Navien Combi Boilers

MacPHJr

Anyone have any experience with these units. I'm looking into it for a customer. The price along with the mass rebate and tax credit make it very appealing.

Dabbler

heat load

How do you figure a heating capacity of a Navien combi unit listed at 199,000

Dabbler

heat load

How do you figure a heating capacity of a Navien combi unit listed at 199,000

CMadatMe

IT IS NOT A BOILER

Will not qualify for 90% or 96% heating rebate. It is not a boiler, not rated as a boiler nor has the ratings for a boiler period!!!!!! Has no AHRI number. IT IS A TANKLESS WATER HEATER THAT IS PROMOTED AS A HEAT SOURCE!

EddieG

Installing....

I will be installing my first Combi version of the Navien, next week hopefully. We are in LP country and they just became available recently. I am waiting for the local rep. to get them in stock. I am personally partial to boilers for heating and water heaters for heating domestic. However this particular job the homeowner wanted to install a tank-less water heater and wants the ability to add a small radiant zone in the near future, so this seemed to be the perfect application for this.



Triangle Tube also now has the Challenger model available. We had a demo of it in our area last week. It's domestic output is slightly lower than other tank-less units, but you can use a buffer. If the existing water heater is in good shape, bingo, you have a buffer. I think it will work well for apartments and condos with smaller loads.  

HDE

?

Chris

Bad info, first, AHRI is a testing institute, not a government agency.

The combi is listed and recognized by DOE and Energy Star.

It is not a tankless, but a 2-circuit combi boiler, isolated with a heat exchanger

They also have a ASME H stamp boiler model, so if thats not a boiler, not sure what you think is?????????????????????????????????

CMadatMe

Orange Box Employee

Please tell us where in this installation manual that it states this is a boiler?



http://www.navienamerica.com/PDS/ftp/CombiGasWaterHeaters/Installation_Manual/CombiBoiler(CH)_Installation.pdf



Please show us where it states here other then the file name..



http://www.navienamerica.com/PDS/ftp/CombiGasWaterHeaters/Brochure/Navien_condensing_combi_boiler_091103.pdf

HDE

.

I understand your innocence and lack of information regarding combis. You see once you may have the opportunity to see the world you will understand that overseas they are called heaters since a real combi is dual purpose, separated circuits. Take for instance the embassy onyx, marketed as a boiler as itself and under other US boiler brand labels but, once you look at thier liiterature it says "combination heater".



Since the Navien CH-240-ASME carries the ASME section 4 approvals and plate, your argument that it is not a boiler is false, that's all.

VictoriaEnergy

It is a boiler

I've installed their on demand HWH units.  Never the boilers.



On the pro side; you get an impressive amount of design ingenuity for your money.  The units I've installed have had excellent initial reliability.



On the con side;  They're not very easy to work on, and although I haven't yet had to do it,  I don't look forward to taking it apart to clean out the heat exchanger.  Full of lots of little plastic/elbow/clip/adaptor/o-ring things that have a habit of easily breaking.  Since they are new to our market, and the US is not thier core market, long term parts availability and the service life are the biggest concerns for them.

   

NRT_Rob

actually

the navien dos carrier an AFUE-CA rating. That's pretty boiler like if you ask me.



I am hearing a lot of murmuring about problems, but nothing direct from a horse's mouth.

jonny88

be careful

they work great for on demand hot water.be careful though,for heating look into the model you buy.i do apologize but it was a long time ago when we did the install.there is a unit they make for heating i forget the model number,but the hot water unit will give you nothing but headaches if you want to run a heat source of it,also watch out for the filters underneath the unit,if they become anyway dirty the unit wont fire,easy fix though,just unscrew the filter and clean.it took us however a long time to figure out.u void the warranty if you run the hot water unit at more than 140 degrees,so be careful as to which unit you get

AFred

naviens

Had a few flow switches trip on some, EZ fix, slap the switch with your screwdriver handle, then go home.

I still havent decided if I like them or not, I think I fear them. They remind me of a quietside, and I dont want that nightmare again!!

HDE

Confusion

You are both confused, we are not discussing the Navien Tankless units but the Navien model CH combi boilers

CMadatMe

I'll Concede

That the CH-240-ASME is a boiler. The other CH models are not. I am not ignorant as to combi units. I was selling Vitodens combi's long before the isles at HD had tankless units...

HDE

Combi?

