Navien 100,000 btu heating

Snowmelt

I was on phone with navien, my 2 workers went to the class.



Here is what I wad told when I asked him how can you get 100 K out of a pump that was only going around 5 G.P.M.



He was a nice guy I am not sure if I am saying it correct.



When there is a cal for heat and when a zone opens up the water will be pulled up the first tee as the pump in the navien also pulls the water from the cold return, so your adding them two numbers up.

He also said you need to increase the pipe size to 1-1/4, that's how it's able to accomplish 100,000 btu

He also said he preferred delta t pump because there machine operates better with a set delta t which I think they had a dipswtch for.

icesailor

Ohm's Law:

You mean sort of like Ohm's law? The higher the voltage, the less the resistance?

The bigger the pipe, the less the resistance? I 1/4 copper isn't all that much more for a tremendous increase in lo capability.

As I see it.

If it tales 4-1/2" pipes to equal a 1" pipe, 4- 1" pipes to equal a 4" pipe, why not use 1 1'/4" pipes?

4- 1/2" PEX pipes do not equal 1" copper tubing.

HDE_2

Watched Barbas webinar today

He pretty much explained today in his webinar using a lochinvar boiler with 5 GPM with a system requirement of 80,000 BTU's as an example how it works. Its not that hard to understand, and also realize not all boilers fire or operate on a 20 DT.

Heat emitter DT/BTU is different than boiler operation to understand heat transfer available.

Tim Potter

HDE,

Where is that webinar, I would like to see it



Thank you:



Tim

HDE_2

From an email

If you wish to view a recording of the webinar, you'll find it archived in Taco's "The Neighborhood," an online community for education and development. The Neighborhood requires a free, one-time registration that is separate from the Taco FloPro Team. You may join The Neighborhood by using this link:



http://flopro.ning.com/?xgi=1VtkVecLk6Z9DA



You'll find this week's webinar, along with all of our past webinars, archived on the right hand side of the front page.

Snowmelt

Ice sailer

I know what ohms law is but I have no idea on what your talking about. Pipe size had to do with how many btu go through the pipe, I may not be the best plumber in the room but I definitely don't over think things.

Gordy

Head

Is what ice is talking about he's just using an electrical resistance example. The bigger the pipe the less pump energy needed. It's not all about the btus pipes can carry. It's also about moving those btus efficiently through the pipe from point A to B.



Water, electricity, gases, and even vehicular traffic have certain parallels. That's the highway they travel.

Snowmelt

Now I'm more confused

On my own personal home I have a takagi water heater with 1 inch on primery and 1-1/2 on secoundary. I estimated 100 btu per sq foot I have 1,850 sq foot drive way, I only get 4.5 to 5 gpm on my primery loop. I know this because my remote shows gpm.



I am able to get the snow off the driveway with a nice foot and a half of snow. I would guess it's about 185,000 btu driveway. So how is his done,I have to be heating up more then 50,000 btu.



To throw 2 more things in the equation

1. 11 loops of 3/4 tubing

2. Gas bil is under $25.00 per snow fall

3. 0011 pump

4. 75 %e glycol

Gordy

More info.

What's the circ on the primary? Assuming the 011 is on the secondary.

I would trust calculated pump curves before gpm read out.



What's the takagi output?



1" copper will carry 72k with proper design flow rates, more if that's exceeded.



How is the snow melt operated weather responsive, manual?



11 loops each covers 168 sf. Loop lengths?



What's the deltas on primary, secondary? I would assume very wide.

At 5gpm the delta would be 74*



At 18.5 gpm the delta would be 20*

Paul48

help

I need some more direction to that webinar. Naviens answer seems to defy everything I've learned about P/S piping.

Gordy

Never doubt

What you know to be true.



I think this has been covered numerous time on Navien threads.

Snowmelt

More info

More info.

What's the circ on the primary? Assuming the 011 is on the secondary.

I would trust calculated pump curves before gpm read out.

009 like I said I get between 4 and 5 g.p.m. Depending on my return temp, when it first start my return temp is 40 when it gets to 60 in like an hour of contusions run it goes up to 5.

What's the takagi output?

199,000 btu



1" copper will carry 72k with proper design flow rates, more if that's exceeded.



How is the snow melt operated weather responsive, manual?

On a ground sensor it does keep up and shut off so I actually lowered my temp fro 140 to 130



11 loops each covers 168 sf. Loop lengths?

I be leave it was 275 ft of 3/4 tubing, last two loops were 250 all where done at 6 inch center as much as I could do.



What's the deltas on primary, secondary? I would assume very wide.

At 5gpm the delta would be 74*



At 18.5 gpm the delta would be 20*



I swear after like 2 hours my return temp would be warm I want to say around the 100 degree mark. I want to say between 30 and 40 * I measured all piping and I think I came up with 50 to 60 gallons of water.

heatpro02920

I have had customers

ask for navians, and I always try to steer them in a different direction... They just are not worth the aggravation... I know some people say "I have had great luck with them" but I hear a lot of others saying the opposite... I have also been on the service side of them more than I should have... Plus when I spoke with their cs a few times, I was not impressed or satisfied...



You know the old sayings "you get what you pay for" or "if it seems to good to be true, its probably as good as it seems"... There are so many good units out there why mess around... I would honestly rather install a Rinnai unit with a fphx and make less money, than mess around with the navian unit...

CMadatMe

Its Not that Hard to Understand

Boiler/Primary Flow Rate = 5gpm

System Flow Rate = 10gpm



See attached....It's not btu/hr you need to worry about it's the (T2) System Supply Temp. Yes you can get 100,000 btu/hr but not of 180 degree water its impossible unless you're boiler is making around 190...



The PDF is converted from an excel file that I made into a calculator. I use it all the time on retrofit jobs to make sure my design supply water temp is enough to get the load of out the emitters.



I've had this conversation with Navien plenty of times. Once you bring it up they look at you like a deer in the headlights..

Snowmelt

Thanks cris

Thanks that doesn't look to bad, do you have a heat loss program thAt you use in excell?

CMadatMe

Heat Loss Program

No. I have Ziggy's software and I use Uponor's ADS software.



You do see that they system side is only running on a 10 degree delta right? I used 160 return to simulate what installers think. That they are running a system side 20 degree delta supplying 180 degree water... It's just not the case. If you change that system return you system supply temp is going to decrease..