# Another Navian Ch240 Install



## Catlin987987 (Nov 12, 2010)




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## SHAUN C (Feb 16, 2011)

What kind of piping is that?


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## plbgbiz (Aug 27, 2010)

SHAUN C said:


> What kind of piping is that?


Looks like fused Aquatherm.


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## ZL700 (Dec 8, 2009)

I designed a big project with these a year ago. 
I like how you know to use a hose from domestic side to flush, fill and purge the closed heating side.
However, unless I cant see it how about the missing street pressure connection to the auto fill valve? 

Contractor on my job didn't follow my drawings 100%. 

It wont be long before error code 2 for attempting to fill and lockout error code 28 isn't filling shows up.....


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## Catlin987987 (Nov 12, 2010)

ZL700 said:


> It wont be long before error code 2 for attempting to fill and lockout error code 28 isn't filling shows up.....


Only if there is air still in the system or a leak. But there is an Axiom tank installed now.


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## dplumb (Jan 6, 2013)

Here is one I did yesterday. Feel free to pick apart.


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## dplumb (Jan 6, 2013)

I just had a rep in Mass do a demo with that piping that you used Catlin. Big in Europe I hear. Is that where you are? They wanted HUGE money for the tools for that stuff.


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## ZL700 (Dec 8, 2009)

Catlin987987 said:


> Only if there is air still in the system or a leak. But there is an Axiom tank installed now.


Exactly I've yet to see a system that is air free right after install or doesn't lose some water over time. Those grundfos for instance lose water from the motor cap area with only a o-ring seal. The Navien is full of o-rings, they will allow the hydronic water to diffuse its way out, can't stop it.


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## ZL700 (Dec 8, 2009)

*Dplumb*

Navien offers better and easier ways to pipe the CH

http://www.navienamerica.com/__DATA/Tech/2012/12/19/CH Application Drawings.pdf

I like these better, increased heat outputs, as the loop return doesn't drive down modulation. Whether you buy their manifold or make your own I think it is easier and does perform better. 

Heating system is the primary now, and the boiler is the secondary injecting heat into the heating primary. The boiler now always sees the coldest water for efficiency and all zones would receive even water temps.


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## Catlin987987 (Nov 12, 2010)

dplumb said:


> Here is one I did yesterday. Feel free to pick apart.


The only thing I could pick apart was you used TACO ciculators,:laughing:. JK


dplumb said:


> I just had a rep in Mass do a demo with that piping that you used Catlin. Big in Europe I hear. Is that where you are? They wanted HUGE money for the tools for that stuff.


The tools will save you in labour, the fittings are alittle more then copper.
I think each die size is around $120
and the iron is $600


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## Catlin987987 (Nov 12, 2010)

ZL700 said:


> Navien offers better and easier ways to pipe the CH
> 
> http://www.navienamerica.com/__DATA/Tech/2012/12/19/CH Application Drawings.pdf


I dont like how they pipe in there domestic storage tanks, the domestic heating cycle runs for too long and I have seen them run out of hot water.
We pipe them like this


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## ZL700 (Dec 8, 2009)

Catlin987987 said:


> I dont like how they pipe in there domestic storage tanks, the domestic heating cycle runs for too long and I have seen them run out of hot water.
> We pipe them like this


So all your doing is preheating and storing water so the combi doesn't need to when there is a domestic draw?

I think you may be missing part of the point why they do it that way. It eliminates the constant loss of heating and changeover times every time someone draws a little domestic hot water. Especially good for a dishwasher or other small draw that needs 1-5 gallons, no need to kick over to domestic and short cycle the burner. 

If you want to pipe storage for high draws the cold water should feed both plate inlet and back feed bottom of tank, with hot water leaving tank at top tank. That way you have both burner and 3/4 of storage to meet high flows.


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## Catlin987987 (Nov 12, 2010)

ZL700 said:


> So all your doing is preheating and storing water so the combi doesn't need to when there is a domestic draw?
> 
> I think you may be missing part of the point why they do it that way. It eliminates the constant loss of heating and changeover times every time someone draws a little domestic hot water. Especially good for a dishwasher or other small draw that needs 1-5 gallons, no need to kick over to domestic and short cycle the burner.
> 
> If you want to pipe storage for high draws the cold water should feed both plate inlet and back feed bottom of tank, with hot water leaving tank at top tank. That way you have both burner and 3/4 of storage to meet high flows.


That drawing assumes theres a dip tube. With navians drawing you are mixing cold water with the storage water. If the with such a small delta T it take for ever to mix 140F water into the storage tank holding 120F water. It the tankless could put out 160-180F water then I think there drawing would work alot better.


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## Plumbworker (Oct 23, 2008)

I see you started using hydro separators :yes:

That buffer tank design is strange.. most tankless heaters have burner modulation issues with "preheated" water.. the dhw should be drawing from the tank with mixing valve..


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## CaberTosser (Mar 7, 2013)

Throw a valve in on the pipe to the expansion tank, it sure makes it a lot easier to swap one when its bladder fails. I'll usually also pipe my expansion tanks that they act as an air trap, then if their bladder bursts the air is not introduced to system.

I have one client building where part of the boiler room was retrofit with that fusion weld pipe for a new boiler install (not by us), but they should have halved the hangar spacing, as it droops between supports and looks rather poor as a result. This is on 3" piping.


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## Catlin987987 (Nov 12, 2010)

CaberTosser said:


> I have one client building where part of the boiler room was retrofit with that fusion weld pipe for a new boiler install (not by us), but they should have halved the hangar spacing, as it droops between supports and looks rather poor as a result. This is on 3" piping.


If they Followed (or read) the manufacture instructions it wold have fixed that problem.


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