Viessmann makes a fine boiler, but since my last trip through Toronto, and a stop at their office, I'm sure their product lines hasn't changed, so calling their shared Ht/DHW circuit Vitodens a combi is like calling a single circuit tankless models a combi boiler also.

Currently there are only two states that require ASME on their boilers in order to be installed. So producing a near identical product and selling it for hundreds of dollars less that the H-stamped brother makes it no longer a boiler, even though its identical? I call that smart!

Your a passionate distributor employee no doubt, but there are other products besides Viessmann.

My Home Depot name bother ya? I've been on heating help about 7-8 years, this is my second screen name, years ago it used to bother people which was fun, not so much any more, but newbies like yourself always come along and it recreates the agitation I was once looking for. - LOL

Mark Eatherton

Chris....

Don't let the HD handle throw you. He knows a lot more about wall hung boilers than he lets on...



Trust me, the HD handle is meant to incite, and it obviously works in that vein.



ME

haventseenenough

haventseenenough

when did HD become a ligit plumbing and heating supply house? No offense, just wondering.

CMadatMe

Cowards Hide

Thanks for the heads up ME. You can't have a conversation with a coward. They hide in the dark giving them no credibility in my book.

HDE

Far from new

See it works (I've never worked at HD, but most have figured that out)



Thanks ME, we've had some interesting posts in the past.



One should note, manufacturers don't like coming here for one reason, maybe two, the product attacks and the know-it-alls. Having been in the boiler industry for 26+ years, worked for more than a few manufacturers, a new kid on the block would never rile me.

Mark Eatherton

Actually...

Home DEpot has their own wholesale supply chain, and have had a for a few years now.



They bought out a large wholesale concern a few years back.



http://hdsupplysolutions.com/shop/home?ref=http://www.google.com/search?client=safari&rls=en&q=home+depot+supply&ie=UTF-8&oe=UTF-8&alias=http://hdsupplysolutions.com/



ME

bill_105

Time to come clean

Why home depot employee? Why not Lowe's? Your knowledge of this stuff is pretty sharp,. and has been for awhile.

HDE

Lowes

Thanks Bill



Many years ago when so many contractors felt threatened by the big box stores, which we all know didn't turnout to be a threat, Lowes was non-existent in the northeast, where I once lived and worked when I chose my screen name. Lately I spend more time elsewhere online however I always check heatinghelp.com.



A little more about me



I've been at every AHR show since 1995, I used to enjoy the US ISH shows when they were in existence, I've been to ISH Germany 5 times, I've toured Grundfos in Denmark,

Rinnai and Takagi in Japan, so many ASPE's and PHCC's I couldn't begun to count, Viessman in heizung (automation is awesome) and too many boiler and pump manufacturers to count, Amtrol back in the 80's in Boston was memorable.



My job/life is to know as much as I can about the boiler and Tankless companies, that's how I draw a paycheck.



I can appreciate the passion of many contributors on heating help, I myself continue to learn lots, I haven't seen Dan speak in quite a few years, his incite and delivery of info was always the best.



Best to all, in all my years here maybe closer to 10, there is always something to learn even from the ones that are new at the industry, and add a different perspective, even when us veterans must help them see the big picture.



Lastly thanks to all that sent me the private thanks, complements and encouragement.

Dabbler

Done Venting?

Now that everyone is done venting, I will return to my original question, on a combi unit how many btu's are available for heat, and since the unit requires primary/secondary piping what is the head loss to size the pump. I have read the manual and cant find this information (unless I am looking at the wrong manual).

NRT_Rob

dabbler

Your questions are raising major red flags. If you can't even trivially easily answer those two questions I would hope you are getting some professional help here as you are not ready to work with this or any other hydronic combustion appliance.



No offense intended.

Dabbler

Need to know what I am getting into,

None taken, I am not a professional, have no intention of installing anything, asked a question so I could understand what I was looking at, the forum says ask your questions so I did, combi unit says 199,000btu's how much of that can be used for heating?

Mark Eatherton

Based on their literature....

Looks like around 160.000 btuH. (listed flow rates and delta T's).



Their literature is a bit scant in that area, and doesn't really spell out all of the parameters, but that's a fair bit of energy.



ME

HDE

same as published #

BTU's available heating is the input x thermal efficiency (96-98% I think)

So a 199,000, is capable of 190MBTUH+



Modulating firing rate is based on Delta T of S & R. Lets say the internal pump is 6 GPM. And you have a zone or zones totalling 15 GPM.



