often have a life expectancy approaching 25 years. A condensing unit will extract additional heat from the combustion gases, thereby increasing fuel efficiency and the supported hot water flow rate beyond that of a comparable capacity non-condensng unit. The difference in fuel consumption should be considered over 20-25 years. Compare also the suppirted GPM for your incoming water temp and your desired hot water temperature such as 120F.

A non-consenting will also require metal (often stainless steel) exhaust ducting vs plastic ducting typical for a condensing unit. A condensing unit may often allow greater mounting location options due to the cooler exhaust ducting which is often discharged through a distant sidewall.
 

bingow

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Thanks @Bannerman for the sales pitch, which I surely asked for. I am aware of the major advantages and disadvantages of the NPN vs NPE series, but I don't see the $ advantage for much shorter terms(which is my criteria) than 20-25 years. I'm just surprised at the dearth of user feedback, positive or negative, even if it's "Do not buy!" My guess is that for 5-10 years, we wouldn't notice much if any difference, except for an initial emptier pocket for the NPE.
 

Bannerman

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No sales pitch as I have nothing to gain regardless of what you buy.

Likely little/no mention of NPN as it seems most forum posters that own Navien, own NPE so maybe NPN does not have wide market acceptance?

What is the final cost difference including installation?

How many years to break even, assuming NG will not increase in cost over the next 5-10 years?

If you plan to sell the home in 5-10, will a condensing unit act as a sales feature?
 

bingow

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That could be: with Navien's so expensive, buyers who may initially be thinking of stepping down to the non-condensing series, then change to one of the other popular condensing brands at about the same price? I might do the same, although I was set on the stainless steel guts of the Navien. But the gained space is critical: we need it to replace our old, undersized salt-guzzling 30K grain water softener with a two-tank (resin+brine) 64K to 80K grain model. Our water hardness is 62 gpg. I'm watching another forum here for that....

I only have the written quote for the NPN-199u of $3,350 installed. The initial (verbal) quote for the NPE I do not recall, except that I immediately ruled it out. Maybe someone here has a current cost figure for the NPE-240, installed.

I think any functioning tankless heater would be a sales feature for a home in our market class.

Thanks again for your input.
 

Bannerman

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Maybe someone here has a current cost figure for the NPE-240, installed.
This being a DIY forum, prices are not usually discussed as prices can vary by area and also due to installation and material considerations unique to every installation.

I only have the written quote for the NPN-199u
Was that model recommended by the dealer, or only quoted at your request?
When you have no knowledge on the cost of an item, often the initial reaction of the first price is 'too much'. Since you can't remember, suggest obtaining further recommendations and quotes before deciding. Depending on number of bathrooms in your home and the temperature of your incoming water, perhaps a lower capacity unit will be satisfactory?

With regard to softener's, it sounds as though your current model is a 'cabinet' style that is too small so that it is regenerating frequently and likely not programmed for efficient operation. A softener with a single resin tank is a single tank unit, even as the brine tank is separate.

With such high raw water hardness, with the added concern about salt efficiency, you may want to consider/compare an alternating twin tank softener since a reserve allowance will not be needed but is required with a single tank unit. Once you are ready, you can ask about the benefits of each type in the Water Softener forum.

Was water hardness measured at your location, or was that amount stated by your water supplier? When municipal supplied water is obtained from multiple sources, the supplier will typically state an average hardness amount throughout the system, not the actual hardness supplied to your locatiin. The water arriving to your home could be higher or lower than average.

If your water source is your own private well, there is often additional metals and minerals in the water which also consume softening capacity beyond hardness. If so, those need to be also considered when sizing and programming a softener.
 
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bingow

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Quite a bit different from the Subaru Forester owner's forum, where $ are discussed routinely, with locale included, an educational bonus. Sorry, I confess I did not see that rule.

NPE-240 was suggested by our one and only plumber; we discussed; verified, and agreed 199k btu was the best size. 180k was marginal. I asked for and got the NPN quote, and now it's decision time.

Softener: yep, by two tanks I meant two tanks, not three with twin resins plus brine. We barely have room for the existing tank water heater and the cabinet softener. By going to a compact tankless water heater, we would have space for a 12" diameter 64k-80k resin tank, and a 18"x33" brine tank, with a little more room left over than what we now have. I'll DIY the softer installation. Wife & I built the house 21 years ago, took 6 years, did everything including electrical and PEX plumbing, excluding only the concrete slab and all nat'l gas work. I would have had to get a contractor's license to do the gas; no thanks. Thus, I'm having to deal with a plumber. We DIY everything else.

Water hardness done recently by specialty lab, negligible metals. Yes, private well on 3 acres, 7k elev.
 
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