# Restaurant boiler/dhw install...help!!



## Hynds99 (Feb 26, 2016)

Hi guys I'm new on here, been in the trade for almost 13 years, just started my own company and one of my first commercial jobs is a new heating and dhw system for a good sized Japanese restaurant. The owner is leaning towards a navien 240 combi, because of rebate incentives and floor space concerns..... But there's enough floor space already for a small bowling alley in the basement...smh... But anyone with any suggestions on a decent system would be greatly appreciated, wall mount boiler with an indirect sounds more applicable to me but open to any idea, concerns, any help. They currently have a 75 gal residential hwh and a 175k btu weilmclain hydronic boiler with 5 zones. Thank you in advance guys. Also some suggestions on pricing? I promised to remove an abandoned oil tank and a 10' 2x3 wall, build a new wall for new heating unit.


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## plumbdrum (Nov 30, 2013)

First advise is go to the intro section.


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## plumbdrum (Nov 30, 2013)

I would not recommend a navien for a commercial kitchen, to much cycling of the unit without a storage tank. I would go with a condensing boiler with an appropriate sized indirect based on the needs of the restaurant .


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## Plumbus (Aug 4, 2008)

A Navien would not be able to keep up with peek use unless you daisy chained a few together. For efficiency and flexibility I agree with plumpdrum.


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## Hynds99 (Feb 26, 2016)

Well if the navien doesn't seem viable, what would you suggest?


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## plumbdrum (Nov 30, 2013)

I inspect, not endorse. I'm sure someone will chime in


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## plbgbiz (Aug 27, 2010)

Hynds99 said:


> Well if the navien doesn't seem viable, what would you suggest?


Put in a commercial tank type WH and through the tankless idea into the scrap heap it deserves.

-OR-

Install a tankless and put your worst enemy's company name on it.


The problem is not the brand. Any tankless will be a mistake.


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## ShtRnsdownhill (Jan 13, 2016)

Navien SUCKS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! stay away...........put back a commercial WH and a cast iron boiler, or you will suffer long and hard for not doing it...


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## GREENPLUM (Jul 27, 2008)

ShtRnsdownhill said:


> Navien SUCKS!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! stay away...........put back a commercial WH and a cast iron boiler, or you will suffer long and hard for not doing it...


What's yer problem with navies, there quality tankless heaters


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## GREENPLUM (Jul 27, 2008)

They make comm dishwashers with preheaters


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## plbgbiz (Aug 27, 2010)

GREENPLUM said:


> What's yer problem with navies, there quality tankless heaters


Navien lies in their marketing and uses bait/switch tactics to leave plumber's responsible for undersized gas lines. They use water quality technicalities to avoid honoring warranties.

Average product, sub par ethics.


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## ShtRnsdownhill (Jan 13, 2016)

GREENPLUM said:


> What's yer problem with navies, there quality tankless heaters


the combo units suck, after the hurricane( sandy) on long island a bunch of those units were installed, and now 3 years later the heat ex-changers are cracking, the computer boards do some wacky things and they let lose on the relief valve , but when I get called they are not reliefing..I tell the people call back who put them in and they tell me hes out of business..musta made a killing and shut his business down knowing in a few years he would be back..mabe the none combo units are better, but the combos have some serious issues..I must have gotten 6 different calls about these units in the last few months, all from the same area..


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## GREENPLUM (Jul 27, 2008)

I've had great results with navies, happy happy customers

Restaurants and a gang bathrooms @ truck stops


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## GREENPLUM (Jul 27, 2008)

ShtRnsdownhill said:


> the combo units suck, after the hurricane( sandy) on long island a bunch of those units were installed, and now 3 years later the heat ex-changers are cracking, the computer boards do some wacky things and they let lose on the relief valve , but when I get called they are not reliefing..I tell the people call back who put them in and they tell me hes out of business..musta made a killing and shut his business down knowing in a few years he would be back..mabe the none combo units are better, but the combos have some serious issues..I must have gotten 6 different calls about these units in the last few months, all from the same area..