Mix Stream Formula (used to determine temps on primary/secondary circuits):



On a cold start (room temp of 70 deg), boiler set at 160 degrees



(Primary 160 degree x 6 GPM) + (Secondary 70 deg x 15 gpm) = 2010



Primary 6 GPM + Secondary 15 GPM = 21 GPM



2010 / 21 = 95 degrees



160 degrees boiler supply - 95 deg mixed return temp = 65 degree S & R boiler Delta T



65 DT x 500 x 60 = 195,000 BTU's



So at start up, the 199,000 BTU Combi or tankless would be fired at max BTU's.  





The head loss of the internal pump is basically a moot point since it requires primary/secondary piping unless you intended to make a large primary which isnt normal on a residential installation.

Mark Eatherton

According to their numbers....

as seen on their web site, they give a flow rate, and a delta T. THAT is the number I used in determining their output.



So, are those numbers wrong? Or am I misunderstanding the information they are putting out. Is the water in the appliance the space heating water, and the FPHXer for DHW, or is the water in the boiler potable water, and the secondary side of the FPHXer space heating water?



Page 4 of their literature attached.



http://www.navienamerica.com/PDS/ftp/CombiGasWaterHeaters/Brochure/Navien_condensing_combi_boiler_091103.pdf



The only heat exchanger that I am aware of that is 99% efficient is the reverse indirects, like Turbox max... and they WONT fit under the cover of the boiler :-)



ME

HDE

Close

The numbers published that you see are the DHW production flow rates at a given rise via a SS plate heat exchanger. You are correct in concluding it is a 160MBTUH plate exchanger, but not the combustion heat exchanger.



The CH Navien combi is opposite of the most tankless units and some other brand combis, such as a BAXI. In this case the primary and secondary heat exchangers are now the closed side and the DHW is heated via a plate using the on-board circ to transfer the heat. This same circ provides the flow for the primary loop or small loop requirements.



So the combustion efficiency/thermal efficiency is as high as 98%, but the DHW efficiency due to heat transfer losses is about 87% resulting in a CA-AFUE (combine appliance) of 92%



CA-AFUE is a fairly new rating and will be enforced on all combi's within a year or two. It is truly an accurate way to rate both operations over a year. Kinda brings up the argument of rating indirect tanks, will they ever? Or can they ever?

scott markle_2

viessman Combi

Hey HDE,



What's with the combative tone, Chris may have been wrong about the Navien but wouldn't it have been nicer to inform us all of this in a more civil manner. If I remember correctly dan has stepped in in the past to say the all Capitals was verboten.



Once you start playing the know it all game you can look kind of silly when your wrong. Since Viessman basically brought the first mod-cons to NA, (real H stamp pressure rated vessels) you might want to review their product history, The 200 series which is currently in it's second generation here in NA was indeed offered with a built in flatplate HX and diverter solenoid making it a true (and probably the first in NA) combi boiler.





Chris may be be acting a bit defensively, but your insinuation that he is too provincial to be familiar with the european comi-boiler nomenclature is insulting. It also gives me a little more insight into your monicker, you revel in inciting those that might be threatened by the big box retailers. It's not that inciting opinion is bad. But I suspect the attitude of superiority you showed with Chris ( ie the you don't know what your talking about because you've never been abroad tone). Is the same preconception you bring to the people you want to incite with your fake name.



I'm not a huge fan of the combi- format except in very space limited applications, problem is that the kind of spaces that don't have room for an indirect are generally too small for an appliance that can make continuous hot water. BTW I the vito combies I have installed are still running quit nicely 2 of them since 2004

Mark Eatherton

Before you go casting stones...

First off, I agree with you regarding people using their real names instead of fake screen names. If it were up to me, it wouldn't be allowed. But some people (like HD) have a reason for not divulging their real identity, and that is their perrogative. Dan doesn't require users to use their real names. Through his software, he knows exactly who they are, but doesn't require them to use their real names in their postings.



With that said, what do you think other people think of YOUR screen name???? What the heck is a HVHEHCCA :-)



Most regular contributors know who you are and who you work for, but many new comers wouldn't because you aren't using your real name, no? And to the best of my knowledge, you have NOTHING to hide from, correct?



It's the people who come in here, and make a mess under a cutesy fake screen name, and then disappear (trolls) that make the hairs stand up on the back of my neck. Like I know you, your lack of a real screen name does not bother me. I know who HD is, and it doesn't bother me either, and you shouldn't let it bother you either. I'm fairly certain that if you attempt to contact him off line, he will respond in kind, and once you see who he really is, and why he's not using his real name, I hope you will understand.