Installer error, the units are tested before they roll out


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## ShtRnsdownhill (Jan 13, 2016)

GREENPLUM said:


> Installer error, the units are tested before they roll out


im thinking something in the water, or the units dont hold up to treated water from the municipality..chlorine or who knows what else they put in the water, but I looked at 2 that had split heat exchangers on the DHW side..


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## plumbdrum (Nov 30, 2013)

Hynds99 said:


> Well if the navien doesn't seem viable, what would you suggest?


Ohhhhh ok, triangle tube


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## Flyout95 (Apr 13, 2012)

greenplum said:


> i've had great results with navies, happy happy customers
> 
> restaurants and a gang bang @ truck stops


what?


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## ZL700 (Dec 8, 2009)

plbgbiz said:


> Navien lies in their marketing and uses bait/switch tactics to leave plumber's responsible for undersized gas lines. They use water quality technicalities to avoid honoring warranties.
> 
> Average product, sub par ethics.


Still don't understand how lower than the past norm low inlet pressure requirement gas combustion systems with premix burners work?


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## ShtRnsdownhill (Jan 13, 2016)

plbgbiz said:


> Navien lies in their marketing and uses bait/switch tactics to leave plumber's responsible for undersized gas lines. They use water quality technicalities to avoid honoring warranties.
> 
> Average product, sub par ethics.


you size the gas line according to the units BTU..how is that guessing?


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## plbgbiz (Aug 27, 2010)

ShtRnsdownhill said:


> you size the gas line according to the units BTU..how is that guessing?


Yes I do size by BTU load. But Navien says that is not needed. 

In their class and marketing they brag about not having to increase gas pipe size. Just hook it up to the existing 1/2" line used by a standard 35K tank type burner. Their space age gas valve will vacuum enough gas out of the line to make it work. 

Just be sure Mr. Homeowner doesn't need any gas heat or cook on gas while they need hot water. The Navien rep explained in detail how awesome it is that their valve can rob gas from other fixtures to fulfill its demand.

I've had more than one homeowner send me on my way for this specific reason. "Navien said I don't have to increase my gas pipe size. I'll get someone else that isn't trying to scam me."

It's a load of marketing BS. 

Navien rep never could get the frog out of his throat when I pointed out the 3/4" gas inlet on the unit he said could be served by 1/2" pipe.


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## plbgbiz (Aug 27, 2010)

ZL700 said:


> Still don't understand how lower than the past norm low inlet pressure requirement gas combustion systems with premix burners work?


Understanding it, and agreeing with the lie used to sell it are two very different things sir.


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## ShtRnsdownhill (Jan 13, 2016)

plbgbiz said:


> Yes I do size by BTU load. But Navien says that is not needed.
> 
> In their class and marketing they brag about not having to increase gas pipe size. Just hook it up to the existing 1/2" line used by a standard 35K tank type burner. Their space age gas valve will vacuum enough gas out of the line to make it work.
> 
> ...


well ill be honest and want to see that in writing in a navien manual or it doesnt exist, if you think a 200,000 btu unit will be fed by a 1/2 line...thats wishful thinking...


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## plbgbiz (Aug 27, 2010)

ShtRnsdownhill said:


> well ill be honest and want to see that in writing in a navien manual or it doesnt exist, if you think a 200,000 btu unit will be fed by a 1/2 line...thats wishful thinking...


Copied from their website...



*Better Adaptability to Gas Systems* The Negative Pressure Gas Valve and Fan with Dual Venturi operation allows for better adaptability to low gas pressure applications. This industry leading technology makes it possible for the NPE to be installed with 1/2" Gas Lines up to 24'.
Easy residential tank replacements.


Now you tell me, to the novice homeowner what does that statement mean? This 1/2" gas line crap is all over their literature. 



I first started installing tankless units in the early 90's. Since that time I have yet to see a residential application where the existing 1/2" gas pipe sizing in the WH closet would accommodate a tankless WH.

This is why I call BS on Navien marketing. The units work. Fine. But so do others if sized properly. It's their marketing lie that I have issues with. Does it not make you wonder what else they lie about?


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## bct p&h (Jan 19, 2013)

ShtRnsdownhill said:


> well ill be honest and want to see that in writing in a navien manual or it doesnt exist, if you think a 200,000 btu unit will be fed by a 1/2 line...thats wishful thinking...


It's on their website.
What they say if you actually ask them is that you can use the ½" drop as long as the main is sized correctly. Pretty sure it's in the fine print.
I've asked the question what if they have the stove on and it sucks the burner out? Now that burner is going to be spewing gas until someone notices. Not a good idea in my opinion.
I've put a couple hundred of them in. Most common problem I had with them was the 3 way valve and the flow sensor. They have their place but most people believe all the hype and think it's the only way to go.

As far as a recommendation for the restaurant, I'd go with an HTP fire tube with an indirect or you could try the HTP EFT combi if it sizes out.


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## ShtRnsdownhill (Jan 13, 2016)

navien is full of $hit..10 feet of 1/2 pipe will support 132,000 btus no more. so 24 feet is a pipe dream, but do they say at what pressure?here is a chart for btu carrying capacity of gas lines..


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## ShtRnsdownhill (Jan 13, 2016)

plbgbiz said:


> Copied from their website...
> 
> 
> 
> ...


im gona stand by earlier comment that there combo units suck...Im starting to see alot of 3 year old units fail with split heat exchangers and do funky stuff with the computer in them, I have installed alot of takagi wall hung units and so far no issues..


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## bct p&h (Jan 19, 2013)

ShtRnsdownhill said:


> navien is full of $hit..10 feet of 1/2 pipe will support 132,000 btus no more. so 24 feet is a pipe dream, but do they say at what pressure?here is a chart for btu carrying capacity of gas lines..


There is something that you are missing here. They use a negative pressure gas valve. It actually sucks the gas put of the line. That's how they are able to do it. My problem with it is that they are stealing gas from other appliances.
I'm not defending them in the least. I just think you should have all the information before you start bashing on them. I'm not putting one in my house and I try to talk most people out of them because they do not work in every situation. There are a few places where they do work and they actually work quite well.


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## plbgbiz (Aug 27, 2010)

ShtRnsdownhill said:


> navien is full of $hit..10 feet of 1/2 pipe will support 132,000 btus no more. so 24 feet is a pipe dream, but do they say at what pressure?here is a chart for btu carrying capacity of gas lines..


Doesn't your code book have a chart for gas pipe sizing when connected to a hoover vacuum? That's the only way Navien gets their numbers to work.


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## ShtRnsdownhill (Jan 13, 2016)

bct p&h said:


> There is something that you are missing here. They use a negative pressure gas valve. It actually sucks the gas put of the line. That's how they are able to do it. My problem with it is that they are stealing gas from other appliances.
> I'm not defending them in the least. I just think you should have all the information before you start bashing on them. I'm not putting one in my house and I try to talk most people out of them because they do not work in every situation. There are a few places where they do work and they actually work quite well.


im not bashing navien on info about gas lines, im bashing them from the half dozen units I have recently looked at with all kinds of problems...


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## ShtRnsdownhill (Jan 13, 2016)

plbgbiz said:


> Doesn't your code book have a chart for gas pipe sizing when connected to a hoover vacuum? That's the only way Navien gets their numbers to work.


LOL...right next to the transparent aluminum supply


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## bct p&h (Jan 19, 2013)

ShtRnsdownhill said:


> im not bashing navien on info about gas lines, im bashing them from the half dozen units I have recently looked at with all kinds of problems...


Do you have any pictures of the units you're having problems with? I haven't installed one in about 2-3 years but I never had any of the problems you've been having. I'm just wondering if it was installer error or manufacturer defect.


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## ShtRnsdownhill (Jan 13, 2016)

bct p&h said:


> Do you have any pictures of the units you're having problems with? I haven't installed one in about 2-3 years but I never had any of the problems you've been having. I'm just wondering if it was installer error or manufacturer defect.


 2 split DHW heat exchangers...that I doubt that could be installer error...then some units surge and then nothing for weeks..very sparatic..


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## plumbdrum (Nov 30, 2013)

I'm on my second Navien at my house. First heat exchanger failed, a month before it failed my 3 way valve let go. Not sure how long it was leaking but I'm assuming all the fresh water being injected into the unit to maintain pressure was the culprit. Bottom line, not always installer error, but many time yes.


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