He's here to stay, and is legitimate and knowledgeable in his postings. You too have learned something from him.



Now, let's get back to educating each other and consumers, shall we.



ME

HDE

?

What capital letters? ASME and a few others is always capitalized.



My correction for Chris' strongly worded incorrect statement offended you?



Not sure I understand your stance on that one.

Mark Eatherton

Got it...

I thought that ws the case, but their literature I referenced is not real clear.



As for testing indirect DHW heaters equally, I think it can and should be done, using a standard test, using standard operating parameters. That is the problem with tankless, and indirects. The manufacturer gets to decide what information the consumer is presented, and all they see is the Gallons Per Hour, and not the missing information that is critical in making the decision, like degree F rise for those GPH...



A BTU is a BTU is a BTU, and they all can only do the SAME thing to water. That's the problem with letting the marketing department tell the engineering department what THEY want to see...



If all indirects and tankless heaters were truly rated the same, the consumer would be capable of making a decision without intervention from the marketing department...



Thanks for the feed back.



ME

scott markle_2

Bold,Capitals, what's the difference?

Your not guilty of the classic caps lock, but the tricky font size alteration is basically the same.



My issue is this, you are baiting a certain type person with your name, not that you hide your identity, but that your identity is false. Actually I don't even have a problem with that.



What bothers me is the thinly veiled sense of superiority that was revealed in the recent exchange. It's one thing to provoke but condescending provocation is just plain ugly. you should hide your cards better.



If we're going to play the who knows more about combi's game it' your turn to say I was wrong about Viessmann's history importing combies



I think what you would really love is for some proud redneck to embarrass him self by saying something stupid or vaguely racist about what crap they make in korea and how HD is selling out to the Asians etc. Makes good theater but hardly advances the cause of better heating and hot water systems.

HDE

Inciting or exciting?

2.1 GPM at a 35 deg rise? whats that .75 gpm at 70? what will one do with that? - Sorry

BTW, I did nothing to change fonts, but it sure as heck bothered you.

I would be equally involved if someone got on here and said don't buy Rinnai, their contaminated with radiation.



Redneck? looks like your stereotyping may offend some people. I lived in TN, now I want an apology

scott markle_2

Offended

Sorry if I offended, but i think your still playing games.I don't get your gpm metaphor.

Am I supposed to check your math and prove my hydronic credibility? Chris may have swallowed your bait and lost his cool, but I suspect that's what your fishing for. If your anonymous you never have to say you sorry.

CMadatMe

We Shall

I have to agree I did learn something from him. The tone that he set brought out the Jar Head in me and if I offended I apologize. With that said, I wouldn't expect someone within the mfg side of the industry and obvisouly well educated on the subject to get off on inciting others through sarcasim. But that is my fault for letting it get to me. I would though, expect them to inform and educate as he did in his further post on the heating btu's of the Navien. That was a well explained and informative post.



From his little bio he started in the industry just a few years earlier then I. While I am originally from New England I've probably crossed his path a time or two. He would have grown up in the early Viessmann, Stadler days as I did.



Mark, I don't hide my name...Its at the bottom of every post

HDE

My my such defensiveness

Thanks Mark.

In the industry we call these imported products and their manuals and literature to be written Japenglish, Korenglish, Chinenglish, you get the point, there is a need for interpretation. I have noticed it continues to get better.



I would once again be remiss for not acknowledging the countless Wallies that have sent me a private message thanking me for "standing up and correcting" .

You are all right, "the site is for all contributors" not just a few. And yes, wear your "big boy pants"

Regards.

CMadatMe

HD

Being that you are well versed in the combi field what are your impressions and take on this product?

http://www.triangletube.com/TriangleTubeProduct.aspx?CatID=1&PID=31



I was told that this isn't being made by the parent company ACV. Its a another mfg across the pond that has had success with it. Do you know who the parent company is and are you aware of any past or current issues with it?



I'm trying to educate myself on this unit before making a decision on whether we should stock it. We also sell Navien by the way.. Thanks

Plumdog_2

OK, I'm curious!

Mr. Home Depot Employee:

Did you go by "TANKLESS" handle just before Katrina?

Just askin. Always like your posts, by the way.

HDE

No

No not me, I think that guy is in Florida, if I recall